Can i check compression without cams?

(2010-05-30 09:19:58) 1. boib b Says: basicaly ive done a valve job and compression is coming up as 150, 250, 150, 150. I am trying to figure out why this is, before i take the head off again and relap the valves i want to be sure it is not because of tight clearances. I was thinking, if i can take the cams out and do a compression test i would know for sure if it is because of low clearance or poor valve seal. I just want to know if its possible to crank the engine without timing belt and cams, ie just build up compression, ie can i do it by hand? all i need is the pistons to go up and down to build pressure, thanks for any help guys!2. Grizz Says: If the tappets are hydraulic then you need to crank the engine over for a good few seconds with no spark plugs in to allow the tappets to fill up properly. You could also check that the timing has been reset correctly, although I would expect a problem across all 4 cylinders if it wasn't.

If the engine has rockers, then ensure that they have all been refitted correctly.

Apart from this, you can force air into the cylinders through the plug holes one at a time and then listen for any of it escaping into the intake or exhaust manifolds, which would denote a leak from an intake or exhaust valve respectively.

Regards

Geordie3. alan Says: No,if you do not have the inlet valves opening to let air in,how can you build up compression?4. Howard L Says: If you remove the cams you can do a leak down test which is the best way to determine the condition of the rings and valves even if the cams are on. The cranking test is commonly used only because it's easier to do, but it's actually rather inaccurate.

As far as where the leak is it might be possible to hear the leak with a stethoscope on the intake and exhaust manifolds. I never tried that one.5. Spartan L Says: A cylinder leakage test should be done on a WARM engine for accurate results. Tag: Can i check compression without cams?