just wondering...i know i can answer own question within time, but i just wanted to see if anyone has had this problem after installing cams or a new head.

problem occured after i installed my newly ported and polished head along with some 62402 cams. before install compression checked out at:

1 - 185psi
2 - 185psi
3 - 182psi
4 - 187psi

after new head and cam install:

1 - 175psi
2 - 175psi
3 - 175psi
4 - 175psi

i was wondering since the head was vacuum and flow tested good...if it's the overlap in the cams/LSA?

oh this is on an LS motor.


Modified by shermanyang at 5:15 AM 9/20/2004

 

why'd u go with the 402's? u shoulda at least went with the 403's or 404's. thats unless u got the 62402T and ur turbocharged?

im guessing that it would cause some compression loss due to u installing those cams, but not toooooo sure

 

nevermind, just seen your signtaure: TURBO!

 

yeah i should of went with the 62402Ts but i got these for free from cousin since he's parting out his LS setup. I looked at Crower's website and these cams are for agressive turbo/nitrous applications without valvetrain upgrades. so i'm assuming that they should work on my setup even though i have upgrade valvetrain parts. i'm gonna have to try to tune out the LCA to see if that's the problem.

 

still good numbers man... we should try a street tune with your stock cams on the new head just to see how it runs.. i wouldn't be surprised if we get an extra 5whp with less overlap on the lift and duration..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by redlinetuning &raquo;</TD></TR><TR><TD CLASS="quote">still good numbers man... we should try a street tune with your stock cams on the new head just to see how it runs.. i wouldn't be surprised if we get an extra 5whp with less overlap on the lift and duration.. </TD></TR></TABLE>


that might be true...but i should of been able to tune that out. i honestly think that my valve clearance is too tight. i'll have to readjust my valves today...but i just got home from work and my engine is still freaken hot.

 

ooh.. i heard what happend saturday night.. yo! maybe i'll see more action this weekend ey? LOL


you'll have to show me how to do that valve adjustment sometime.

 

Any time you alter the duration, lift or timing of your cams you might lower the compression test results. With aggressive cams, the intake valve stays open at the beginning of the compression stroke, and air will leak out during compression at low engine speeds. Very little (if any) will leak out at high engine speeds because the air flow doesn't have enough time to reverse directions. This is one reason why aggressive cams lose low end torque.