compression testing questions
Thread Starter
Launching!
Joined: Jul 2004
Posts: 249
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From: Florence, MS
compression testing questions gonna do a compression test on my car one day next week while im doing header and spark plug/wire install. should it read a certain number on the guage or just be close across the board. im just doing all the troubleshooting i know to do to try n get this thing running right. i read somewhere that its more accurate if you squirt a lil oil in the cylinder is that true? also read that you need to get the engine to operating temps is that true? i sure hope not cause its a pain getting spark plugs in and out as it is.
IIRC a stock LT1 should show compression around ~180+ and be within 10% of each cylinder. And the motor should definitely be warm.
A little bit of oil in the cylinder helps to keep the rings temporarily sealed, but is only really used to determine a bad valve if you have low compression in one cylinder.
A little bit of oil in the cylinder helps to keep the rings temporarily sealed, but is only really used to determine a bad valve if you have low compression in one cylinder.
Thread Starter
Launching!
Joined: Jul 2004
Posts: 249
Likes: 0
From: Florence, MS
Now how am I gonna get the plugs out with the motor warm lol. Them headers will be on fire . Not to mention by the time I get all the plugs out it will be cool again lol. I did one cylinder the other day Just trying out the tester n it was nowhere near 170
Did you keep the TB blades open?
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Verdad Gallardo Thread Starter
Launching!
Joined: Jul 2004
Posts: 249
Likes: 0
From: Florence, MS
not possible the intake and the fuel injectors are off. had to replace intake gaskets and fpr trying to track a fueling problem which the fpr was leaking so that might have been it but im gonna do a noid light test too and then spray patter check. so the fuel cant get in there but was wondering if it would be impossible to check compression with the intake off. thanks for letting me know tho
not possible the intake and the fuel injectors are off. had to replace intake gaskets and fpr trying to track a fueling problem which the fpr was leaking so that might have been it but im gonna do a noid light test too and then spray patter check. so the fuel cant get in there but was wondering if it would be impossible to check compression with the intake off. thanks for letting me know tho
It's absolutely fine to check compression w/ the intake off.
