Compression test question

[rinmak]

Hey all,

Just found out the compression on all my 6 cyls.

1. 140

2. 140

3. 150

4. 140

5. 150

6. 140

Now I know that aslong as they are all somewhat even then you got no problem but whats considered even?

Is the 10 difference a problem?

What does the difference amongst them indicate?

Edit: Car has 115,000k's on the odo, assuming their genuine does it sound like the compression is aging right?

[blind_elk]

I would say that the engine is in pretty good nick for 100k+.

I think acceptable variation is +/- 10%, so I would guess anywhere between 130 and 155 would be acceptable. (average is around 143)

[blind_elk]

Just had a lookup on the R32 GT-R workshop manual. Specs are (@300 rpm):

Std: 171 psi

low limit: 128 psi

variation between cylinders: 14 psi (not clear if this is avg +/- 14, or hi - lo = 14)

Would imagine similar numbers for the other RB engines.

Just FYI, method is:

Remove all spark plugs

insert gauge in plug hole

Full throttle

crank