i just did a compression test on my 96 b18b (150k) and my numbers were
#1 - 160
#2 - 150
#3 - 145
#4 - 160

i read in a few different threads that numbers will vary on quality of the tester and altitude. the altitude here is 3300 ft above sea level. do you think these numbers would be safe to boost on?


Modified by NuclearB18B at 3:54 AM 7/2/2005

 

I don't much about compression, but it'd make sense that it'd be lower than a B18C1, B16, or B18C5 because those are higher compression engines.

Being a B18B, I'd *imagine* a lower compression would be about average. I did a compression test a few weeks ago and I had about those same numbers on my LS. I've got 9:1 compression pistons as well.

So, either we're both in need of a rebuild or the compression is about right.

 

did you have it WOT?

if so, i'd say you need to do a leakdown test as those numbers are low. Although all guages read a little differently.

I did a test on a customer's car, b18a with who knows how many miles on it, it was 190,190,210,190. and he used to spray it back in the day. So i would say the rings are getting tired.

 

Is the engine warm?

 

i would agree. go back and do it again, warm with the throttle wide open, and if they are still that low, a cylinder leakage test is in order.

 

Those numbers seem pretty low.

I would do another test, make sure the car is completely warmed up and the test is done at WOT.

My d16z6 with 106k put down 190,200,200,195 after 8 months of boosting.

 

thanks for the replies.

i performed the test with the engine at near operating temp and with wot. some other threads i've seen seem to indicate that these numbers are actually fairly normal. i'm going to do a leakdown test when i have some more time. either way, the engine will soon be replaced with a built one

 

Compression should be around ~180 psi for the b18a/b

Those numbers are low, but still fairly consistent. Could be the tester itself.