318ci LA

Can I run a compression test to check new headgaskets without a cam installed? I'd like to know the gaskets are sealed properly before I finish up my head swap and break in a new cam & lifter set. The valves would all be closed but there wouldnt be any intake/exhaust air moving. I dont know how that would effect the gauge.

Crap I think my oil pump driven off the cam. What about leaving the old cam in but without the lifters/pushrods?

 

Remember the Otto cycle? for an accurate test,your need to fill the cyl. ie: intake valve open as piston draws in air/fuel...AIR IN YOUR CASE
If the deck was clean & streight Ie: no old gasket pieces & no pulled headbolts& motor didn't get too hot you are using new headgaskets(gaskets have come along way)

The head was also clean,you didn't say if these heads were machined but if you followed the torque procedures I wouldn't worry..But if your still not "comfortable" get yourself a Leak Down tester...Dwell the piston @ TDC

*** Be carful if you have never used this procedure,the motor WILL rotate if not centered on the stroke &&& IF WHATEVER YOU ARE TURNING THE MOTOR WITH WILL FLY OFF!!
If there is a problem,you'll hear air comming out. another trick if you can not pinpoint the source,introduce smoke to the test you'll find it for sure!
No Worries

 

moein wichita ks
Fryingrines has some very goodinfo. also if you do have a leak you can find out if its rings or valves put some oil in the cyl and it will seal off the rings, however new ring may not seal realy well untill they have ran some. a trick i have seen to check valve seal is to set the head chamber up and very level, fill the chamber with kerosine, if a valve is leaking it will seep into the ports.

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The heads were resurfaced and pressure checked and the shortblock is in good shape. The last time I changed head gaskets they didnt seal properly so I had to tear the engine down to fix it (oil got on the gasket surfaces). I really dont want to go through that again so I figured I'd try to check before putting it all back together. But with a new cam & lifters I dont want to be cranking the engine over a bunch of times before the break-in. I dont have the hardware for a leakdown test so I'll probably just bolt it all up and hope for the best.

 

hook your compressor up like a leakdown tester and close off the valve and watch the gauge.