Leak-down test questions

[skid542]

I currently have the motor pulled back out of my car and am ordering my timing belt Monday. With everything going on I want to try and get a warm-fuzzy about my motor before getting everything wrapped up and turning the key.

So my question is - can I do a leakdown test with the timing belt off? It seems that I should since if the cam gears are unloaded the valves should be shut and it is really easy to tell when the piston is TDC without a spark plug in the hole. Is there anything I should be aware of since I'll be doing this with the motor cold?

I've got a compression tester and I could wait until I get the belt on and the engine back in the car to test but I feeling a leak down would be more appropriate. I was an idiot *raises hand and sheepishly acknowledges* and didn't take the old timing belt off per proceedures. I didn't feel anything out of the ordinary and I never pushed things hard, but I don't know how difficult it is to bend a valve and would like to make sure I didn't screw anything up on the DOHC heads. I've heard all this *you'll bend valves if you don't do it right and let the pressure of the cam springs unload* etc.

I'm probably just being paranoid but I'd hate to find a problem later when now's the *easy* time to fix something.

Many thanks in advance.

[Legacy777]

You can do a leak down test with the motor cold. Like you said, with the cams unloaded it should be easy to get at TDC.

When you do the leak down test, just keep an ear out for leaking air from the TB and IAC valve as well as the oil filler neck.

[skid542]

Thanks for the input Josh. I had my friend come over this evening and we tested it at 80psi on the regulator. The other dial never indicated anything less than 77-78psi on all four cylinders. With that low of leakage I didn't bother searching around for the leak and we just called it good.

Another props is deserved to Kelly for his mad engine building skills - can't wait to get it running .

[Legacy777]

Yeah that's pretty good leakage....or lack of