Hi all..
newly built motor,
Cylinder no 3 had compression for 10 sec then its gone..
compression test shows 0 psi , which is not possible ...
took out the head and the valves where prefect..
leak tested all of them.. all where ok.
installed the head back
checked the timing it was ok.
OEM lifter cleaned and bleeded 2 or 3 times..
before starting the engine the cylinder # 3 showed compression above 160 Psi.
started the engine and same issue came back in 30 sec.
gsc s2 cams
head is from another engine which was working Perfectly untill the engine had pistons issue..
complete OEM head except S2 cams and gsc beehive springs and retainers..


9 days and counting...


HELP!

You need to leak it down to see where the compression is escaping.

Check to see which valves are getting stuck open

Leak down test with head on engine.
May want to check to see if the lifters are bottomed out and hanging the valves open. If a valve job was done and the seat has been moved up , it may need additional work to the valvetrain .