I did an engine OH on my truck, now that I have it all together, she wont start. I have zero compression on all cylinders. I know I installed the rings correctly and I used a different compression tester and I still have no compression. Any ideas?

 

Um something is a miss. The rings are the only thing that can do that.

 

No, holes in the pistons, valves held slightly open from too much lash, too long of pushrods, cylinder wall failure, cylinder head failure, severe head gasket failure, can all cause zero cylinder pressure.

Hopefully all the failures I mentioned aren't your issue.

 

Check pushrods length.

If you are running the eddy heads, you have shaft mount rockers, right? Did you buy adjustable rocker arms? Did you torque them too far past zero lash?

 

97 is right though, rings could definitely be the problem. Are you 100% sure you used the correct rings?

Assuming you have the correct rings, did you prime the engine with oil before startup? If there is zero oil on the rings it's conceivable that theres leakage

 

also - timing chain could be out of time, such that valves never close when piston is up.

 

Even if there weren't any rings, you would get a bit of compressions.

I am going to lean toward cam timing is off, or, pushrods are too long for the application.

 

Pull the valve covers off and rotate the engine by hand to observe the valve operation. This helps to have a buddy rotate the engine while you check the movement of the valves on each cylinder. Rotate the engine to 0 degrees, or Top Dead Center for cyl #1, and make sure both valves are fully closed on cyl #1.

If this doesn't work, I would do as the others suggested and check push rod length.

Good luck!

-JT

 

I loosened the roller rockers and now I am getting compression, 150 psi. The pushrods are the same as before when it was running. Maybe my valve adjustment is incorrect or the machine shop did a bad job on the cylinder heads. I know the timing is correct because #1 piston is TDC and rotor is pointing to cylinder# 1 on distributor cap.

 

do you have adjustable rockers?