I was wondering if a leakdown test could be achieve by pulling out all my pushrods thus closing all the valves and eliminating the need to get piston to tdc? This just seems easier than doing each cylinder 1 by 1 and having to crank the motor given the lack of room. Seems like finding tdc is kind of an educated guess rather than an exact science with heads still on and motor in car.thanks

 

Piston does not have to be exactly at TDC, just as long as both valves are closed. That is, on the compression ( not the beginning of this stroke) or power stroke (not the end of this stroke). After you have tested a cylinder turn the engine 90 degrees and test the next cylinder in the firing order. If your car is a manual ensure it is in gear to stop engine rotation and the park brake is on. I didn't and my car suddenly shot forward.

 

piston is a tdc just so the air pressure doesn't push piston down. you want every piston a same spot so you are comparing apples to apples.

 

What im trying to figure out is if i will get the same results on a leakdown test if I pull my pushrods out? The valves all will be guaranteed closed at that point instead of hoping that they are indeed closed.

 

FWIW that's how I do it. I think removing the pushrods/rockers is the only way to know 100%.