Cylinder compression for inactive L82
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Joined: Mar 2018
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From: Watertown NY
Cylinder compression for inactive L82
I purchased a 1974 L82 that was restored cosmetically but not mechanically. It sat for 5-6 years and only started occasionally.
Supposedly the engine was rebuilt in 1990 and has only 20,000 miles on it. Each cylinders compression measured 140 lbs.
Leakdown was around 10 lbs. Does this sound good. With some tuning and adjustments it pulled 220 hp on a chassis dyno.
thanks Tom
Supposedly the engine was rebuilt in 1990 and has only 20,000 miles on it. Each cylinders compression measured 140 lbs.
Leakdown was around 10 lbs. Does this sound good. With some tuning and adjustments it pulled 220 hp on a chassis dyno.
thanks Tom
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Leak down testing is given as a percentage. 10% is a pretty worn out motor. Was it rings or the valves leaking.
New quality rebuilds are less than 3%
New quality rebuilds are less than 3%
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
This was last year on my 396 stroker motor. leak down was perfect , actually amazing for an older motor. But I had visible blue smoke from the valve guides leaking oil around the stems under high vacuum. Like between gear shifts.
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Joined: Mar 2018
Posts: 97
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From: Watertown NY
Stopped by the shop yesterday. I guess the leak down was less than 10%. Ok but not great. We did install the FITech EFI system. Motor runs great. Very smooth. We will do another dyno run to tune with the new system. Next year I’ll redo the motor as it’s tired. Ok for now but thinking higher compression pistons and aluminum head.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
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From: Unreconstructed, South Carolina
Stopped by the shop yesterday. I guess the leak down was less than 10%. Ok but not great. We did install the FITech EFI system. Motor runs great. Very smooth. We will do another dyno run to tune with the new system. Next year I’ll redo the motor as it’s tired. Ok for now but thinking higher compression pistons and aluminum head.
... there are better cam profiles as well ... choose a piston with a thinner ringpak.
Burning Brakes
Joined: Jan 2003
Posts: 961
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From: Frederick MD
Stopped by the shop yesterday. I guess the leak down was less than 10%. Ok but not great. We did install the FITech EFI system. Motor runs great. Very smooth. We will do another dyno run to tune with the new system. Next year I’ll redo the motor as it’s tired. Ok for now but thinking higher compression pistons and aluminum head.
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Team Owner
Joined: Apr 1999
Posts: 21,953
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified