3.4 crate engine compression test

[MGAJIM]

Does anyone know the spec for the normal cylinder compression value? I understand "even" betwen cylinders is good, but at what pressure? Thanks.

[gectek]

if you are doing a test, even in the books they will tell u higher than 100psi is the rule of thumb, but my 3400 ga gave me 130 on almost all cylinders and that was with 160k miles on it, not too bad. i think they are supposed to be within 20% from highest to lowest or something like that

[geoffinbc]

Yea 120 or more is good. But you wont get an accurate test on a dry crate motor anyway. It needs to be broken in first. The rings wont seal right until they are seated correctly after break in.

[lowflyer]

Compression readings

There can be some differences between gauges, but my 3.4 crate engine recorded 180-185# across the board with 1200 miles on it.

One thought, make sure that your throttle body/carb is open when doing the compression check. If it can't breath it will be low.

[gectek]

well if they arent sealing right you can do a wet test, kinda messy and time comsuming, but it gets the rings to seal