# Mics engine ramblings related to common questions.



## Machinest-guy (Jul 19, 2019)

Good morning all, and thanks for this comprehensive document, Ladd.

I get the strong feeling this should be published somewhere, as it clearly has relevance for a lot of what happens now with the ‘old car’ hobby. The background context and way in which this science has developed is fascinating and makes for a very interesting, and informative read for those with a technical interest. Particularly love the Smokey Yunick story: first-hand records like that are both entertaining and valuable.

I have no remarks for correction of this (how could I have?) and think it would be a very valuable contribution to the record for those that are looking for advice, so very happy for this to go on the forum if possible.
Best wishes to all
Roger

Good morning, I’m the fellow who provided parts and machine work to Roger, who’s engine was the subject of his thread. Our compiled and edited email correspondence was published in Europe several years ago for his car club which we enjoyed doing back then. Because I now read so many of the same questions here on the Pontiac forum I’m offering a cut down / further edited version again in hopes of helping some of our club members have more fun faster. I am an un-apologetic performance oriented engine and car builder, but have a strong sense of historic importance needed for restoration work. While I’ve become a semi-retired automotive shop owner, my Blog typing time is quite limited so I did a cut and paste putting this together over the last month from a quick survey of popular questions being posted. Maybe I should have included more Pontiac specific information and stories. Maybe next time, or maybe not. In any event feel free to cut, slice, or ignore whatever doesn’t move your car interests ahead because this narrative jumps over many subjects.
And this information was written 8+ years ago for Roger who lives in the UK as part of a job in my shop helping him recreate from blueprints, photographs, raw metal stock, and OEM castings, an FIA legal A/C Cobra to run at Le Mans in their vintage car class. So it has become a bit dated since then because additional changes to oil formulation have occurred, fuel composition evolved, and racing / restoration technology advanced. I feel it was more than just nice of Roger to be so candid with his adventures building a car and engine then allow publication of his words.
However history is what it is, so I believe there is yet value to be had here because the same questions seem to be asked over and over again in these Pontiac forums. I’d hope our Pontiac forum moderators will put this somewhere it might be shared by those who have a passion for car engines and how they work. I would hope nobody is offended by reference to brands other than Pontiac….. Roger’s club in the UK had a perspective of “American cars” vs the European brands, so when I initially wrote I didn’t limit mentions to everything specifically Pontiac – just American.
--------------------------------------------------------------- 
June 2016
My name is Ladd. I wish to offer some thoughts to your group about engine break in and oil as they pertain to this build because many of you are doing similar work which may be improved upon. It seems there is a lot of interest in rear main seal issues too. I’d like to approach this from a perspective of posing then answering questions based on decades of working conversations with leading experts in various fields of automotive and aircraft engine / vehicle performance. And I’ll mention historical data that leads us to the technology used today. While I’m just a lone guy in a “hole-in-the-wall- shop; I’m also a guy lucky enough to have been mentored by noteworthy men and institutions who took time to invest in me answers to many questions so my work could become better. Perhaps this bit of writing will be of interest to you while given in that spirit of sharing knowledge. 

Engine break in was historically needed as a “finishing” operation because OEM production machine work accuracy and surface finish quality were not acceptable for full power operation “off the production line”. This situation existed from the beginning of combustion engine technology until recently, perhaps arguably, until the last couples of decades (2000). Thereafter improvements in OEM manufacturing virtually eliminated need for post assembly mechanical break in art to mate and seal engine components. Along with benefits of greater power being available sooner, great increases in engine longevity have been realized. Elimination of a wearing process to mate parts for operation generally called “break in” directly yields greater functional life.

A question of importance to us now, as we renew half century and older engines is: how do we apply new technology to obtain the same benefit of more power, sooner and longer? And if that benefit is built into a re-manufactured engine, how does one hang onto it? I believe answers to those questions are fairly simple to understand, once presented for discussion, and are found in three general areas. They are; manufacturing processes and materials, lubrication, and operation practices.

The small block Ford, Chevrolet, and Pontiac (GM) engines popular for restoration today were generally designed with knowledge accumulated by engineers prior to late 1950’s, then produced starting in the very early 1960’s. They were considered “modern” back then. They were designed around improved technology, notably sealing materials of cork / rubber and simple flat metal / carbon based center filler for gaskets. They had bi layer bearings, and improved alloy fully machined piston rings compared to engines of prior decades. Prior engines used felt / leather seals, flat copper sheet or asbestos core gaskets, and Babbitt bearings. Those engines had low alloy poured cast ring technology. Those newer designs of the '60's also used improved mass production manufacturing process, including select fitting and a defined break in process instead of prolonged hand fitting and trial fit assembly process.

However legacy practices needed to produce longer lasting engines and better power from older designs lead to unnecessary and sometimes damaging events when applied to the then new designs. For example; running new engines for short time intervals with cool down cycles diluted oil with fuel, use of very low temperature thermostats (or none at all) fouled cylinders with carbon, and introduction of abrasive compounds to “set the rings” became obsolete, yet were (and sometimes are still) part of some mechanics considerations when dealing with a rebuilt modern engine. Retrofitting solid copper gaskets and leather oil seals sometimes had significant negative issues back then, and would be nearly unthinkable today.

Break in oil and oil additives were also marketed and used frequently. It is my opinion most break in oils of the 1940’s to the 1970’s fell into several groups. They were (for the USA market) mineral oil based, and had limited additives but lighter viscosity compared against then standard 30w oil. They functioned by providing additional marginal lubrication to the cylinder wall and ring set so those components would wear into a functional sealing condition (hopefully without seizing) while holding manufacturing debris / grit, in suspension. Holding debris and grit in suspension was not good for bearings so that oil mixture was drained as soon as “normal” compression pressures were obtained. The also led to “oil flush” products and procedures being implemented. Many of these products were similar to current Sunnen honing oil now used in abrasive cylinder finishing machines worldwide. The next group were viscosity enhancers which claimed to thicken and/or improve anti seizing risks in bearings when added to normally used oil products. STP is a brand name which comes to mind. It was not beneficial for seating new rings (its ring claims were to restore compression in worn out ring sets) but was sometimes mixed with mineral oil additives in an attempt to gain advantages advertised by both product types.

Another additive group were chemically active additives to enhance properties of typically used oils. They contained anti-scuffing and detergent chemicals to bond to grit and debris mixed into “high quality” base oil stocks. It made these products expensive but beneficial. Most major vehicle and equipment manufactures had proprietary blends sold through their parts distribution networks. At the risk of oversimplification of a complex market environment and technical research it can be said this class of break in product evolved into additive packages now in modern oil.

Because some of these products were so effective as to become adopted worldwide in regularly used oils, need for them as break in supplements declined. Some of them were removed for protection of emission control devices in the 1990’s causing accelerated wear of camshafts and valve train parts. Resurgence of break in product marketing then followed a genuine need for anti-scuffing agents, as did resurgence of folklore and legacy practices when ZDDP was phased out. I should credit Roy Howell, a Cornell graduate appointed as Chief Chemist at Red Line Synthetic Oil Corporation, Dema Elgin a camshaft grinder and instructor at De Anza College, and Joe Mondello who founded the Mondello Technical Institute for this understanding gained in many conversations over many years’ time.

We are now faced with continuing technology advancements leading to production of today’s modern engines. Gaskets are now neoprene / specialty rubber blends or can often be of coated embossed steels. Specific adhesives and thread locking / lubricating products are common place. Tri-layer and flash coated bearing are typical parts while moly faced and low tension / multi material ring packages are also very common. These types of parts are also available for our old Pontiacs as retrofit aftermarket items.

In conversation with John Erb, Chief Engineer, KB Pistons in the 1980’s he related a story about building pistons for Chrysler. They wanted to know what to expect by way of variation between larger and smaller pistons in manufacturing so they could plan their select fitting procedures. John told them there was not going to be a manufacturing variation significant enough to warrant any select fitting. Chrysler did not believe that claim initially, but in the end found modern piston manufacturing to be so precise a legacy practice of select fitting was no longer needed in their assembly line. 

So I would suggest we, as mechanics and hobbyists, also have an even larger body of legacy practice which worked on the ‘50’s to ‘90’s engines but sometimes doesn’t work or isn’t needed when applied to now current designs. And some new parts technology *may not retrofit easily into older engines despite apparently fitting mechanically*. Prudent selection of which materials work well with specific processes used in engine re-manufacturing is critical for successful power production and longevity. Prudent selection is made by understanding history and changes from an evolutionary perspective. It also includes quality control inspection against known engineering standards - weights and measures. In our worldwide parts production industry manufacturing standards are often conflicted and obscure.

Oil, as a fluid in engine bearings, has two main functions; Lubrication and cooling. We have a tendency to focus on lubrication and “fixing it” by implementing falsehoods about how that happens, while forgetting about cooling. So I’ll pose a historical scenario and question why that works as a lead in to modern design practice.

In the 1930’s and prior years many engines used dipper cups, splash, or vapor mist oiling for all bearings and friction points. There was no oil “pressure” as we know it today – zero - because there was no pump or circulations system. Yet these engines were capable of 2500 RPM and sometimes more, while producing a wide range of horsepower outputs, including some supercharged applications. How did oil at zero pressure prevent metallic contact failure? The answer is capillary action as applied to the load capacity film strength of the oil. Let’s do some abbreviated, approximate, and very shallow math analysis. 
Assume a crank rod journal size of 2.123 and a bearing ID of 2.125 by .75 wide. The difference is oil clearance of .002.
That yields a circumference for the crank of 6.67inches leading to an area of 5.005 square inches.
Calculating a circumference of the rod bearing is 6.68 inches leading to an area of 5.010 square inches.
The difference in area being .0055 square inches then leads to a volume calculation of .0055 x .002 yielding .000011 square inches oil space volume. This converts to .00018 cc’s of oil in the bearing. That isn’t much to provide cooling and load capacity so intuition says it needs to be circulated rapidly so it doesn’t absorb so much heat it chemically breaks apart into components no longer acting like oil.

While dynamic running pressures against a connecting rod vary quite a bit for many reasons 1200 to 1750 psi in the combustion chamber is a good starting point for conversation and a “bench racing” calculation. In a 4 inch bore engine the piston has 12.56 square inches of area [3.14 x (2x2)]. That leads to calculating a connecting rod load of 12.56 x 1500 (average peak pressure) of 18,840 lbs. That is quite a big number.
Assume one half of the upper half of the bearing carries the combustion pressure load. This assumption is offered in place of calculus based on the geometry of the rod. Think- the lower half of the rod bearing isn’t in compression because it is below the load centerline. Just the upper half carries combustion generated loads. Of the area in the upper bearing half, a point at the top could be considered to carry the entire load while points at the side carry none of the load (being in slip sheer instead of compression). In actual fact that point load is spread out by the oil film so about half the area of the upper rod bearing carries combustion loads in an off TDC position.
Calculate half of 2.658 square inches to remove the lower part of the rod big end, and then half of the remaining upper bearing to find the load carrying portion, leaves .6645 square inches to carry 18,840 lbs. This very approximately allows calculation of load on the oil film. It is then 12,519 lbs. per square inch.

The following excerpt from “Machinery Lubrication”, in an article by Robert Scott, illustrates this point.
“….The mean pressure in the load zone of a journal bearing is determined by the force per unit area or in this case, the weight or load supported by the bearing divided by the approximate load area of the bearing (the bearing diameter times the length of the bearing). …… Automotive reciprocating engine bearings and some severely loaded industrial applications may have mean pressures of 20.7 to 35 MPa (3,000 to 5,000 psi). At these pressure levels, the viscosity may slightly increase. The maximum pressure encountered by the bearing is typically about twice the mean value, to a maximum of about 70 MPa (10,000 psi).”

It is my opinion oil pressure developed by the engine’s pump, wither it be 45 or 95 lbs, when delivered via a .250 dia. feed hole isn’t going to counter balance that load without other factors being involved. So why have increased oil pressure? And why is there so much effort put into raising it? What are the other factors which really make an oil film lubricate a bearing? 

A great article on rod loading is found at:
http://www.eng.utoledo.edu/mime/fac.../2006JMESShenoyFatemiVol220PartCpp615-624.pdf It is titled:
“*Dynamic analysis of loads and stresses in connecting rods*”
P S Shenoy and A Fatemi Department of Mechanical, Industrial, and Manufacturing Engineering, The University of Toledo, Toledo, Ohio, USA
The manuscript was received on 25 June 2005 and was accepted after revision for publication on 6 February 2006.

And an article covering how the oil film works is found at:
http://scholarworks.rit.edu/cgi/viewcontent.cgi?article=1006&context=theses

Rochester Institute of Technology RIT Scholar Works Theses Thesis/Dissertation Collections
8-8-2013 It is titled:
*Analysis of Connecting Rod Bearing Design Trends Using a Mode-Based Elastohydrodynamic Lubrication Model* Travis M. Blais

At the risk of doing a huge disservice to the scholarly papers’ authors, and by adding my historical perspective to their technical findings, our discussion of increases in pressure for bearing lubrication can be summarized in the context of my questions:

“Hot Rods” in the prewar era were melting babbitt bearings so needed to improve oil flow for cooling. The quickest and cheapest method to do that was shimming or changing their oil pump pressure relief springs to a higher value. Increased pressure correlated to slightly increased flow but also allowed increased bearing clearance while maintaining a functional oil film, which clearance was a far larger factor in increasing flow and cooling. Bearing clearances were then increased until their OEM pumps and available oil formulations could not maintain an oil film inside the bearing. Balances between oil film load capacity, heat removal from the bearing, running clearance, and pump output were discovered by trial and error. Successful operation could be favored by higher pressure, but at the cost of parasitic horsepower pumping losses and generating unwanted additional heat. Inconsistent manufacturing, variation in oil products, lack of testing instrumentation, and fictional advertising hindered direct comparisons of successful designs.

At this point, the 1930’s to 1940’s, real advances in bearing material, pumps, and oil technology were needed to create higher load and speed bearings for high output engines of WWII. This research continues today which has resulted in modern bearing lubrication at far higher loads and speeds than the 1930’s and post WWII era allowed. Oil pump manufactures after WWII started to market oversize oil pumps in high pressure and high volume versions so hot rod engine builders could tip the balance of a stock lubrication system towards maintaining an oil film when high heat removal from bearings was needed.

However better oils, more rigid bearings, improved surface finishes and higher temperature materials really allowed this advance. But our legacy habits of increasing oil pump pressure to attempt to gain a lubrication advantage persist when we should be gaining understanding, then implementing, modern changes to these other factors to upgrade our vintage engines. In my opinion, we as engine builders, have often placed the minor factor of increasing oil pressure into a role of being a major solution which limits our success in horsepower production to the driving wheels. Much of this information and history came to me over two decades time from Major William (Kelly) Owen, USAF, who among other noteworthy life achievements participated in Indy 500 racing from the 1930’s to 1980’s, and was Chief Project Officer for the Cold Weather Test Detachment of the Proving Ground Command in Fairbanks, Alaska where they tried to make ground support and aircraft engines start, then run at full power in subzero temperatures using various modified fuel and oil formulations. Kelly had retired and became my friend and safety officer when I ran a stock car in the Winston West series. He made the call when I exited my pit area to run or not, and put me into effective communications with Denny Luce who was an A/E Clevetite field service representative. Denny helped a lot of racers back in the 1980’s learn how bearings worked.

An additional factor in oil pump pressure requirements is the effect of stroke on the crankshaft. Think for a moment of the crankshaft as a slinger style oil pump lubricating the crankcase. Oil enters the “pumps” (crankshaft) center along the main bearing feed and is slung out through the rod bearings to the crankcase. If rod bearing clearance and/or the oil exit path from the bearing is larger than the oil feed hole area, and if the slinging force is greater than pump supply volume, then pressure inside the rod bearing will fall to zero and the crankshaft passageway can be sucked dry leading to bearing failure. This is generally called “oil starvation”. However oil starvation failure should be divided into two causes, the first occurs when not enough oil is supplied, the second when too much oil falls or is sucked out of the bearing. This suck out is similar to a process called “cavitation” which isn’t mentioned much in terms of connecting rod bearings, yet is well understood in inlet side design of oil pump systems.

Because lubrication of the crankcase is totally pointless and detrimental to horsepower production, and elimination of cavitation inside the rod bearing by other means instead of increasing the oil supply pressure is a more desirable method of upgrading an older engine, other enhancements should be explored. These observations and comments arise from hundreds of discussions with Gary Hubback of Los Altos CA, Bill Jones of Taylorsville UT, and a score with Allan Lockheed of Bolder CO, who participated as technical advisors and fabricators to teams running high power long track vehicles at Bonneville Salt Flats, in NASCAR, and in record breaking cars all over the world.

This elusive and complex balance between pressure, flow, materials, and clearance was worked on by many prominent engine builders of the ‘60’s and ‘70’s. It was most notably codified by Smokey Yunick in his “10 lbs of pressure for every 1000 RPM” statement. This guideline has taken on far more credence than current day engineering might indicate is needed. In a December 2000 address at the Superflow AETC Richard Maskin was asked what oil pressure his ProStock engines developed by a competitor who said he was having bearing trouble (erosion) at 95 lbs pressure in the 9000 RPM range. Richard replied his national record holding small block engines ran 35 lbs of pressure at above 10,000 RPM and his big block engines had 5 lbs more. Reference AETC 11-13. Technology advances in the 16 years since then have not mandated higher oil pressures, although many people and teams routinely set up engines for 65 to 85 lbs maximum pressure. In my opinion they are giving up power output advantages to be had at lower pressures when other modifications allow that set up.

There is an often spoken adage “don’t rev up a cold engine because its oil needs time to flow into the bearings.” How necessary is this for prudent modern engine management or with a vintage engine modified with modern bearings? In engines of the ‘20’s with dipper cups and splash lubrication I’m sure time was needed to establish capillary lubrication films within the engine. Now, full pressure systems establish those lubrication areas within a few crankshaft rotations taking only seconds of time. This is easily demonstrated with a new engine on a run in stand. Remove the distributor and install an oil pump drive tool. Install a master mechanical oil pressure gauge. Spin the oil pump with a drill motor while watching a master oil pressure gauge. The gauge will jump to full pressure within a couple of seconds indicating the oil galleys and passageways are full. The pushrods take several seconds more to fill. But waiting longer than a few seconds for full lubrication to be established isn’t needed from the bearings point of view.

The phrase “let the oil warm up before demanding full power so it can thin to flow everywhere” is also common folklore. I’ve looked into engines when they are very cold (below freezing) to see if oil is flowing to upper valve train areas or restricted from temperature. I’ve always seen oil flow within a few seconds from start up on normally running engines when lightweight modern oils are in service. This is also easy to test. Get a piece of plastic ¼ inch tubing 10 feet long, fill it with oil, then blow 65 lbs of air pressure down it. Time how long it takes to blow the tube mostly clear. Do that with 10w and 15w oil. It will clear almost faster than you can see it and you can’t tell the difference between the two. Refill the tube and freeze it in a refrigerator. Redo your blow test. There won’t be more than a second or two difference which only equals a crankshaft revolution or two difference. When undamaged engines are disassembled for inspection - even a few months after use - there will still be oil held in the bearings and on piston bores by capillary action. This oil is ready to work instantly when the engine is restarted. Getting oil onto a camshaft lobe is the weak link which takes a few seconds longer. 

My understanding is the additive package needs heat to start working. That heat also drives moisture from the oil making it last longer between changes. This is an important issue but you don’t need to defer driving the car while normal oil temperature is achieved and the additive package starts working. 

Should we think of a traditional oil pressure gauge mounted in the output path of an engine pump as a pressure relief set point gauge? The moment an oil pressure gauge stops rising the pressure relief valve has opened. Further increases in pump speed simply dumps oil, heated by compression in the pump gears or vanes, back into the oil sump. It doesn’t even get into the filter loop. This is lost horsepower. Many engines achieve full pressure by 2000 RPM but are raced or run at far higher speeds. Reduction of pump capacity may be indicated after testing and specific research, while improvement in oil system circulation return deserves even more attention in older vintage engines.

The V-8 block engines we are rebuilding today from 50 - 60 years ago had oil capacity issues. Most performance designs from the OEM would hold 6 or 7 quarts of oil. The distribution at 5000 RPM was approximately one quart in each valve cover and 2 quarts in the valley under the intake manifold, and as much as half a quart in the timing cover. This left only 2-3 quarts somewhere in the sump for the pump to intake then pressurize. Many engine builders fitted oversize sumps to “correct” this issue. In my opinion, improving oil flow back to the oil pan may have had a better overall return in investment, as seen in many European and Asian engine designs. They led the way in implementing crank scrapers, oil pan baffles, and low capacity high performance oil pan systems. 

And an additional related issue leading to mistakenly raising oil pressure occurs when an oil pump momentarily draws air instead of liquid oil. For some small period of time thereafter some portion of the engine will be “lubricated” with air foamed oil causing damage. If oil pressure is raised this interval of time will be shortened and damage reduced. However a better solution would be elimination of any possibility of air induction into the pump. 

I believe oil pressure should be thought of as a catalyst in formation of a lubrication film, not the principal force enabling lubrication, which is a property of the oil and geometry of the bearing. Once an engine has enough pressure to create and maintain an oil film, more pressure is detrimental. A watchmaker will lubricate bearings with a needle to which clings a drop of oil. When the needle is touched to the bearing, oil instantly flows into the bearing clearance and will stay there for decades separating and protecting those surfaces without input of any pressure energy. The Holy Grail of hot rod lubrication is zero friction, zero pressure, load carrying bearing systems. I believe high oil pressure is just a crutch we need to have fun running our cars today, while we figure out how to build engines with near zero pumping losses. I believe some builders have progressed along that path further than others.

However, I’m reminded of an occasion at a PRI trade show some years ago where Smokey Yunick was promoting “Prolong Oil Supplements”; additives alleged to reduce friction so effectively the oil could be drained from the crankcase and the car would still function. Prolong had bought a new Dodge Viper, treated it with Prolong, drained the crankcase, then had a famous race driver (I believe it was Al Unser) hot lap the car in a TV ad. About a half dozen of us cornered Smokey for lunch at a table asking him what happened to the Viper….. After giving us the promotional pitch in a few different ways and our continued pointed questioning he finally broke out with “what the hell do you think happened with no oil”. It was a fun day to be there for that “‘revised” marketing pronouncement.

(Ladd) With this background information posted I’ll go back into Roger’s email threads to make specific comments in red mixed into Roger's text in black.

(Roger) I got into the rear main seal. Glad I did. The lip is disintegrating, with a couple of nicks here and there, and it feels very brittle and hard. I can’t remember how old the gasket set was when I assembled the engine, I guess it could have been on the shelf as much as a year. Then the completed engine sat in its frame for nearly two years due to unavoidable delays and I guess this combined is what has caused the problem. This is very odd and I’ve not seen one go like this before. I usually clean with a lint-free paper wipe, no solvents, install and then apply a lubricant (oil, assembly lube) before laying the crank in place.
(Ladd) This isn’t normal. I have neoprene (or whatever that material actually is) rear seals from old gasket sets that are 15+ years old and have worked fine. And when you think about it, seals in service last for longer than that. If you are seeing hardening to the point where it actually feels too hard then I’d suspect some chemical action or heat changed the seal material. Did it get near or in carburetor cleaner? That is a big no-no for seals.

(Roger) So, it’s a couple of days of very careful cleaning before it all starts to go back together again. I have a new standard Melling oil pump and pickup to go in (using the ‘old’, 200-mile, ARP heavy duty drive shaft), even though the ‘old’ pump has only done 200 miles. I thought I’d take that precaution even though everything is new. As usual I have stripped and measured the new pump as I trust myself more than whoever put it together. 
(Ladd) I’d have no hesitations reusing the old pump. It is qualified now as a known good part, not hurt in any way from 200 miles. The new pump may be defective – or calibrated differently- so has less value towards solving a mystery because it introduces new variables. And the new pump will shear off metal bits breaking in that the last pump has already rid itself of.

(Rodger) The pressed-steel sump (oil pan?) I have is not a great fit. I should have worried more when I found I had to use a thick bead of silicone on the pan side of the gasket for the entire surface that fits around the rear main cap - with the pan dry bolted-down with rubber gasket in place, you could see plenty of daylight through the gap where the curved section should have been compressed. I have another that I have dry-fitted to a spare block and it is very much better, so that is this week’s job.
(Ladd) Oh my. This is serious parts mismatching and can lead to oil system problems. The rubber seal on the main cap depends on compression against the cap to seal between it and the cap. A leak will occur despite bonding of the silicon to the rubber and silicon to the pan metal if there is no compression against the cap.
A “thick bead of silicone” in that area is also contrary to good engine building practice because it can break off. If any of the silicon is “missing” from your bead upon disassembly it would be wise to strip the entire engine oil galley system looking for it. Start in the oil pump inlet screen. From there, look in the oil pump relief valve. Then some may have gone into the filter or cooler plumbing which is usually the end of migration for a modified oil system. I say “usually” knowing I’ve found bits of silicon in the ends of pushrod tubes plugging up the rocker arm feed holes. I wonder how those gobs of silicon got through a lifter body but they did. If your system doesn’t have a plugged oil filter pressure relief hole (and there is little reason to block that hole in a stock system) then the silicon gobs can go anywhere in the engine.
I’ve had a few oil pans that didn’t fit too. That is so vexing and troublesome I’ll sometimes make a pan or modify one that fits the rails and end seals nicely to avoid buying one. There are early and late pans that fit the engines in non-interchangeable ways.

(Roger) Latest brief update - Popped the engine out today, mounted it on the stand and rolled it over - it’s not the oil pan, it’s the rear main seal. I don’t know why a new one has failed so soon. There has been a spectacular leak since the first trip out, which is now unsustainable, ½ pint in 50 miles with oil dripping from everything. It’s radiating out from the crank but luckily has not got on to the clutch. I can see that the faces of the pan gasket are dry so that has been doing its job.

Odd, because I used a two-piece seal offset by around ⅜” with a small dab of RTV on the ends, and a light smear of RTV on the cap faces too. Lubricated with a bit of assembly fluid on installation. I have a PCV on one valve cover and an open breather on the other, so I’m not sure why it’s failed.
(Ladd) Let me interject here a few comments about how important proper PCV and KV systems are. Going back in time; before very early days of “modern” crankcase ventilation, prior to the 1960’s, there was one system. “KV” stood for crankcase ventilation and it was comprised of a road draft tube and vented valve cover breather cap(s). The system was designed to evacuate the entire volume of blow by gasses at maximum engine speed by way of venturi action of air flowing over the end of the road draft tube from vehicle velocity. It was vented by valve cover “breathers” allowing entry of “clean” under hood air into the engine. It was understood blow by gasses and fumes from burnt oil were detrimental to engine lubrication so needed removal.

If the vehicle was stopped nothing happened- no venturi suction- but hot air convection might allow reversed flow out valve cover breather(s). This led to all sorts of folklore about determining engine condition by observing where and when oil smoke appeared. Because nothing happened at idle, and Army tests showed the single biggest operational wear factor for engines was dirt inducted by “open” unfiltered KV systems, two changes were made starting in the 1940’s. By the 1960’s they evolved into the *Positive Crankcase Ventilation (PCV) system and a new Crankcase Ventilation (KV system).*

In the Positive Crankcase Ventilation (PCV) system idle speed quantities of blow by were reintroduced into fresh induction air by way of a small metering valve, and the road draft tube (KV system) was sealed or removed in conjunction with a *new system of the same name* venting valve cover breathers to filtered low pressure air in the air cleaner body. *There was a distinct purpose to each system, a high speed one, and an idle assist system, but both depending on low pressure from manifold vacuum for effective operation*. By the 1960’s systems orifices’ and plumbing hoses were sized for 200 to 300 CID engines producing 100 to 200 horsepower and blow by commensurate to those figures for “normal engine conditions”.

Why do we often use the same size orifices and hose sizes on 300 to 400 CID engines producing 300 to 500 horsepower today? Why do we, in some hot rod applications, remove these systems entirely? Or don’t connect the high speed (off idle) KV system to low pressure so it works as designed? It is well understood 7 lbs of negative crankcase pressure is a near optimum value for increased ring sealing in dry sump oiling systems, so why do we run our wet sump systems at just near zero or positive pressure with similar ring packages? Induction charge “purity” is a minor factor compared to gaining cylinder sealing improvements. In my opinion every effort should be made to lower crankcase pressure and promote evacuation of blow by gasses from the crankcase into the valve cover area without heating engine oil excessively. Co-mingling and heating of oil from blow by occurs primarily in the crankcase and lifter valley area so a focus should be made on understanding flow patterns in those regions of an engine to promote separation of gasses from liquids. Valve guide lubrication is a secondary benefit of proper PCV and KV system operation. 

(Roger) I’ve stopped work for the night but will loosen the mains caps and remove the rear one tomorrow to have a look at the seal itself. I should be able to change it with the motor on the stand - I don’t want to remove the crank, as that would mean disturbing the heads and pistons etc. The question is, why did it fail, though? We shall see (hopefully)!
On 21 Jun 2016, at 19:56, [email protected] wrote:
Roger, could I ask you to hold off on re-installing your engine until I get a chance to tell you how to test that seal for sealing while on your engine stand? Thanks, Ladd

(Ladd) A few years ago I did some engine program work for a team running a Toyota off road truck. They were switching from a 22R series 4 cylinder engine to a 5VZ-FE series V-6. A prominent area builder had created this race engine which was sold to that team based on some unbelievable dyno sheets. My job was to reverse engineer their engine and report back my findings. Then get it to make somewhere close to the advertised dyno numbers. I achieved about half the power the other shop claimed, but the truck with my engine design was much faster and more competitive. They could lead races. However they didn’t have a PVC system which would transfer ahead so neglected to install one. At racing speeds the engine started blowing cam and crank seals out of their housings causing massive oil leaks. I helped them build, then get a PVC - KV system installed and working, but rear main oil seal leaks persisted that were difficult for their team to troubleshoot. Eventually I discussed, and then showed them how to check a rear main oil seal on an engine stand before it is run.
This method is from an old 1960’s A/C Delco emission testing manual and can also be found in Cummins diesel engine service publications. First you fully assemble the engine with all covers and manifolds in place. Then you block known leak areas like road draft tubes, crankcase breathers, oil dipstick tubes and so on. Then you pressurize the engine to 3-4 lbs with air and spray the rear main (or any other gasket area) with soap solution looking for bubbles. Remember the engine will not hold pressure. It will leak down past the rings and valves so air will be lost out the manifolds. This is normal, but fizzing or bubbles at seals and gasket interfaces indicate a site where oil will be lost from the engine in service.
On old Pontiac, Ford, and other engines with dual valve cover standpipes for breather caps it was very easy to simply cut a bicycle tube in half, hose clamp each end to a valve cover standpipe, and then use the tube’s fill valve to pressurize the engine. I’m sure you can invent something similar for your Cobra. I’ve also used the oil dipstick tube as an air pressurization point.
A bit of trivia from Caterpillar engine company is their engine paint denoted as “Old Caterpillar Yellow” contained lead and other additives designed to seal gasket oil leaks externally. My understanding is workmen on 1970’s engine assembly lines were directed to liberally paint all engines on all surfaces to prevent leaks. Heavy painting as leak prevention against warranty claims was also taught and practiced at the Cummins engine training facilities when I attended there in the early 1980’s.

(Roger) On Tue, 21 Jun 2016 19:50:38 +0100, [email protected] wrote:
I have stopped using Felpro since I had a very odd coolant leak on the Mustang’s intake manifold 8 or 9 years ago. The built-in silicone elements of the gasket had kind of melted, leaving coolant dribbling down the front of the engine, very hard to spot where it was coming from. Luckily it did not go the other way into the lifter valley. I only use Reinz now and have had no problems at all with them.
(Ladd) All gasket manufactures had leak problems with silicon “O” ring gaskets in the late 1990’s early 2000 model years. It was caused by incompatible chemistry in antifreeze. The debate continues today long after antifreeze use charts have been published by major manufacturers and gasket manufactures have changed the formulation of their gasket materials. A portion of that problem was different vehicle standards for coolant applications in a worldwide market.
All of the reviews I’ve read about gaskets from Victor Reinz are positive.
Kevin
*From:* [email protected] [mailto:[email protected]]
*Sent:* Tuesday, June 21, 2016 11:26 AM
*To:* [email protected]
*Cc:* Kevin Schofield
*Subject:* Re: Oil leakage
(Roger) Yes, I think the synth is the best option. I did remove the crank with head and pistons in place, and even gave my dear wife the privilege of being involved - she guided the (appropriately protected) rod bolts around the crank journals during replacement. I’ve put a two-part seal back in, a Reinz brand new one, ⅜” offset and a tiny bit of RTV on each end and on the cap mating surface. Can’t get rope seals in the UK, and I’ve long lost the pin from the rear main cap.
(Ladd) I believe you need to check a couple of other things too.
A quote from Albert Einstein is “insanity is doing the same thing over and over expecting a different result”. When I hear of people replacing a rear main seal over and over again I have to wonder if there might be some other cause for a leak than being mis-assembled.
I know many tens of thousands of rope rear main seals have been replaced with updated lip seal style neoprene assemblies. However when the rope seal engines were produced manufacturing tolerance of the rope seal area were not very tightly controlled. Manufactures counted on the rope seal material to conform to any geometry their tools cut. Now, decades later, seal manufacturers are making a “standard part” which might not conform to the block and cap tightly enough to create an oil proof OD seal while being perfectly acceptable on the ID against the crankshaft. Yet they feel “OK” sliding into place. Or the concentricity of the rope seal area may not be centered well enough for a lip seal to function. And the new seals themselves may have excessive manufacturing tolerances on the OD because they come from plants all over the world that each does some details a bit differently. Perhaps these issues are root causes for oil leakage falsely blamed on joint offset or misapplication of gasket sealer. I may be incorrect in saying no OEM offsets lip seal gaps in production. I believe it is a service procedure, sometimes of limited value, because if the OD crush of the seal is reasonably correct its ends will butt virtually oil tight and do so without any additional sealer.
In most engines the rear main cap has a large window for oil drainage off the bearing. Unless that window is blocked by a mis-fitting oil pan, gross misapplication of silicon sealer, or dramatic over filling of the oil pan; oil pressure coming out the edge of the bearing falls to zero within a few thousands of an inch of the bearing edge.
The crankshaft has a slinger ridge which guides oil from the bearing’s oil exit area into the drain window. Its forces of operation are parallel to the rear main seal lips so don’t contribute energy to the oil in a way to force it past the seal. Space between the oil slinger cavity and rear main seal is mostly empty - free to drain.
If the bearing pressures on the oil are relieved before it gets to the seal what moves the oil across a blocking seals lip? What adds pressure to the oil so it seeks a lower pressure area outside of the engine?
A general answer is crankcase pressure from blow by gasses. This may be true and is easily tested. However leaks persist even when this possibility is reasonably eliminated. I think it is wise to consider the possibility some pumping force created in the space between the crankshaft slinger and lip seal in the engine overhaul process acts on the oil so very low or perhaps near zero crankcase pressure becomes enough to cause an oil leak that didn’t exist before. Or a leak that the more robust rope seal closed successfully. 
I suggest checking and correcting the length and sealing quality of new replacement flywheel bolts may lead to stopping oil leaks in the vicinity of rear main seals. I believe if that bolt is too long it will grab oil in that cavity and spin it around just like a rotor vane pump does. The “pump” inlet is the slinger exit area while its exit is the drain window and the upper seal area which becomes packed with oil waiting to drain out the window. Bolts that are too short cause a similar but less intense pumping action because of the void in the crankshaft threaded sections. This will be an RPM speed sensitive leak.
When we tested the Toyota team’s engine it had signs of oil radiating from the crankshaft on the flywheel clutch side. A bubble test showed leakage out the bolt heads. No sealer had been applied to new grade 8 bolts purchased at an industrial supply house instead of getting OEM bolts that had sealer pre-applied, a flat shoulder under the bolt head, and are “one time use” fasteners. Sealing the bolts was an easy fix for something that had vexed their team for many months.
(Roger) On Tue, 21 Jun 2016 18:27:06 +0100, [email protected] wrote:
I like this idea of personal tech service at a high level, I might get used to it.
(Ladd) Hi Roger, It is a good thing to do for me and for you. About a third of my income comes from consulting now and I've met some really interesting people doing some pretty interesting things. I hope you figured out that the crank can be removed with the heads and pistons intact in the block. I'd put in a rope seal. I'm writing on a longer explanation now. Go for the synthetic oil. Don't be afraid and never look back. Lol. Ladd

(Roger) I’d have to say that top of my list of questions is, should I go to the full ester synthetic now (200 miles), and not worry about the ZDDP on the flat tappet cam?
Whilst replacing this rear seal, I have been through the engine completely and it looks great. It is a tribute to your skills, Ladd, that everything fits so nicely and neatly and all the bearing surfaces have such a uniform polished pattern with no signs of scuffing or uneven wear. I can live with the oil pressure, although I’d expect it to drop a little bit more with a full synthetic. Roger
(Ladd) Thank you. I appreciate your work in my shop and conversation about the things we do. I believe you can see that traditional issues of engine break in, bearings, gears, chains, and valve train have already “broken in” in less than 200 miles. I think in other emails you have said the engine runs smoother than any V-8 you have previously owned so my guess is the rings and cylinders are working well also. As I mentioned elsewhere this engine was prepared with modern methods and parts so would “break in” very quickly, say in less than 10 minutes or 50 miles. So go for the full synthetic oil. Don’t hold back.

In the early 2000’s I went to a technical conference sponsored by Joe Gibbs racing where oil (among other things) was discussed in detail by Lake Speed Jr. Of the professional engine builders there we all had lost a few camshafts to lubrication failure in prior years. ZDDP was discussed and we were assured the Joe Gibbs product had enough to meet our needs “off the shelf”. This was possible because of a loophole in the EPA laws for small quantity manufacturers of specialty blends. It was also possible because different standards existed for HD truck oils than passenger car lubricants. A consensus was quickly formed that Shell Rotella and Chevron Dello diesel truck oil were acceptable alternatives to expensive additives. And later on I learned that Redline and Royal Purple products were “correctly” formulated for applications with high camshaft to tappet loads. Whatever the equivalent products are in the UK will work fine. I kept your spring tensions low deliberately so troubles would not darken your doorway but provided a set of race springs in case you wanted to push your RPM limit up to 7000 after a while.

(2022 update: Since 2000 the market has changed again and oil additives for ZDDP are necessary again, both for break in and for service. Red line and Lucas products when added to quality oil will meet older engine’s needs.)

I am also reminded of a 1980’s conversation with Henry Styers, then the western region head GM training instructor about small block camshaft failure. I’d made some cocky comment about being able to fix any cam problem GM cars had – just send them over to my shop and I’d put new parts in from aftermarket sources. Whew- big mistake. He turned around and told me the problem was bigger than GM so who was I to mouth off that way about things I didn’t understand. I believe he’d been an Air Force DI, then officer candidate instructor in WWII, so his attention to disarming my cocky attitude was detailed, complete, and expertly done with the grace of a southern gentleman.

I learned from Henry GM was fully aware of camshafts failing because of oil issues some years prior because they understood where government regulations had driven the oil industry, and were already testing (roller cam) valve train durability extensively. GM’s quick answer was an additive sold over their part counters and provided to dealership mechanics when replacing engines. He also told me GM produced some blocks where the lifter bores were not angled correctly which caused failure. These were being quietly replaced under warranty. He denied any metallurgical issues with cams and lifters themselves. Henry ended on two points. First, whoever makes a car part can do it anyway they want to – it is their right to innovate, but the market would tell who did the best job, and he believed GM was the premier car company so had the best parts. Second that my invitation (as an independent mechanic) to attend a single training class was extended indefinitely at his personal recommendation. So I attended GM school as often as I could until Henry’s retirement in 1983 by which time I’d attended nearly every class offered.

(2022 update. GM no longer is allowed to sell it's engine oil additive. It has been out of stock for several years now )

Henry’s passion for all things GM was counterpointed by knowing Orion Yando’s passion for all things Ford. Mr. Yando was Ford’s western region general manager. He handled all of Ford’s dealer issues west of the Mississippi river and out through the Pacific Rim. I attended High School with his son Dick so observed first-hand how dedicated he was to advancing Ford products when occasionally in their home. Later I attended Ford Industrial engine school finding the quality of teaching staff excellent, and similar to GM school. A take away lesson is, passion for a company’s product and detailed knowledge of the product go best when delivered hand in hand.  

(Roger) I have a question on oil pressure. We went with std main bearing shells on the crank, and you gave me the options of building the rod bearings looser (all std) or tighter (std and +1thou) or tight (all +1thou). I have gone with the tight option, using the oversize shells upper and lower in the rods. I’ve now done around 200 miles in the car, but the oil pressure seems a little low at 20psi hot idle (650rpm) and 45psi hot at 3000rpm. I’d welcome your thoughts on this, although I know these are acceptable figures for a small block Ford.
(Ladd) I read in some forum posts how you struggled with lifters wondering if they caused your lower than expected oil pressure. Your focus seemed to be on the oil passage band around the tappets center. My understanding of how that band works follows:

It needs to be wide and deep enough that full oil flow and pressure can be passed the entire length of the engine oil galley. And there needs to be enough capacity in the band area to feed upper valve train components more or less equally through a hole in the tappets side. The depth of the band is limited by the diameter of the plunger inside the tappet vs. the body OD vs. strength of the body wall so it doesn’t break in half. The width of the band is limited by the geometric relationship of camshaft base circle diameter vs. lobe lift vs. length of the block’s bored tappet holes. Within these parameters the oil band can be located anywhere it doesn’t overlap outside the block tappet bore.

If the tappet drops too low (towards the camshaft) exposing the band to crankcase volume you will get a high pressure internal oil leak of about the same magnitude as leaving the crossover galley plug out. However the band’s recess will enable side loading from camshaft rotation to nibble at the block’s bore on every reentry. This will go on for a few hundred cycles until the tappet jams in the wallowed out bore, breaks the camshaft while blowing a piece out of the block, and maybe snapping the timing chain. I don’t think you had this problem. If the band comes above the block tappet bore a similar leak will occur but those consequences might be much less dramatic, or not. The tappet will hang up a little bit on each reentry maybe making a bit of a noise. It will take smaller nibbles out of the block but eventually will jam causing that valve to hang open. The open valve may hit a piston which will get your attention. In either case a high pressure or high volume oil pump might mask this issue visually on a gauge for a while.

I check for tappet oil band fit by inspection in the block. Very early in the assembly process I trial fit a tappet into its bore deep enough to expose the band to the camshaft tunnel. Then I hold it there with a small copper jaw welding clamp and measure the distance from the top of the block bore to the edge of the tappet body. Subtract .060 or more from that depth to determine maximum tappet drop. Then reset the clamp with the oil channel band exposed at the upper edge and repeat the measurement and calculation.

The camshaft must not drive the tappet past either limit. *And the oil channel band must not move so far up or down as to allow the tappet body to block off the oil galley*. This is something easy to see by looking down the galley bore with a flashlight. This design favors a wide tappet oil band channel. If the tappet body blocks the galley bore it will not show up by measuring maximum oil pressure at the OEM gauge location, which is ahead of this tappet system, because the pressure relief valve is open. Often times an oil galley bore is offset enough the tappet body cannot ever block it. This design favors a narrow tappet oil band channel. If your parts selection “passes” these inspections then oil leakage and flow will be “normal” no matter who manufactured the tappet or camshaft. Problems arise here from non-standard base circle camshafts.

Oil leakage past the tappet body is important to understand. It can be calculated in ways similar to connecting rod clearance but we don’t know how much oil actually flows past the calculated space so this is a comparison of clearance volumes, not gallons per hour. The Windsor Ford tappet is .874 dia. (smallest) and .8745 dia. (largest) Manufacturing tolerances are very closely held so anything outside this range should be rejected as a defective part. If we accept .0027 as a clearance wear limit, oil at the tappet needs to pass a .048 cc clearance space. Circumference = 2.75 inches, passing approximately .200 inches twice (upper and lower tappet bearing areas) at .0027 clearance. Sixteen tappets would have .768 cc’s clearance volume – not much considering pumps are rated in gallons. However tappets erupt a literal caldron of oil into the engine valley area in operation which needs to be returned to the sump as rapidly as possible through oversized drain holes then scraped off the cam and crankshaft. Or directed en-mass to the blocks ends for return to the sump.

Pontiac knew this and opened up the block casting so far it is felt to be weakened compared to other manufacturers (for large roller or high acceleration rate cams) inducing flex related failure of the tappets and bores, but it does allow plenty of return oil flow onto the cam. This block weakness has been corrected in present day aftermarket Pomtiac blocks but can be addressed in vintage OEM blocks by machining a plate to fit a re-machined Pontiac valley casting which is permanently affixed into place with structural epoxy and bolts. I believe this modification was explored by Mickey Thompson in the 1960’s and recommendation related to me by Ed Iskenderian in the early 1970’s when I was buying performance camshafts to modify my GTO. Ed would actually answer his phone at the grinding shop and we could chat about how to make my Pontiac run better. 


(Roger) I am concerned that as the engine beds in these figures may go lower. I’m running a mineral 20W-50 (high ZDDP) to run in, but was planning to go to a 15W-30 fully synthetic later. I think that may show an even lower pressure though, so may stick with the mineral. I’m a born worrier, as you can see!
(Ladd) Pressure drop with full synthetic oil is normal. Viscosity standards for modern oil and modern synthetic oil are different than standards for the 30w we grew up with. I believe the words of art used by petroleum companies are “equivalent protection level” when marketing those products. That has very little to do with actual viscosity. It is a common misconception it might. And it is a misconception hosted by manufacturers needing to meet a fuel economy number – not because it can allow an engine to last longer.
If you were to take a can of vintage oil and pour it out next to a stream of modern oil of the same advertised rating the oil from the new can would empty far faster. It will run through an engine bearing far faster too which is why it will show a lower pressure indication. But its load carrying capacity is slightly greater so it works, *if not degraded*. This is a point many people miss. Fuel dilution ruins multi weight oils faster than single weight products. Those oils were developed for fuel economy and minimal pumping power losses with a side advantage of cold weather – far, far below freezing weather - rapid initial circulation lubrication, not for any advantage in more normal climates.

Each vehicle operator will have to decide which oil viscosity danger is more important to protect his engine against, a cold start over rev before the engine has full oil pressure and circulation; or fuel dilution from a carb that isn’t quite right or sticking choke or PCV / KV system not balanced correctly. 

I like synthetic oils a lot for high temperature protection but their multi viscosity part isn’t needed until far below freezing. So I’m not certain you need multi-weight oil at all, while also being in the position of not being able to buy single weight full synthetic oil easily.

I’m glad you set your crank up to the tighter specifications. The photos of your plastic gauge are ok. There is modest controversy about its use. When I started using it in the 1960’s the directions were to apply it to clean and dry bearing journals for the most accurate reading. That was problematic in my opinion because what you are trying to figure out is clearance in an oil film, not air clearance dry. And putting plastic gauge in dry created a problem getting it out again. I was always getting a dirty finger nail in there against a very clean crankshaft which bothered me a lot. Not to mention how I felt about scraping it off a new bearing shell. So now, a few hundred feet or so later into use of that product, I always put it against an oil wet crank. I noticed your pattern was a bit short too. I’d use a longer piece so it lays over the bearing shell edge on both sides. Seeing taper in a journal with plastic gauge is possible, but so is seeing a twisted rod, bent rod, error from torquing the rod cap (which unavoidably pressures the journal so the plastic gauge needs to be placed at 90 degrees to the cap parting line) and a couple of other bad or possibly illusionary things. Measuring bearing fit with a micrometer has limits of about a half thousands realistically, which is the same as plastic gauge. My opinion is both options have a great place in engine building but don’t trust either one on its own to be a final indicator. And I’ve nearly given up getting plastic gauge out. Just leave it in there. It is low temperature material so vanishes when an engine is started doing far less damage than the dirt under my fingernail might.

I noticed in a forum thread your idle speed was 650 RPM. That is too low. Light oil will not pump well at that pump speed. Too much pump spit back and not enough inertial flow to keep the inlet full. Remember your oil pump runs at half crankshaft speed. And it depends on RPM to keep pluses and flow going smoothly. Bump that idle speed up to 800 or so. Everything will work better. I’ve noticed many modern engines using light oil have pumps running at crankshaft speed. There are reasons for doing that which we need to think about before we run light oil by just pouring it in older engines.

I noticed in a forum thread a comment about 360 degree oiling not being necessary on a Windsor small block. I agree, but pose these questions: What happens when the oil passages at the main bearing shuts off every 36 degrees (180 degrees divided by 5 main bearings) sending a pulse echoing back to the oil pump? And what happens to cavitation of the rod bearing when smooth flow is interrupted? I think the answer is nothing good. Which leads to another question: why didn’t Ford put in 360 degree oiling from the start?

An echo back pressure spike will rattle the pump gears and rattle the pump drive which can rattle the distributor gear drive harmonically. All that is part of the nothing good answer. An interruption of pressure and flow to the rod bearings means energy is dissipated doing no good while energy is later needed to restart that flow to get back to whatever level it was at. This is wasteful; and risky if conditions are marginal. Ford made a choice about their main bearings. A 180 degree oiling channeled upper shell could supply the rod bearing for stock use. The 180 plain shell lower could carry more combustion chamber pressure load allowing the entire bearing to be designed narrower and cheaper. So that is what happened. For economic reasons 180 degree oiling was chosen, not because it was a better design. But that was then and this is now. To get from 180 degree oiling to 360 degree feed of the rods takes another $60 main bearing set to rob the upper shells from and 10 minutes with a cut off wheel to re-notch the main web for a modified bearing tang location. The question becomes then: is that security and performance benefit worth it to you?

(Roger) The only thing that was not normal during cam break-in was that the motor got excessively hot - bright red glowing cast headers - which was down to a distributor problem giving retarded timing. Cam break-in was interrupted a couple of times to try to sort this, which was finally achieved with a different distributor. I can’t see how this would affect the crank seal, but all is now assembled again by the book and I will report back on progress.

(Ladd) That kind of heat affects different engines differently. I’d worry that your exhaust valve seats would become annealed, shrink, and fall out. Excessive exhaust back pressure can do the same thing. You’ll know in a few thousand miles about that. Munch-munch and crunch goes the piston top.

Heat in any cylinder head is removed by water and oil and exhaust gasses. Oil from the rocker arm drips down the spring and across the head surface moving heat to the oil pan and out to the cooler from there. Some engines are rebuilt so oddly with high pressure and / or high volume pumps they flood the valve covers (and tappet valley area) and run out of oil in the pan to pump to the bearings. These engines don’t last long so to “fix” that issue some builders restrict oil flow to the valve train knowing roller rockers don’t need more than a mist of oil to function…. More oil stays in the oil pan – sort of- It is just pumped in a circle from pan to pump to pan via the pressure relief valve, while gaining heat. The small amount of oil running across the head becomes super-heated and quickly degrades. That heat and degraded oil hardens *all engine seals over time. None of that is any good. *

Some engine builders went so far out on that limb after restricting oil flow to the valve train and fitting oversized oil pumps and sumps they installed bypass lines and spray bars directed at the valve springs to cool them. In my opinion simple and OEM over oiling the rocker arm cannot hurt anything, but under oiling the valve spring is death for the spring. So my position is; don’t ever add valve train oil restriction, improve oil flow drain back instead.

Evaluation of how much heat goes into a valve spring lower coil from the exhaust port is different for various points in the head. And some heads put the springs in very bad spots for staying cool. I have noticed when testing new spring sets they form a bell curve of pressure distribution. I install them so they do equal work by shimming installed height to nearly equal values +/- .015 then putting the slightly stronger springs found in the bell curve distribution into the slightly tallest remaining positions. This equalizes heat generated by spring compression. I adjust that procedure if I’m using a dual pattern cam. The goal is to make the springs all last an equally long time. If I cannot make a “set” of valve springs from 16 in a box set, I’ll buy another boxful to increase the number of springs in a favorable portion of the bell curve distribution. Isky makes really good valve springs at a racer / hot rod level. Comp cams springs seem of inconsistent quality, but getting better. When those springs are run very hard, hot, removed, and retested a bell curve distribution of pressure has gone away and more random pattern has formed, although sometimes that pattern is distinctly exhaust or intake side denoted. Adding oil deflectors to the top of rocker arms so the lubrication spurt is directed down into the pivot and into the spring coil (instead of up onto the valve cover and wasted) is very helpful. Ford did this on their big block industrial engines, among other manufacturers who also implemented that fix at an OEM level. 
Thanks, Best of luck to you going back together and on the road. Ladd

(Roger) Thanks for all your work in preparing this reference work. It is really helpful and should be there for others to read.
Oh well, it seems we’ve just left Europe - time to get back in the workshop and put politicians out of my mind for a while at least.
I’ll report back, All best wishes to all Roger

(Roger) Dear both {Kevin & Ladd}
well, the engine’s back in and running as sweetly as ever. I’ve done a 40-mile round trip since refitting it and no signs of any leaks so far. I did your RMS {rear main seal} test with the motor on the stand, and there were no bubbles, so fingers crossed! I also checked the flywheel bolt length as discussed: they are ARP bolts which are 5mm short of the back of the mounting flange, so leave a slight cavity here but not, I would think, a significant one.
(Ladd) The faster you turn the crank the more important it becomes.

(Roger) It’s now running on Fuchs Titan Pro R 15W-50 full ester synthetic (used to be called Silkolene), which is what my Mustang runs on. Interestingly oil pressure has improved at idle to around 25psi, with 45-50psi at 3000, all good. It certainly runs very sweetly but I do need to get it on a rolling road {dyno} for carb tuning. That will have to wait until I’m back from Le Mans next week - I have set idle mixture at around 13:1 and am running 55 (Holley sizes, in Autolite 4100) primary mains as the plugs were just a little bit white on 54s. Ignition timing all-in at 34° @ 3000rpm, no pinking so far but the rolling road will iron out the fine detail.

(Ladd) Hi Roger, glad you are running again. I enjoy hearing my tips helped your efforts succeed. I’m not sure why your oil pressure improved. I’d guess the oil which was drained out had a bit different thickness (actually thinness) so didn’t pump the same. If you get a good KV system installed I’d recommend going onto an oil analysis program for a year or two so you don’t over change expensive lubricants while discovering how seldom that needs to be done in today’s vehicles. We found on the IMCA car, even running in the dirt at very high oil temps of 250+ F, Redline synthetic oil would not break down until half the season was past. Dirt ingesting from open breathers was an issue though. In a half dozen other engines I’ve had on synthetic oil, with monitoring, (BMW, Honda, Ford on Mobile I) sometimes unbelievable (to me) change intervals (8 to 10,000+ miles / 3 years) were discovered to be fine chemically. These engines have all gone great distances in high speed/hard service and are on their second or third hundred thousand mile go round without any lubrication wear issues or any “overhaul” service what-so-ever. I believe data gathered in oil analysis can lead to economic savings (and catch early failures) so recommend it while clients get their new engines figured out operationally.

Some years ago when pump gas fuels started to greatly change in formulation several of us listened to Rick Gold from ERC fuels discuss tuning by spark plug color at an advanced engine theory class. I was also listening to Bill Jones views on that subject. My understanding at that time was, several men, including Rick and Bill, were helping Alan Kulwicki with his NASCAR engine program. Alan’s spark plugs would be sent overnight FedEx to Bill who would mill them apart for color inspection, render his opinion, and send them back to Alan so his team could make jetting changes. I saw those spark plugs, examined them, and listened to their opinions carefully.

Several beliefs were formed in me at that time which have held true over the years since. They are: Jetting by plug color with race fuel is possible if the fuel is always the same and you don’t change ignition around or compression, and you relate jetting changes with other weather, dyno, and engine use. Jetting by plug color for pump gas on the street is impossible because the lead is gone which formed the glaze which gave the additives their colors. There is simply too much “white” zone where data isn’t generated by fuel burning on the spark plug. You can select heat range by electrode condition, but that isn’t the same as selection of jetting for mixture.

At that time O2 sensors were pretty new for mixture control – maybe a decade old - give or take a few years. And portable analyzers were pretty much out of reach financially for everyone; so there was a period of time when setting carburetor jetting got really hard to do. It became an issue of experience and sensing what an engine needed more than an issue of looking at information from a spark plug and tuning binder records. Now methodology has changed again.

There are a couple of really good and easy to use portable air / fuel ratio gauges on the market which don’t cost too much. I use that method and like it a lot, but should mention this consideration when setting mixture from an air / fuel ratio gauge vs. a spark plug. The spark plug gave an average reading with its color. It kept you safe if you snuck up on going too lean. The air / fuel gauge gives an instant reading. You can get too lean very fast if you just jump into big changes because the gauge shows some value. This means to me making little thoughtful changes, one at a time in tuning, is more important than ever. But I’m not a “tuner”. There are wizards, scientists, and kids with laptop computers who do that now. 

(Roger) Rear axle unit’s out now as I am changing the gearing from 3.07 to 3.31. I have a couple of days to get the new one in and do a test run.

I look forward to seeing Ladd’s contribution to the forum - this kind of information needs to be published for everyone's benefit.

(Ladd) Ok Roger. That is it for me. I think I’ve covered my build theory and practice more than enough for anyone to wade through. I’ll send this to you first for comments and corrections then maybe post to the forum – let them do as they wish with it. 
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## michaelfind (Dec 14, 2018)

Thank you for sharing


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