ok i recently swapped the head on my ls turbo with a b16 head and after running the car on 15psi when i didnt realize that it was creeping that high i checked the compression and cylinder #4 was 145 at first and cylinder #3 was about 140 then i checked the compression again after running the car and #4 was like 130 and #3 was like 138..... then i finally got my boost creep prob down to 10psi and was gonna see if the compression was goin to drop anymore before i pulled it apart and after running it again w/ race gas (110 oct) i checked the compression and #4 was like 140 and #3 was like 130....so why is my compression varying up and down....valves bad????/valves need adjusting????? rings???? was told to adjust valves 1st and go from there... what do you think

 

Did the temp of the engine vary? When I let my engine cool down on my truck, my leakdown test varies a whole lot.

Exhaust valves seal a lot better when they're hot.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mac8008 &raquo;</TD></TR><TR><TD CLASS="quote">Did the temp of the engine vary? When I let my engine cool down on my truck, my leakdown test varies a whole lot.

Exhaust valves seal a lot better when they're hot.</TD></TR></TABLE>all the times that i did the comp tests the motor was hot... but do you still think its a valve seat prob or a burnt valve...thanks for the info

 

well i guess im jus gonna run the **** out of it till it blows so **** it....thanks

 

You hold the throttle wide open for all compression tests? Also, did you crank until the needle stopped rising for each cylinder?

 

those numbers seem low anyway.

my ls motor has compression numbers at 180 all the way across.

 

thats another thing i....did not hold it full throttle..in which i was told to do so today..but i did crank until the needle completely stoped rising in each cylinder... im tryin to get every bit of faith that i can hahaha.... thanks man