Hey all,
Im trying to find the compression numbers for the vg30e. i dont have the FSM and i've been on the web for a while trying to find out. several of the search functions on forums havent been working.

I blew a radiator hose this weekend on my 91, and overheated. i got everything fixed and did a compression test to make sure things werent too screwed up. here's what i got: 115, 100, 120, 110, 120, 110 (1-6 respectively). i know #2 looks a little low, but im just wondering the normal compression, low, and the variance between cylinders?

Thanks,
Avery

 

According to the '94 FSM, compression in psi; Stnd = 173, Minimum = 128, differential limit between cylinders = 14.

I don't know if these are the same for the '91 or not.

 

^ yep just did the test on the motor I dropped in mine same.

 

I'm just wondering how long do you guys crank starter for this test?
I mean I did the test but I was getting different results depending on how long I cranked the starter.

 

According to the FSM:
1) Warm up engine
2) Turn ignition switch off
3) Release fuel pressure
4) Remove all ignition coils and spark plugs
5) Disconnect power transistor harness connector
6) Attach compression testor to cylinder
7) Depress accelerator pedal fully
8) Crank engine and record highest guage indication
9) Repeat for each cylinder
10) If compression in one or more cylinders is low, pour a small amount of engine oil into cylinder through spark plug hole and retest.

 

This is what I'm talking about. You can crank engine for a second or for 2-3 seconds. And the compression is different depending on the duration of cranking.

 

The highest compression you get within those 2-3 seconds is your compression.

 

you crank as long as it takes for the gague to peak. It shouldent be much more then 2-3 seconds though