# 69 GTO not running well...



## dan woodland (Jul 24, 2013)

Good evening all,

I have a 69 GTO with a fresh-ish engine rebuild (approximately 1,500 miles) which is not running very well, especially in gear at stop lights or when reversing (almost stalls). Runs fine when given more gas in all situations.

Background:
Carb was rebuilt a few years ago (maybe 2,000/2,500 miles ago). Car ran great last summer... engine seems to be a bit 'weaker' now, can't burnout/launch like I did last year - driver side wheel mostly. Does do equal burnouts in reverse. Also has a very strong odor from exhaust.

Transmission rebuilt a few summers ago and rear end rebuilt last summer (Posi installed with 3.23 gears). Seems to shift as expected at heavy load or being a "respectable citizen" on the road.

No leaks of great concern other than in the engine bay(need to tighten valve covers etc) and a very slow rear end leak(need to check bolts etc).

Car is stored in the winter (November to April) with fuel stabilizer in the tank - tank filled to the top to eliminate condensation. Storage could be considered heated as it does not get below 50 degrees at any time.

Things I'm going to look at, assuming I am missing something which I hope someone here can help with by pointing it out. Or maybe the order in which to process them.

Maintenance:
1. Vacuum leak at carb or trans actuator line/hose.
2. Fuel pressure/pump or fuel filter issue.
3. Check all vacuum ports/lines etc.
4. Check transmission fluid level/leaks.
Things more complicated or requiring adjustments:
3. Timing issue.
4. Tuning/carb issue.
5. Transmission issue.
6. Rear end issue (not likely).

Any help is greatly appreciated.


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## BLK69JUDGE (Jun 10, 2010)

this conversation will get out of hand fairly fast....
I am just a back yard mechanic .. no schooling just 45 years of wrenchin and a couple hundred cars n truck titles thru my fingers ,,,,my newest is my 88 454 motorhome still carbureated 

K I S S keep it simple simon dad would say 

start with the easy stuff.. 1.. uno.. one thing at a time

time for a set of spark plugs ,,, they will give you a real eye full of how its running,.,,
and how its burning fuel
what sistributor are you running ,,,, what plug is in it now? what are the head castings? 48 16 12 13
pull 1 at a time mark the wire for now with painters tape
and felt pen for the cylinder it comes off ... they are marked on the intake runner,.,,,
a 2" piece so you can make note on the tape also if need be...
pull the plugs ,one at a time,,, put a piece of tape on each plug and label the cylinder,,,,
measure the gap record on the plug ....
gap your new ones correctly for your hei or points ....

they are probably black .wet looking .. wipe your finger in the tail pipe ,,, is it sooty black ?

post pictures of the old plugs...

sounds like a carb issue ... vacuum leak it would idle faster and run lean,,,

time to change oil also and filter with all that gas washing the cylinder walls past the rings

and fire it back up .... then we can move on ....

do you own a timing light ?


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## dan woodland (Jul 24, 2013)

Thanks for quick reply... 

Stock type plugs (new with engine rebuild). I think gap was set.45? (GAPped for HEI) Have a plug cleaner if that helps until they can be replaced.
Pertronix ignition (HEI)
Stock distributor - New gear/roll pin with engine rebuild.
Black soot on/in tail pipes.
Stock Heads
D-port headers
Changed oil and filter today
Yes, I have a digital timing light. Don't recall initial or total time.

So if carb issue what steps do I need to take?
New plugs after 1500 miles? Or because fouled/ruined by the carb issue?


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## O52 (Jan 27, 2019)

Your plug gap is too wide. Need to bring it back to .035. 
Pertronix is not an HEI system but a points eliminator.


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## dan woodland (Jul 24, 2013)

I'll have to double check the gap, thx.


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## Lemans guy (Oct 14, 2014)

Runs ruff in gear at stop lights, stalls in reverse, black soot in tailpipe, runs better when you give it more gas.......

first I would do exactly what Blk judge recommends, fixing any carb problem won’t work if ignition and timing are off. Also agree with plug gap should be .35.

if no Vac leaks or other major ignition issue, what you are describing sounds like an overly rich idle circuit and or retarded timing. Probably both.

the car will idle on the idle circuit, idle holes and transfer slot and run on that up until 2500 RPM’s. This would also be when the car is in reverse.

also your idle timing may be insufficient and makes the car run rough. An idle timing of 20 to 26 say with 10 degrees from vacumn advance will give a nice smooth idle, and cool.

when you rev it up it does two things it adds centrifigal timing from the weights and springs, and about 2500 it adds in the main jets with a lot more air from the throttle plate....therefore it runs better.
Q
Nowvacumn leaks or bad or no, or clogged PCV system can mess up your mixture as well, so can flooding carb from a variety of ways.

ignition, get it right clean and tight,...then timing,...then carb mixture you will get it.

a cracked distributor cap can mess up your running as well.....stay with it!


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## PontiacJim (Dec 29, 2012)

Flooding. The car ran fine last year. It sat all winter. Float sticking, needle/seat not seating. Gaskets need to "swell" a little to seal better.

Check base carb nuts to make sure they are tight and not allowing air in.

If me, seeing it runs fine when you gas on it, hammer on the car a little with some good hard open runs, and burn up the gas in the tank and get fresh gas in it. These cars don't do well when they are not run and sit all winter even if you think you have tucked them away correctly. My brother has to go through this crap with his Mopar and 6-Pack each spring. He puts in stabil-360 and fills the tank. Carbs go south and he has flooding and then has to have a shop pull them apart and clean/rebuild. He finally had enough of it this year and is now pulling the carbs and installing an EFI 6-Pack set-up.

So my money is on the carb. Yes, .032"-.035" on the plug gap.


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## dan woodland (Jul 24, 2013)

Thanks for all the tips guys, much appreciated...

This is what I get when think of something and I post late at night without doing any research... I should have thought of some of these ideas. 

Didn't have time to do full timing check/adjustment today so I did an experiment (KISS). I realized the RPMs were down quite a bit from last season, timing light says 300-350 less so I bumped up the idle and she acted much like she used to last year. Sooo I'm assuming the timing is off (engine is now broken in) and I most likely have a carb issue (flooding/stuck etc).

I'm going to start from the beginning and go through each step I did after the rebuild 9plugs, timing, carb, idle etc etc). found my notes from the initial setup and testing... think I will go with one of my earliest timing settings 24 instead of 22 (where it should be now.).

Need to do family things on weekends so I'll get to this during the week..."my time" while everyone else is working... being retired is AWSOME!

Thanks for all the great ideas gents!


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## Mine'sa66 (Oct 30, 2019)

There's a million variables here that will be really hard to sort out but here's where I'd start...
Everything folks are mentioning about timing etc are all correct, but as I understand it, this ran fine when parked?
You didn't do anything to it? So the timing hasn't changed, the components probably didn't fail.
The carburetor did sit with fuel in it all winter long.
There's your problem. Winter here is 6 months long. I fix cars for a living. Every spring, we live this. Ethanolized gas is bad jujuj. You didn't mention what you used for a stabilizer, but there's a lot of types and in my experience there's a huge difference.
I used a product called Startron. It's an enzyme based product that removes the ethanol, while adding stabilizer to the gasoline.
Sounds like you have a rich condition and I'll bet you a cup-o-coffee that you have a float problem or a blocked air bleed.


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## dan woodland (Jul 24, 2013)

Mine'sa66 said:


> There's a million variables here that will be really hard to sort out but here's where I'd start...
> Everything folks are mentioning about timing etc are all correct, but as I understand it, this ran fine when parked?
> You didn't do anything to it? So the timing hasn't changed, the components probably didn't fail.
> The carburetor did sit with fuel in it all winter long.
> ...


Good point... more I think about it I agree. As I recollect I realized I noticed the "idle issue" late last year (October) when I put her in reverse. 

So if it's a float issue (new metal float installed 3 years ago during carb rebuild) and I set it dead-on as the instructions directed it sounds like the float isn't floating? If I take it apart I'm going to rebuild the whole thing again... wanted to get the 

Sta-bil 360 is the stabilizer I used. I also used an octane booster with 93 Octane fuel (I have had mixed opinions on the use of a booster).

What steps can I take to avoid the Bad JuJu in the future - beyond Startron which I see I can get at the corner store. I would prefer not to rebuild/repair the carb every few years. 

Thanks, Dan


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## PontiacJim (Dec 29, 2012)

Drive it. Fuel is going to evaporate just sitting in the garage. Can lead to things sticking/clogging as sediments or other things in the fuel fall out of suspension and create problems, accelerator pump drying out, and gaskets drying out and shrinking. The Stabil 360 in the gas tank does not prevent fuel from evaporating and drying out in the carb.

If you are not going to drive it, then you should start it up and let it run for 1/2 hour each week, turning the idle up to keep oil pressure up, get the engine hot, blow out any condensation in the exhaust, and keep fuel flowing through the carb and fuel lines.

Or, pull the carb each spring and go through it to ensure all things are in order.


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## Mine'sa66 (Oct 30, 2019)

dan woodland said:


> Good point... more I think about it I agree. As I recollect I realized I noticed the "idle issue" late last year (October) when I put her in reverse.
> 
> So if it's a float issue (new metal float installed 3 years ago during carb rebuild) and I set it dead-on as the instructions directed it sounds like the float isn't floating? If I take it apart I'm going to rebuild the whole thing again... wanted to get the
> 
> ...


Probably not that the float is no longer floating, but that you have crud (dried ethanol/gas residue) holding the needle open. Pretty easy to solve. But, less easy to solve and unfortunately more likely is that you have an air bleed that is plugged with the same stuff. Trickier as those passages are TINY and often not easy to find or clean. Also, running good fuel or fuel with solvents that will get rid of this stuff will not get to it as fuel doesn't run through there, air does. Sounds like you have the ability to tear into your carb yourself. You might be in there cleaning things up. As far as what to do? I have 8 cars on the road. The number of operators in my family has dwindled, so a lot of my cars sit. My GTO sits all winter. My plow truck gets driven very little in the summer. I run a heavy dose of Startron in anything that sits. Including generators, outboard motors, lawn tractor. I don't have to mess with my carbs. I'd say it works.
You're not talking e85 right? That's a whole different ballgame...


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## Mine'sa66 (Oct 30, 2019)

Mine'sa66 said:


> Probably not that the float is no longer floating, but that you have crud (dried ethanol/gas residue) holding the needle open. Pretty easy to solve. But, less easy to solve and unfortunately more likely is that you have an air bleed that is plugged with the same stuff. Trickier as those passages are TINY and often not easy to find or clean. Also, running good fuel or fuel with solvents that will get rid of this stuff will not get to it as fuel doesn't run through there, air does. Sounds like you have the ability to tear into your carb yourself. You might be in there cleaning things up. As far as what to do? I have 8 cars on the road. The number of operators in my family has dwindled, so a lot of my cars sit. My GTO sits all winter. My plow truck gets driven very little in the summer. I run a heavy dose of Startron in anything that sits. Including generators, outboard motors, lawn tractor. I don't have to mess with my carbs. I'd say it works.
> You're not talking e85 right? That's a whole different ballgame...


And what Jim says about driving it? Some of the best advice of all!


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## dan woodland (Jul 24, 2013)

Mine...

No NOT using E85... Regular High Test. Can't run it all year, I'm in Northeastern Ohio. 

I have to shut her down about the beginning of November. Love the Idea PontiacJim but I can't. First snow she is parked.

Yes, I've already rebuilt it once after finding a piece of cloth from a K&N filter in a jet. I'm pretty good at cleaning things so I know I can get it cleaned... I'll be looking for a rebuilt kit. Anyone have suggestions? Last time I used a Hygrade kit.

What is a heavy dose of Startron?

Oh and Jim I am using an accelerator pump made of material that is supposed to resist falling a part or deteriorating from fuel etc but I know how that goes. 

Thanks all!


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## PontiacJim (Dec 29, 2012)

Dan - "I have to shut her down about the beginning of November. Love the Idea PontiacJim but I can't. First snow she is parked. "

PJ - Lived in CT for 31 years. Are you telling me that it snows everyday in your neck of the woods? Plenty of good days when it doesn't snow and roads are clear of snow & ice. Cold doesn't hurt a car. 

Shutting your car down in November for 7 months is a choice, not a necessity.


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## O52 (Jan 27, 2019)

Buy your kit from Cliff Ruggles. Over the counter or NOS kits aren't as good as they used to be. The accelerator pump rubber isn't set set up for todays gas


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## dan woodland (Jul 24, 2013)

Jim,

Yes ultimately it is a choice, there are some good days here BUT the snow melter used here is *extremely* corrosive. Even after the roads are dry the melter stuck to metal parts sucks moisture out of the air so corrosion grows constantly. Even if you get the dry melter stuck in a tight spot it starts the corrosion process in a matter of days.

I've spent too much time, money and sweat to expose the car to that... even though I park her she is starting to show her age, I don't think the restore done 28 years ago was done very well. Driving her in our winters would only hasten the aging process. 

052,

Thanks for the info. I'm on his site now. 👍


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## 67ventwindow (Mar 3, 2020)

I live on a state highway in Missouri and everytime the weather man sayes snow they are spraying our road with at melting slime. My new cars undercarrage looks old already. I open the garage door and a window and run her my classics for a little bit and listen to the radio (detached garage), I dont know if I do it to keep the carb clean or just for the smells and hear the motor. Frankly I like working on the motors I clean out a carb on something every year. Tiller, weed eater, chainsaw, dirt bike, four wheeler, tractor, cars, and mowers. I think its why she keeps me around. That and mowing 4 acres every week.


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## dan woodland (Jul 24, 2013)

67ventwindow said:


> I live on a state highway in Missouri and everytime the weather man sayes snow they are spraying our road with at melting slime. My new cars undercarrage looks old already. I open the garage door and a window and run her my classics for a little bit and listen to the radio (detached garage), I dont know if I do it to keep the carb clean or just for the smells and hear the motor. Frankly I like working on the motors I clean out a carb on something every year. Tiller, weed eater, chainsaw, dirt bike, four wheeler, tractor, cars, and mowers. I think its why she keeps me around. That and mowing 4 acres every week.


lol After 34 years I hope mine keeps me around for something more than just chores. 

Exactly! That's what they use here as well! That stuff is nasty and you can't see it on the road all the time until it's too late!


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## Mine'sa66 (Oct 30, 2019)

dan woodland said:


> Mine...
> 
> No NOT using E85... Regular High Test. Can't run it all year, I'm in Northeastern Ohio.
> 
> ...


I live in Maine so I'm all about winter. There's no taking it on the street after the first snow in October until the roads have been washed off by spring rains in May. Just starting it will fill the bowls back up and hopefully keep the bleeds open. As I mentioned though, I do not start mine all winter long. Startron is one of several types of ethanol conditioners that use an enzyme to break down the ethanol. When I say "heavy" I mean double-triple the recommended "dose". It is safe to do so per the label.


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## dan woodland (Jul 24, 2013)

Mine'sa66 said:


> I live in Maine so I'm all about winter. There's no taking it on the street after the first snow in October until the roads have been washed off by spring rains in May. Just starting it will fill the bowls back up and hopefully keep the bleeds open. As I mentioned though, I do not start mine all winter long. Startron is one of several types of ethanol conditioners that use an enzyme to break down the ethanol. When I say "heavy" I mean double-triple the recommended "dose". It is safe to do so per the label.


Thanks for the details Mine'sa66. I do the same thing, I might be able to sneak out in April but it's usually May until I feel the roads are clean.


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## dan woodland (Jul 24, 2013)

Efforting to get in touch with Ruggles... hopefully tomorrow.


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## lust4speed (Jul 5, 2019)

Pertronix makes a complete HEI and if it is a "Pertronix HEI" as stated, the .045" gap is fine.


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## dan woodland (Jul 24, 2013)

Pertronix HEI I have came with a coil for on top of the cap and the electronics under the cap to replace the points system. It utilizes the stock distributor.


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## dan woodland (Jul 24, 2013)




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## lust4speed (Jul 5, 2019)

So it has an aftermarket module, but it was and still is an HEI distributor and the .045" sparkplug gap will work fine. Maybe drain the gas out and use it in your lawn mower or daily driver and get some fresh fuel in it.


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## dan woodland (Jul 24, 2013)

lust4speed said:


> So it has an aftermarket module, but it was and still is an HEI distributor and the .045" sparkplug gap will work fine. Maybe drain the gas out and use it in your lawn mower or daily driver and get some fresh fuel in it.


Thanks for the verification.


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## dan woodland (Jul 24, 2013)

Talked to Cliff Ruggles this AM. Nice guy, knows his s..t!!! Sent him pics of my setup, told me all about it and how to improve/correct several issues. Most of those issues he noted will make my car run perfectly!! Even offered to look at it in person(turns out he is only an hour or so from me - especially if I have any issues after I rebuild the carb utilizing his suggestions.


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## 1968gto421 (Mar 28, 2014)

Cliff is a great guy, always ready to help, glad he is close by for you take your GTO to. He really does know his s..t.


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## dan woodland (Jul 24, 2013)

Problem solved... mostly!! 

Before I rebuilt the carb I decided to implemented a couple fixed for issues Cliff saw in my pictures I sent him - figured I would change one thing at a time to see what helped with what and a rebuild at the same time as those other changes I wouldn't know what did the trick . 

Now she doesn't stink at idle, doesn't bang/lurch when put in gear (idle doesn't change at all), doesn't want to stall in gear (forward or reverse) and idles perfectly! Drivability has improved drastically, it actually brakes at lights now, it's not like I am holding back a raging bull at a stop light. And coasting is now coasting!! No more idle coasting at 30 miles per hour! 

I still have a stumble when hitting the throttle (bad accelerator pump) but I can live with that for now. I'll double check the idle timing tomorrow (no vacuum) and set the proper idle speed - Idle speed changed when I began using the correct vacuum source (one of Cliff's suggestions).

I also gave the transmission it's own vacuum source (Distributor and transmission were together). Now she shifts better (smoother).

I can still burn rubber, she flies on the highway and now is very nice to drive on the street.

Next, spark plug check, vacuum tune air/fuel mixture and a full carb rebuild (not necessarily in that order).

Thanks for all the input gents.


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## dan woodland (Jul 24, 2013)

Spoke too soon... ran better or a few trips then "fell off the table". Ran like crap after being hot and had to feather the throttle leaving the line. 

Took the carb apart today and cleaned it for a rebuild (as well as a spare carb - have an extra rebuilt kit). Waiting for the JB Weld to cure on the well plugs and reinstall tomorrow. Will redo everything next (timing, idle, high idle etc).


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## dan woodland (Jul 24, 2013)

A mechanic of 40+ years experience moved onto my street recently and offered to help me setup my car (carb, timing etc). At the moment I have 13 degrees initial timing and 42 total. She runs very good but found out my distributor vacuum advance is shot. He also showed me my choke pull off diaphragm was bad. I took the one from my backup carb as it tested good. 

He also offered to adjust the valves.

Amazing how many issues I had... goes to show you "don't know what you don't know"!!!


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## Lemans guy (Oct 14, 2014)

Turn that base timing back to 7 degrees...so you have 36 total until you can get that distributor right....too much timing will cause detonation..

vac advance should be hooked to full manifold vac to aid in your idle timing....


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## dan woodland (Jul 24, 2013)

Thanks Lemans Guy, those are not the final settings - I won't be driving it until everything is fixed. I will redo everything after valves are adjusted and vacuum advance is replaced.

I should have mentioned the 42 degrees was at 4K rpms (wasn't worried about final timing), just set it at 13 degrees base so I can start her and move her from my house to the mechanics to adjust the valves.


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## Lemans guy (Oct 14, 2014)

Super, that sounds much better. Lots of guys drive around with way too much advance timing, not unusual at all to see 35 degrees centrifigal timing and the base set at 12r 15!

and then a vac can that pulls 20 more degrees!... but you are doing it all the right way.

perseverance pays off!


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## dan woodland (Jul 24, 2013)

Also forgot to mention, if you are a Quadrajet owner and want to rebuild it or have it rebuilt by a pro look up Cliff Ruggles for the parts or service. The kit he sent me was dead on with what is needed for a full rebuild including secondary plate screws, power piston lock ring (with a slit built in) and secondary actuating cam. The former mechanic I'm working with said he wished he knew about Cliff Ruggles and his supplies years ago. "That was a nice kit" he said a number of times.

I'm like most of you, old school... do good work and I'll sing your praises, do bad work and I'll find another source... Cliff is my source. I bet he forgets more than I'll ever know about these cars and carbs.


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## dan woodland (Jul 24, 2013)

Well... Found broken rocker arm studs in engine while doing valve adjustments. Anyone know if the rocker studs go into any water passages? The mechanic I'm working with vaguely remembers they do but we want to conform before starting to disassemble the top of the engine. Also found the studs vary in length like the engine builder just used what ever he had laying around.

Also, anyone "know" these studs are grade 8? The one stud broke inside the lock nut! It's dirty like it's not a fresh break so we surmised it was broken at or shortly after the rebuild.

Thanks for any help in advance, Dan


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## Old Man Taylor (May 9, 2011)

The rocker arm studs are dry, they do not go into any water passages. There are a few of them that do on Edelbrock heads.


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## dan woodland (Jul 24, 2013)

Thanks Old Man Taylor... you are correct. Much appreciated.


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## dan woodland (Jul 24, 2013)

Weelllll....... finally got all the parts... studs arrived last week (grade 8 from Butler), but couldn't get poly locks from Butler (didn't trust the old lock nuts), they sighted supplier issues because of The Rona. Found poly locks at Summit...drove to pick them up after they put my order in limbo for a few days (apparently they have issues shipping because of The Rona)... installed studs and locks then found out I needed stud spacers (washers) because the poly locks bottomed out only when the allen lock screw was backed all the way out... back to Butler for some washers... washers arrived today and I installed them and set the valves. Put everything back together and she roared to life!!!! I'm sure the un-retired neighbors didn't appreciate a 10pm Pontiac 400 start up but I don't care!  

She sounded and ran great! no more tick and smoooooth! Tick is why I was doing the valve adjustments in the first place... plus it was the first adjustment since the rebuild some 1500-2000 miles ago.

Some time in the very near future I will set the timing (base and total) and let her rip!!!

Oh, almost for got... found some issues as well... while checking the total timing I noticed it "jumped" from x to y. Took out the rotor and noticed some grooves being warn in the "shelf" on the underside. Bought this rotor as part of a HEI kit from Summit. Turns out the under side is 1/8th inch thicker than other rotors (I.E. AC/Delco and Standard) which interferes with the weights travel as mechanical timing increases! 

Also found the HEI "brand sticker" had come off the module and was laying across the wiring connection (it's a foil sticker). That can't have been good either... so moral of the story, if you upgrade to HEI make sure the rotor you use has clearance for your weights at or near total timing and remove the sticker!

I also wonder if the new distributor weights are slightly thicker than OE. I will have to pull out the old weights and compare.


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## BearGFR (Aug 25, 2008)

Too late now, but ARP makes rocker studs in different lengths in case you ever want to get rid of the washers. FYI

Feels good to have some success, right? I'm glad it's coming around for you.

Good catch on the rotor. The 'joy' of aftermarket parts from different suppliers.

Something else to watch for: I'm running a Davis HEI on my 69. I discovered that it was possible for the weight pins and/or the holes in the weights themselves to wear enough so that there's some slop there -- enough that if you aren't careful, it's possible for the ends of the weights to get into an orientation where the ends overlap each other. If you then install the rotor and screw it down, it will clamp down on the weights so that they can't move even though the rotor is still sitting 'flat' like it's supposed to. They don't run too well with no mechanical advance and timing stays at your initial setting, no matter the RPM. It'll act just like a nasty carburetor problem - bucking, spitting, backfiring through the carb whenever you try to get heavily into the throttle. I got bit by that one - big time.

Bear


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## dan woodland (Jul 24, 2013)

You said it, feels good, really good! I can now do burn outs WITHOUT using the brakes!!!  And until I let off or run out of room!! 

So, thanks for the information... I did't want to make a long story out of it but I tried getting ARP bolts from Summit and they had none in stock. As I mentioned I can drive to one of their stores, so I ended up at Butler and you know the rest.

Ended up testing every thing under the hood... seems I have a vacuum leak in my headlight system (have a new headlight switch already) so I'll have to track that down and get a new check valve for my brake booster as well.

Thanks again Bear... a question, what should be my total timing when I start at 12 base? because of the rotor issue I was at 42, now I'm at 49 at approximately 2650rpms. That seems high.

As far as engine with exception of roller lifters and a slight larger cam than stock it's as close to stock as you can get.

Thanks in advance, Dan


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## BearGFR (Aug 25, 2008)

Yeah, 49 seems pretty high to me. The best way to optimize timing for your car involves taking it to the track, making runs under "as close as you can get them" identical conditions, making small changes until you find what nets the best E.T.'s 

Which heads are you running?

Something in the neighborhood of 35 total (no vacuum, 2500 rpm) is in the ballpark for "most" open chamber heads. I don't remember... which distributor are you running?
Factory points distributors and HEI's have a pin that limits the amount of advance travel. You can reduce the amount of travel and thus how much mechanical advance they add by putting a bushing over that pin --if you need to-- like if (for example) the engine likes 35 total but doesn't want to idle well at the initial setting that gives you that. In the "old days" , aftermarket advances recurve kits with different weights and springs usually also included a bushing for that purpose. 

Bear


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## dan woodland (Jul 24, 2013)

62 heads... not sure on the distributor. On the bushing you mean where the weight pivots? See pic. I'm fairly certain those are the weights that came with the car. The springs are new, I'd have to look up the paper for the stiffness.


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## BearGFR (Aug 25, 2008)

You have to pull the distributor, remove the gear, and remove the shaft to get enough access to the pin (if it has one) to be able to stick a bushing on it. It'll be on the center "T shaped" ears that the springs clip to and will stick 'down' through a slot in the larger plate - the one that moves. The pin will be on the 'back side' of one of the pins that the springs clip to. You might be able to see it, if it's there, with a mirror so you can see the underside of the center plate - the 'other end' of one of the spring pins or maybe feel for it with a thin feeler gauge blade. I'm having a faded memory (I'm olde) that some HEI's don't have that limiting pin. Instead the advance limit is controlled by how the 'tails' of the advance weights meet each other. It that's the case, then the amount of travel can be tuned by carefully bending the small tails of the weights so that the springs can't pull them "together" as much. Some HEI advance kits may have weights with different shapes - not sure about that. 

Here's links to photos of what the pin (with a bushing installed) looks like on the factory points distributor.
Points distributor advance limit with bushing
Alternate view

Not all HEI's are the same. Looks like some may use limit pins that are accessible from the top side.
HEI with limit pins
Your photo kinda looks like yours might be like that.

Anyway, hopefully this helps. The idea is to limit the amount of mechanical advance movement that's in the distributor so that you can get both a TOTAL and an INITIAL setting that makes your engine happy. The total value being the more important of the two, because that's where the power is.

Bear


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## dan woodland (Jul 24, 2013)

BearGFR said:


> You have to pull the distributor, remove the gear, and remove the shaft to get enough access to the pin (if it has one) to be able to stick a bushing on it. It'll be on the center "T shaped" ears that the springs clip to and will stick 'down' through a slot in the larger plate - the one that moves. The pin will be on the 'back side' of one of the pins that the springs clip to. You might be able to see it, if it's there, with a mirror so you can see the underside of the center plate - the 'other end' of one of the spring pins or maybe feel for it with a thin feeler gauge blade. I'm having a faded memory (I'm olde) that some HEI's don't have that limiting pin. Instead the advance limit is controlled by how the 'tails' of the advance weights meet each other. It that's the case, then the amount of travel can be tuned by carefully bending the small tails of the weights so that the springs can't pull them "together" as much. Some HEI advance kits may have weights with different shapes - not sure about that.
> 
> Here's links to photos of what the pin (with a bushing installed) looks like on the factory points distributor.
> Points distributor advance limit with bushing
> ...


Perfect! 

Thanks Bear! Looks like I do indeed have an HEI with bushing adjustment under the cap. I'll let you know.

Much appreciated! 

Always something to learn with these cars!! This latest adventure has made this a hole new car!


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## Lemans guy (Oct 14, 2014)

Dan, you won’t have bushing on that dist you will need a curve kit for GM HEI, the new weights change the configuration of the centrifugal advance limits and lighter springs will help.

ditch that vacuum can also, see that number on it it is giving you 20 degrees of timing advance, way too much on today’s gas....

Hook your new vac advance to full manifold vacuum, to get a cool and steady idle.

The vacumn can you want is Standard Motor Parts SMP VC 302,....O’Reilly calls it a BWD V482.....Napa calls it a VC 1703.....Rock Auto calls it VC 302.....

all are made by standard.

a good curve kit is Moroso #72300 for GM HEI ,,, Mr. Gasket, Crane also make them.

do not buy the Moroso #72310....it is for points distributors.

You got way too much timing at 49, and your vacumn is adding 20....

that vac can I gave you will pull 8 to 12 degrees timing at the crank...usuallly pulls 10.

good luck let us know how you do


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## dan woodland (Jul 24, 2013)

OK, so I understand... 

I know the springs control how fast the mechanical timing comes in… Also understand ported versus manifold vacuum.

If I want to get a total timing advance of 32-35 (engine builder said it should like that) I can reach that by using vacuum advance and mechanical methods. 

I.E. If I use Ported Vacuum I set the base timing at 12 degrees (idle timing), Vacuum kicks in at a predetermined RPM (current vacuum canister is a 20 degree advance can) so I get 22 degrees then at a predetermined RPM the vacuum drops off and the weights are supposed to take over. Weights are currently setting my advance to 49 degrees which is too high - adding 27 to the vacuum advance. This means I am adding 27 degrees mechanical and the weights are traveling too far out (hitting my old rotor) for what I need - obviously since I’m at 49 degrees in the current setup.

So, if I get the 8-12 degree vacuum can which usually pulls 10 degrees advance and use manifold vacuum which gives me vacuum full time I set my base timing at 12 degrees and the vacuum can pulls 10 more for 22 total… 

How many degrees will I get form the new weights suggested?

Thanks for your help!!


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## Lemans guy (Oct 14, 2014)

Let’s restart. You want total timing to be 36 BTDC. Total timing does not include vacuum timing. Total timing is not tied to any RPM’s.

It is the total amount that your timing can advance at WOT. When no vacuum is present. Total timing is a combination of base timing, set with your hand and timing light, and the centrifugal timing advance by the weights. Springs don’t matter here.

it is how far the weights will advance, and then stop by hitting their hard metal stop.

base timing and centrifugal timing must be matched to achieve 36 degrees. So if your centrifugal total is 24 degrees you set base timing at 12 degrees =36. If centrifugal 26 set base at 10 = 36.

Now vacuum timing, Vacumn timing is a great benefit to make your car run cooler smoother and better accelerate. It adds the necessary advance above total timing, 10 degrees is perfect, for all that benefit.

the reason you need it is at idle and cruise the mixture is leaner and needs spark much earlier to get a complete burn.

use the vac can I told you hooked to full manifold vac.

Now the springs and how everyone talks this advance shorthand wrong. ”I got 36 degrees at 2500 RPM” they say. So I am good. If that is your total timing you are good, but if your timing advances beyond that to 49 degrees at 4000 Rpm.. you are not good.... as you are not reading total timing just springs at various times.

once your total timing is established, then you can adjust when it comes in at what RPM with springs. You want to bring it all in near 3000 or so 32 3400 even for good running.....

springs are meaningless until all other parameters established.

Base Timing is set by hand and locked down. Centrifugal timing is Weights and springs and Operates on RPM’s only.

Vacumn timing is tied to your gas pedal...light load, more timing, pedal down WOT no Vacumn timing.

you will get it, think about the 3 methods of timing at play...base, Centrifigal and Vacumn.

sync em all up and it will run great!


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## Lemans guy (Oct 14, 2014)

PS curve kit weights vary....as do wear on distributors....anything mid 20’s is good.

that will put your base at 8 to 12 or so.

then when you add the 10 from the vac can your idle timing ...base + Vacumn will be 20, 22 or so. It will idle real smooth and cool there.


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## BearGFR (Aug 25, 2008)

Amen - get it out of your head that vacuum has anything to do with the 32-35 total you're shooting for. It doesn't. Vacuum advance is there only for 'extra' advance during part throttle, light load conditions. It helps with engine cooling and fuel economy under those conditions. Power during heavy load / wide open throttle comes from the combination of initial timing and how ever much mechanical advance the system is adding at a particular rpm. Under heavy load, the engine doesn't make enough vacuum to activate the vacuum canister at all. 

The Davis HEI my 69 is capable of a range from 0 to 20 degrees mechanical depending on rpm, so to get 35 total requires 15 initial. With my head's (72 cc round port Edelbrocks) my engine seems happy. 

Bear


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## Lemans guy (Oct 14, 2014)

Exactly Bear, and sometimes I curve em at 18 base and 18 centrifugal and add 10 degrees vac. For the real radical roller cam that will give 28 degrees advance at idle...

18 base + 10 vacumn....the overlap reversion really leans those mixtures so some engines take it. But most ....18 to 28 centrifugal advance....


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## BearGFR (Aug 25, 2008)

Lemans guy said:


> Exactly Bear, and sometimes I curve em at 18 base and 18 centrifugal and add 10 degrees vac. For the real radical roller cam that will give 28 degrees advance at idle...
> 
> 18 base + 10 vacumn....the overlap reversion really leans those mixtures so some engines take it. But most ....18 to 28 centrifugal advance....


Hmmm.... that gives me an idea. At idle RPM with my new cam, it's definitely on the "knee of the curve" as far as manifold vacuum goes. As little as 50 RPM makes a big difference in vacuum which makes it really tough to get a good idle mixture, especially when the a/c compressor and/or the electric fans kick in, so much so that the idle mixture goes super lean when either of those things happen. I might try more initial lead to see if that helps make it less sensitive. Just before I pulled it to get into the current re-do, I tried some smaller idle air bleeds which seemed to help some. This might help too.

This cam is a solid roller - 251/257 @ 0.050, 110 LSA, .620 net lift at the valves with 1.5:1 rockers. From Bullet, I'm told it's got the tallest lobes (0.4300 lobe lift) that can physically be installed in stock dimension cam bearings.

Thanks for the idea.

Bear


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## Lemans guy (Oct 14, 2014)

Yes you can likely take some more idle timing...don’t be afrai of 28 even 30 as long as you can take it out of the centrifugal...

agree on idle air bleeds, I use a QFT carb and can curve the idle circuit, and all the circuits easy.....


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## Lemans guy (Oct 14, 2014)

You could try 38 total , without any major changes, just dial up you base 3 more to 18...you have 29 centrifigal...that is 38....

some of these big Pontiac engine take that..

but you have to then test drive it and make sure that you don’t get pinging/detonation..

if you don’t it may help that lean idle mixture


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## Lemans guy (Oct 14, 2014)

I meant 20 centrifugal is what you have not 29


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## Lemans guy (Oct 14, 2014)

I know Davis is a great outfit first class on their stuff. But I don’t like those adjustable vac cans that I one I use a lot on HEI’s pulls that timing in at very low Vacumn and only gives 10 degrees ...perfect.


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## Lemans guy (Oct 14, 2014)

What is your idle timing Bear?...15 + how much from vacumn can?


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## BearGFR (Aug 25, 2008)

I set idle timing with it disconnected and have never looked at what the can adds.


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## Lemans guy (Oct 14, 2014)

Check it, it tells you what it really is. That is also the timing when you set your carb idle circuit. So that is where it runs.


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## dan woodland (Jul 24, 2013)

Lemans guy said:


> Let’s restart. You want total timing to be 36 BTDC. Total timing does not include vacuum timing. Total timing is not tied to any RPM’s.
> 
> It is the total amount that your timing can advance at WOT. When no vacuum is present. Total timing is a combination of base timing, set with your hand and timing light, and the centrifugal timing advance by the weights. Springs don’t matter here.
> 
> ...


OK, that makes sense now. Thanks for the clarification - not the relationship between the advance types. Thank you very much!

Weights will be here Saturday, vacuum can Sunday and vacuum tubing tomorrow. Found another leak today!! I'm replacing every vacuum line I can.

I will let you know how it goes.

Thanks again! Dan


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## Lemans guy (Oct 14, 2014)

Try one light and one medium springbform the curve kit,...usually gets you close


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## BearGFR (Aug 25, 2008)

Lemans guy said:


> Check it, it tells you what it really is. That is also the timing when you set your carb idle circuit. So that is where it runs.


 I'll probably eventually get to it, once I get it back together. Right now I'm hearing that there's an 8 week lead time on a set of pistons though so it's not going to be soon.


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## Lemans guy (Oct 14, 2014)

Yeah everything has slowed down, you will get er done eventually...sounds like it will be a great one.


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## Montreux (Mar 8, 2009)

dan woodland said:


> OK, so I understand...
> 
> I know the springs control how fast the mechanical timing comes in… Also understand ported versus manifold vacuum.
> 
> ...


Timing is set with the vacuum advance disconnected and plugged. "Total" timing is initial plus centrifugal, and should be in the 32-36 range. The RPM must be high enough that the centrifugal advance is "all in". With stock springs, this may be as high as 4000 RPM. Lighter springs bring the advance in sooner; it may be all in as low as 2000 RPM. Rev the engine while watching the timing; when it quits changing, you're there!

Vacuum advance provides additional advance at part throttle (cruise). At full throttle, vacuum goes away, and vacuum advance goes away. If your car runs smoothly at full throttle, but rattles (detonates) at part throttle, you have too much vacuum advance. Less than stock vacuum advance is probably a good thing with today's gas.

So 40-50 degrees advance with vacuum advance connected is not a problem.


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## dan woodland (Jul 24, 2013)

Montreux said:


> Timing is set with the vacuum advance disconnected and plugged. "Total" timing is initial plus centrifugal, and should be in the 32-36 range. The RPM must be high enough that the centrifugal advance is "all in". With stock springs, this may be as high as 4000 RPM. Lighter springs bring the advance in sooner; it may be all in as low as 2000 RPM. Rev the engine while watching the timing; when it quits changing, you're there!
> 
> Vacuum advance provides additional advance at part throttle (cruise). At full throttle, vacuum goes away, and vacuum advance goes away. If your car runs smoothly at full throttle, but rattles (detonates) at part throttle, you have too much vacuum advance. Less than stock vacuum advance is probably a good thing with today's gas.
> 
> So 40-50 degrees advance with vacuum advance connected is not a problem.


Thanks for the info Montreux. Much appreciated!


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## dan woodland (Jul 24, 2013)

Car is running like a scalded cat!!! Long story short there were several issues masking each other... Timing is at 12 initial, 22 with vacuum and 30 total... used new weights, new vacuum can and two different springs, all as suggested earlier.

I'll detail the all the issues on my main thread...

It's almost not fair to my B.F. Goodrich tires... I can burn rubber without a brake stand and keep it going as long as I can (I have an automatic) until she shifts into high gear...

Thanks for all your help!!!

Dan


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## Lemans guy (Oct 14, 2014)

I would turn that base timing up 4 to 6 more degrees......giving you 16 or 18 base and 26 or 28 at idle.....with total timing then at 34 or 36.....it will run even better...

just make sure that your total numbers are accurate and you get no pinging.......


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## dan woodland (Jul 24, 2013)

Thanks for the information Lemans Guy... I'll try to make the change my riding season ending very soon and fall/winter hobbies are poised to fill the slot. 

Question: If it pings is it only timing related or fuel etc??? If timing just back out the timing? I've had "three" pings in the past and it goes away as I accelerated "through it". I assume you mean pinging all the time under heavy load.

Thanks again and in advance, Dan


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## Lemans guy (Oct 14, 2014)

Dan, yes pinging is the sounds detonation makes in the cylinder when the fuel/air mixture fires oof at the wrong time. Here we are talking about too early as you advance the timing.

it is basically the piston wobbling in the cylinder and the mixture fuel air explosion “ringing the bell” of the metal engine. When timing is set right the spark ignites at the right millisecond and powers the piston down without a wobble and without an inefficient power stroke.

so folks say what is perfect timing on our 60’s V8’s.......optimal for most power and efficiency and cooling......is two degrees below detonation!.....that is the most for power and efficiency and smooth running.

so I set distributors to start with at 36 total timing.....and go from there. Most engines take it, but if any pinging retard the base timing 2 degrees and recheck. If still there retard two more degrees and recheck, until the pinging is eliminated.

Now some Pontiac can even take 38 or 40 but be careful as that could cause detonation. Some guys like 34 degrees to start. But if you set it at 36 for street performance and no pinging that is agood place to be with your numbers.

also as that total comes in it can ping as you accelerate. This happens when there is too much advance as you sweep up the power. It happens from too aggressive a spark curve, trying to get it all in real low and or a vac can with too much timing in it. Many I see have 20 or 25 in a vac can way too much.

your number sound ok just be sure of the goal and just dial it up a bit, and test. I don’t recall when you said your total was all in but 3000 or 3200 is good, you don’t have to have 2500..

that is real aggressive and will mean light spring and sometimes centrifugal advance coming in on top of your idle timing. You don’t want that.


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## dan woodland (Jul 24, 2013)

Great info thanks LG! That helps a ton.

I may have to change out the weight springs - I think the timing may be advancing too fast (I remember all-in at 2,750 so I'll have to double check). I used one light and one medium as you suggested previously.

Hopefully I can bump increase the timing a bit and test it but they are calling for temps in the 30s here this week. 

I also have to wait until my vacuum system repair parts arrive - hose, check valves, etc... Should be here in the next few days. I need to fix the vacuum so I don't chase the timing setting - like I did before I fixed what I've done so far. I suspect I am still getting erroneous or inconsistent timing values because of the leaks - for example, after a long run the engine idle changes (rises) between warm up and return (about 2 hrs later). I want to fix all vacuum issues so I can set the timing with no "outside" influences.

Thanks again.


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## dan woodland (Jul 24, 2013)

P.S. Guy that helped me set timing says total timing came in at 2700.


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## Lemans guy (Oct 14, 2014)

You can leave it at 2700,......just drive and make sure it does not ping.......Younare looking for somewhere between 2500 to 3500...with no pinging....lower is more aggressive but ok as long as no pinging and it does not bring centrifugal in on top of idle...

in other words it ends at 2700 but when does it start,..this is centrifugal advance....so something to look for


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## dan woodland (Jul 24, 2013)

Got it, thx!!! your help is great appreciated!

Dan


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## Old Man Taylor (May 9, 2011)

2700 is very quick with today's gas. It's great if it doesn't ping, otherwise change the lighter springs on the advance weights for heavier ones.


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## dan woodland (Jul 24, 2013)

Thanks OMT, much appreciated! I have to find the box/specs to see what springs bring it in later so I know what I have. Between family stuff and such I have a short memory when it comes to the car stuff. 

If it runs as good as it does now I can't wait to make it run even better!! Hope winter holds off a few more weeks. 

Dan


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## dan woodland (Jul 24, 2013)

Found it...

RPM 500 1000 1500 2000 *2500 3000* 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 
Spring 
LIGHT (Copper) 0º 10º 20º 22.5º *23º 23º * 23º 23º 23º 23º 23º 23º 23º 23º 23º 23º 
MEDIUM (Silver) 0º 0º 6º 13º *19º 23º* 23º 23º 23º 23º 23º 23º 23º 23º 23º 23º 
HEAVY (Gray) 0º 0º 0º 6º *10º 16º* 21º 23º 23º 23º 23º 23º 23º 23º 23º 23º 

I'm in the middle of the highlighted zone...

I'm using one LIGHT and one MEDIUM spring hence being between 2500 and 3K.


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## Lemans guy (Oct 14, 2014)

Right a good place to start, it gets you close but you need to make sure it does not ping and you also need to verify it with a timing light. Then you will know what it actually is 

those springs vary a lot, the chart is not a super accurate measure.


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## dan woodland (Jul 24, 2013)

Good point, thanks for everything LG.

Dan


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