Strange engine issue
Thread Starter
Pro
Joined: Apr 2006
Posts: 647
Likes: 22
From: Norwalk CT and Boynton Beach FL
Strange engine issue
I have a 1975 L82 all stock. The engine has 78,000 miles on her and the top end was rebuilt about 4,000 miles ago. By that I mean valve job, valve springs, lifters, cam and timing chain. Recently, sometimes when I start the car, the engine barely turns over --- like the timing is too advanced and the pistons are firing too early. Other times it starts up just fine. Once the engine is running, the engine runs fine with no pings. I retarded the timing a bit --- start-up issue still happens sometime. I retarded it a bit more --- still happens. I looked in the distribution and everything looks tight. I replaced all of the internals in the distributor (the chip, rotor, etc.) --- still no solution. Anybody have any ideas where to look next???? Thanks
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
I'd start checking the ground cables- both the one from the battery to the frame and then the one from the frame to the block. Next would be the positive cable- end to end resistance. And be looking at the insulation on all of those cables for cracks. Moisture gets into a cable, it corrodes internally and the resistance goes up.
Melting Slicks
Joined: Feb 2006
Posts: 3,105
Likes: 96
From: Sunrise FL
Melting Slicks
Joined: May 2002
Posts: 2,431
Likes: 52
From: Florida
Camshaft walk?
Excessive distributor gear end play?
Loose starter bolts?
Missing starter rear support bracket?
Loose starter wiring?
Starter bushings?
Bad grounds?
Battery failing, cell going bad?
Excessive distributor gear end play?
Loose starter bolts?
Missing starter rear support bracket?
Loose starter wiring?
Starter bushings?
Bad grounds?
Battery failing, cell going bad?
Thread Starter
Pro
Joined: Apr 2006
Posts: 647
Likes: 22
From: Norwalk CT and Boynton Beach FL
All very good suggestions. I will start with the battery (not that old), cables and grounds. Cam, Timing chain, distributor and starter are relatively new (less than 5000 miles). I think the issue does not happen on cold starts, but after warm-up, but I usually have a trickle charger on the battery so cold starts should have a fully charged battery. I have one of those kill switches on the battery and that will be the first place I look.
I'll keep you all posted and THANKS for all your suggestions
I'll keep you all posted and THANKS for all your suggestions
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Drifting
Joined: Jul 2011
Posts: 1,697
Likes: 139
From: Syracuse NY
Yeah, buy why NOW, just after the top end rebuild? (Im a firm believer of heat soak, some guys on the forum laugh it off as a million other problems...but again I ask, why is it just NOW happening?)
Start with a 30 dollar starter blanket. If that works, you know the culprit.
Start with a 30 dollar starter blanket. If that works, you know the culprit.
Race Director
Joined: Oct 2008
Posts: 19,147
Likes: 1,667
From: Long Island
Yeah, buy why NOW, just after the top end rebuild? (Im a firm believer of heat soak, some guys on the forum laugh it off as a million other problems...but again I ask, why is it just NOW happening?)
Start with a 30 dollar starter blanket. If that works, you know the culprit.
Start with a 30 dollar starter blanket. If that works, you know the culprit.
Many parts were replaced, therefore the carb was off the engine , could have been dropped and upset the floats etc. Bet with all the new parts the idle and mixture was reset.
I would run the engine with break in lube added and see if there are any tight spots. Since he did not have the problem before the RE-build something is different.
When you build racing engines you learn "fast" that each time heads or manifolds are removed the block reacts to the new stress of the new correctly torqued bolts and all things change.
I would add an insulator under the carb and run some break in lube added to the oil for a hundred miles or so and see if the trouble goes away. The break in lube won't hurt a thing so it's a harmless check.
just some thoughts.. from old school thinking.
Thread Starter
Pro
Joined: Apr 2006
Posts: 647
Likes: 22
From: Norwalk CT and Boynton Beach FL
I removed the battery kill switch, which never seemed to work properly, and the issue seems to have gone away. Not driving the car much in the winter, but all seems OK now.
Thank you ALL for your input.
Wishing you all a Happy New Year!
Thank you ALL for your input.
Wishing you all a Happy New Year!
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
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