Weird boost leak test

[beansblacktsi]

I did a boost leak test today because just replaced a few gaskets and it will pressurize to about 5psi and then the cam gears start to spin (but really slow) I stopped as soon as I do this and right around the cam gears theres a little air leaking around there but no where else. Is this normal? How can I fix? Thanks

 

[kenamond]

How much pressure did you put in it? And you should pull the oil fill cap off when you BLT so that you don't overpressurize the crankcase.

 

[beansblacktsi]

My gauge said 5psi and I will try it with out my oil cap on. Ive tested my car before and this has never happened.

 

[kenamond]

I wonder if the motor was just really close to wanting to turn over, and applying boost pressure to the cylinder with open intake valves nudged it over that threshold. At 5psi, you surely aren't hurting anything. Try it again and see what happens. I was initially thinking you were maybe putting 100psi into it by accident

 

[tbonitz301]

Make sure that you are 30* past TDC. So you dont hurt any valves.

 

[FORMONTOYA]

Make sure that you are 30* past TDC. So you dont hurt any valves.

Not being set on 30* ATDC will NOT hurt anything in the engine (as long as you are not shooting some ungodly amount of pressure).

It is recommended to be at 30* ATDC so that the 4 cylinders are closed from intake to exhaust. Either a set of intake or exhaust vales in a cylinder (depending on which cylinder you're talking about) will be closed at this point of rotation so the pressure doesn't go straight through the intake mani-cylinder-out the exhaust mani.