2 weeks ago I swapped in a JDM B20b which I bought off a guy that had a classified on this site. The owner claimed that the motor was rebuilt 7,000 miles ago with 2000 B20Z Pistons / Rings / Motor was hot tanked / compression is good / etc etc.

Anyways, just ran a compression test and the results are as follows:

170-200-190-200

On average, that one cylinder is anywhere between 25 and 30psi lower than the rest. Is this still an acceptable margin? I thought I remember hearing that anything over 20PSI should raise concern. Also, those numbers would seem high for a stock B20b, but low for a stock B20z, correct?

If anyone has any advice on what to do with this, it would be helpful. Thanks.

 

Just put a half cap of oil down that cylinder and tried again, compression went up to 185 on it. Bad ring? Or would this method raise compression nomatter what.

 

try the oil on each of the cylinders and see what kind of #s you get.

 

it would raise compression no matter what.
it sounds like the rings arent sealing in that cyl, but i would do a leakdown to be sure

 

Can most garages do that? I rent so I dont exactly have the access to a air compressor / etc

 

Ok, my car had been sitting since Saturday afternoon when I put that half cap of oil in the cylinder. I cranked my car this morning, and burned oil vapor came out the exhaust for my first 3 miles or so, telling me that the oil that i put in the cylinder didnt leak down into the oil pan over the 36 hours that it sat there. Could this be a sign that my pistons / rings are fine? Also, can most garages do a leak down test?