Compression test on Ls1 in C5

[Red03SVTVert]

My buddy has a C5 with an Ls1. He had a little problem and we want to do a compression test to make sure everything internal is up to par. How many PSI should I see on a healthy motor. I have searched everywhere and found nothing. Also, what is safe to be disconnected so the engine will turn over and not fire. TIA any tips would be appreciated.

[Iroc89]

Try going to Ebay and looking up Ls1 motors for sale. Usually they will have a new one or a used one and they usually tell you the Compression ratio that the engine is running.

[BlackHawk T/A]

He doesn't want to know the CR he wants to know the PSI each cylinder should hold during a compression test...

[SeVeReDiStOrTiOn]

should be in your repair manual if you have one...i think it's 175 psi. I'm having a prob finding a haynes or a chilton for our cars

[mcamp001]

i think if they are within 10% of each other is more important then the psi they are at. Of course there is a range defined, check the shop manual, but if you have one cylinder more then 8-10% out, there might be a problem

[Weezz]

I'm having a prob finding a haynes or a chilton for our cars

Having and using a Haynes or Chilton is like buying a band aid for a shotgun wound.

Pretty damn worthless.