Lost Compression
Thread Starter
Member
Joined: 10-15-2020
Posts: 55
From: Oklahoma
I used a long screw driver in number 1 and the check the timing mark on the cover. It wad off about 1/4 of an inch. I marked the chain at the intake next to the head and the lined up the pulley to the cover. The chain moved about 1 chain link. That would be close enough to start anyway.
That shouldn't be far enough off to cause this kind of competition drop. With no visible contact marks on the pistons and equally low competition across the engine what else would cause this?
I'll hook air to number 1 to see if the valves aren't sealing as you suggested. I'll let you know.
That shouldn't be far enough off to cause this kind of competition drop. With no visible contact marks on the pistons and equally low competition across the engine what else would cause this?
I'll hook air to number 1 to see if the valves aren't sealing as you suggested. I'll let you know.
Thread Starter
Member
Joined: 10-15-2020
Posts: 55
From: Oklahoma
No, the lifters were out of the old motor. It ran ok except for the blown head gasket between 3 and 4. The head was off since January. I only swapped them because of the rust on the cams and lifters in this motor.
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Joined: 10-13-2011
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From: Welland,Ont Canada
Thread Starter
Member
Joined: 10-15-2020
Posts: 55
From: Oklahoma
Let me clarify. The rollers on the rocker arms were rusted, so swapped assemblies from old motor. What I saw in the attached link, I followed the procedure described. Is it possible for the lifters to go flat from sitting a few months? Both engines had good compression when checked. The original motor just ran ruff. How do check the lifters?
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Joined: 12-06-2009
Posts: 11,721
From: Alabama
The lifters would all have to be holding the valves open for you to lose compression on all cylinders.
I would say that lifters are not the problem.
For everything to be so rusted inside the engine, then a lot of moisture must have gotten inside. I would be worried about the cylinder walls having that rust also.
I would say that lifters are not the problem.
For everything to be so rusted inside the engine, then a lot of moisture must have gotten inside. I would be worried about the cylinder walls having that rust also.
Thread Starter
Member
Joined: 10-15-2020
Posts: 55
From: Oklahoma
I put air to the cylinders and the only place I heard air was the crank case. I think firemangeorge was right. I just don't understand how this engine could have good compression two months ago and 20 to 30 pounds now. It been stored inside on an engine stand. I had some strange results from more compression testing. Cylinders 1 and 4 had compression on some tests and not on others. I dis a wet test but the compression didn't improve. I can't see the cylinder walls with my bore scope the camera is too long and can't bend enough to see anything but the center of the pistons. I am soaking is down with PB Blaster to free up the rings. As far as the valves go I couldn't hear anything at the intake or the exhaust with my stethoscope. I will keep working on the rings for now.
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Joined: 03-29-2022
Posts: 1,241
From: Davison MI
I put air to the cylinders and the only place I heard air was the crank case. I think firemangeorge was right. I just don't understand how this engine could have good compression two months ago and 20 to 30 pounds now. It been stored inside on an engine stand. I had some strange results from more compression testing. Cylinders 1 and 4 had compression on some tests and not on others. I dis a wet test but the compression didn't improve. I can't see the cylinder walls with my bore scope the camera is too long and can't bend enough to see anything but the center of the pistons. I am soaking is down with PB Blaster to free up the rings. As far as the valves go I couldn't hear anything at the intake or the exhaust with my stethoscope. I will keep working on the rings for now.