So I am doing a compression test on a b16a motor that is out of the car on a pallet. Cylinder number 1 gives me 210 psi. Cylinder number 2 yesterday gave me 110 psi, and today about 195ish. Cylinder number three I'll wait to tell you on. Cylinder number 4 like number 1 is a perfect 210 psi match.


Now both yesterday and today, cylinder number 3 reads well over 300 psi!!! What the heck would cause that?

I'll tell you what we did to cylinder 2 and three yesterday to see if we could get better numbers then 60 and 90 psi. We poured about a teaspon of oil in each cylinder, to see if it would make a better seal between the rings and the wall. We then got 110 psi on number 2 and over 300 on 3.

Today number 2 is at a healthy 195ish, but 3 is still an insane 300+. What could be the cause of this?

 

what are you spinning the motor with?

 

the starter of course, hooked a battery up to the starter.

 

anybody have an idea?

 

Are you lettin the car warm up before doing it ?

 

"a b16a motor that is out of the car on a pallet"

Don't know what would cause the 300 psi reading though. Must have something in the cylinder such as a ton of carbon???

 

keep the tbody open while doing a compression test. you get skewed numbers if you dont.

 

:sigh:

 

compression test must be done with all plugs removed, throttle open, and engine warm

http://www.c-speedracing.com/howto/c...t/comptest.php


[Modified by EVOCELICA, 8:00 PM 2/18/2003]

 

one time,
the reason your compression is so high is because of the oil you have added.
The more oil you pour into the cylinder, the higher reading you will get. Test this for yourself and see.

Just crank it over for a short while to remove some of the oil.
#2 has only 110psi, then you have a problem. Just use this as an excuse to throw in some forged pistons before you drop the motor in.