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Joined: Nov 2022
Posts: 51 Likes: 2
Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Nov 2022
Posts: 51 Likes: 2 |
54-235 compression test
1- 78
2- 90
3- 90
4- 90
5- 90
6- 90
What do you guys think?
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Joined: Nov 2001
Posts: 19,758 Likes: 63
ChatMaster - 15,000
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ChatMaster - 15,000
Joined: Nov 2001
Posts: 19,758 Likes: 63 |
2 -6 are good. They are within the +/- 5 psi desired. I would first check the adjustment on the number 1 valves and also check to see if there is any indication of a sticky valve. If that is okay there is probably a leaky valve. If it were mine I would drive it to see if it gets worse or better. If the engine has not been run much lately there could be a thin layer of rust that might be at least part of the problem and with running might get better. Not likely but worth a try.
How Sweet the roar of a Chevy four!
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Joined: Jan 2002
Posts: 30,701 Likes: 141
ChatMaster - 25,000
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ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,701 Likes: 141 |
The compession for that engine should be at least 120 to 130 p0unds. Try a different gauge. I would run some ATF through the carb throat at a fast idle and see if that helps sickey rings or valves.
Gene Schneider
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Joined: Dec 2007
Posts: 4,024 Likes: 99
ChatMaster - 4,000
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ChatMaster - 4,000
Joined: Dec 2007
Posts: 4,024 Likes: 99 |
Squirt oil into the cylinders and run the compression test again. If the compression goes up significantly that will indicate poor sealing of the rings.
Rusty
VCCA #44680
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Joined: Nov 2022
Posts: 51 Likes: 2
Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Nov 2022
Posts: 51 Likes: 2 |
Okay I check compression with the vacuum advance disconnected and got some different results.
1-100
2-105
3-103
4-98
5-100
6-95
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Joined: Jan 2002
Posts: 30,701 Likes: 141
ChatMaster - 25,000
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ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,701 Likes: 141 |
Disconnecting the Vac. advance has nothig to do with the compression. Opening the throttle is the only thing mentioned in the SHOP MANUAL.
Disconnecting the Vac. advance will omly cause a vacuum leak.
Diffeernt engine temps. and cranking speeds can cause it to vary along with squirting oil into the cylinders.
Last edited by Chev Nut; 08/31/23 01:37 PM.
Gene Schneider
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