# Engine Oil



## SDGoat619 (Mar 21, 2011)

I am thinking about running Amsoil 10w40. Any Feedback ?? 

By incorporating high-quality synthetic base
stocks and a superior high-zinc additive package, AMSOIL Premium Protection Oil exceeds the needs of large and small gasoline or diesel engines in cars, motorcycles, trucks, motor homes, maintenance equipment, heavy equipment, street rods and marine applications. It is ideal for high-mileage vehicles, vehicles with flat-tappet cams and high-stress vehicles subject to hot temperatures, heavy hauling, trailer pulling or off-road use.

AMSOIL - SAE 10W-40 Synthetic Motor Oil (AMO)


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## HP11 (Apr 11, 2009)

My feedback would be: if you don't want to look like a either a spambot or some kind of homer for Amsoil products, don't use 'cut and paste' quotes directly from their site and then link to their site......just sayin'...


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## GTO JUDGE (May 14, 2005)

I stated this numerous times so here goes again:

According to the late John Sawruk a Pontiac historian, engineer and supreme technical adviser for the GTOAA, he advised NOT using synthetics in the older engines not rebuilt for their usage. I was told why but I do not recall the reason. While many use it and recommend it is their prerogative. John spoke on the reasons why not to use them at various seminars I didn't attend but other club members did. People have different opinions on this, for me personally I opt to heed the advise of those like the late John Sawruk.

When I installed my new 3.55 rear I was told NEVER use synthetics in that either. Something to do with the breakdown of the rubber gaskets over a period of time. 

IMO if you insist on using Amsoil synthetics and they recommend it for 40 year old engines I would get a warranty from them in writing and notarized.


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## SDGoat619 (Mar 21, 2011)

Thanks for the info, I did order some ZDDP Plus off amazon. Just trying to get the best oil for these old motors. What brand do you prefer


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## GTO JUDGE (May 14, 2005)

SDGoat619 said:


> Thanks for the info, I did order some ZDDP Plus off amazon. Just trying to get the best oil for these old motors. What brand do you prefer


Any good brand name.... Castrol GTX, Penzoil etc. I change my oil every spring and use AC Delco filters.


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## geeteeohguy (Feb 2, 2008)

Synthetic oil is "better" than conventional oil in that it doesn't coke up and turn to tar if you blow a radiator hose and keep driving the car. It flows better, has better film strength, and has better "cling" , which helps with start-up wear on engines that sit for long periods. If a ZDDP package is added to it, fine. IS synthetic oil necessary? No. Zddp is. I run Diesel spec Rotella T or Delo in both my goats, with zddp additive. I run full syntetic in my 4Runner, because I take it to the middle of the Nevada desert every year, and if it overheats, I need to know I can use whatever life is left in the engine to save my own. I have read in various articles that synthetic gear lube is not to be used with our Muncie gearboxes and posi rear ends: too slippery for the scyncro cones and the clutch units in the posi. It would be fine in an open diff. I've done EXHAUSTIVE research on this oil thing, and though not a lubrication engineer or refiner, I'd like to think I know what I'm talking about. I could be dillusional, though..........


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## Too Many Projects (Nov 15, 2008)

geeteeohguy said:


> I could be dillusional, though..........



:rofl::rofl::rofl:

You made my day, Jeff.....

I go to Wally World and get a 5 quart jug of Mobil 5000 in 10-30 weight for $12. Add an $8 bottle of ZDDP and a Delco filter and you've got what you need for about $28.00.


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## peahrens (Jun 7, 2010)

Suggest to research the ZDDP (zinc) issue here and on Google. From what I've read, the issue of zinc content is very critical for the flat tappet / high performance setups most of our goats have. I expected at first that this was another myth, but with enough research you will be convinced that you want to KNOW that your oil zinc content is 1300 or so, not the typical 800-900 that most oils for today's cars must use to provide increased (by EPA) catalytic converter life (newer cars are ok with less zinc as they've got roller lifters/etc). The zinc level is doubly (super-critically) important in breaking in a new flat tappet cam. 

You will find that some available conventional and syn oils contain the zinc for these flat tappet / high performance applications...check out the Joe Gibbs site, for instance...you can use his engine breakin oil (conventional), for instance, followed post breakin with his conventional or syn Muscle Car oils, both with the needed zinc (and thus specified NOT for more recent cat converter cars). Others here have mentioned I think certain Valvoline oils (maybe VR-1 20/50) or Castrol Syntec 20w50 for CLASSIC cars. 

If you can find the Mobil1 site with the right table, you will note the zinc level is lower (900 ppm) for today's typical Mobil1 10w30, because most use that in today's cat converter cars. But they still make one (15w50) that has 1300 zinc, noted for racing and flat tappet applications. That to me implies the older cars need more zinc, even with synthetics. And you will note the "high mileage" Mobil1's include a tad more (1000) zinc, implying they can add more for cars over 75k miles and still make the converter last the required 150k or so. All of which suggests the 1300 ppm zinc is desireable from a wear standpoint in all cars, but essential in the older flat tappet / hi-po cars, even with sny oil. 

Alternative to buying an oil with enough zinc, you can buy the oil you like and add ZDDP Plus to boost the zinc (don't over-add). I did this with my 4-stroke boat engine...I wanted to switch to a 10w30 syn oil, but all had the lower 900 or so ppm zinc. So I chose Mobil1 10w30 and added ZDDP plus.

You'll find older threads somewhere on this, there are other choices than I've mentioned. You've got 3 questions...oil weight, conventional or syn, plus the zinc level. I've gone to 10w30 syn Joe Gibbs after breakin, but I've got a new Viton rear main seal that I hope accomodates the syn. I wanted synthetic, did not want the higher viscosities, and wanted the right zinc level. Whatever you do, IMO one of the most important things is to attain a minimum zinc content. 

If you have the time and inclination, I suggest doing enough reserach to come to a comfortable conclusion on all the issues.


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## geeteeohguy (Feb 2, 2008)

peahrens, very well stated. No worries on synthetic with your Viton seal...The modern synthetics don't have any adverse affect on seals at all. The "synthetic oil causing leaks" stuff started back in the '70's when the oil was first being widespread, and it did tend to find its way out of potentially leaky areas easier due to its superior flow characteristics. So, if you have a "weepy" area on your engine, it might leak a bit easier with full synthetic, but the stuff won't attack any part of your engine. The point you made about the ZDDP still being needed if you run synthetic is a good one. Many people believe this is not true, and they are mistaken. Also, too much ZDDP is not good as it can accelerate wear. I'm using Rotella 15/40 with a little ZDDP added. I may switch to Brad Penn 10/30. No need to run 20/50 or 15/50 in my engines, even in 100+ temps around here. IMO, 20/50 is for worn out old flatheads with loose bearings and blowby.....too thick for a properly assembled Pontiac V8.


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## dimitri (Feb 13, 2009)

Most engines are built and rebuilt using something like Permatex Ultra Black Hi-Temp RTV silicone gasket maker. These sealants are not made for synthetic oils. You will develope leaks everywhere. I learned the hard way. If you want to build an engine to use synthetic oil you have to use Permatex Gear Oil RTV Sealant. 

This info was gotten by the tech department at Permatex.


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