Help!!!! No compression in #6 cylinder

[Gordon1987]

I just did a rebuild on my m20 block and my #6 cylinder has 0 compression. Cylinders 1-5 have 160psi compression.
Think it may be a burnt valve because before I took the engine apart I couldnt rev past 2k under load. Now I can.

[Adrian_Visser]

Define "rebuild" did you do the head as well? I agree that it is probably valve related.

[Gordon1987]

I did the head couple weeks back before the block rebuild... The reason I rebuilt the block was because after putting the new head on I blew the rings

[Adrian_Visser]

Redundant double thread is redundant.

[Jean]

How many miles? Because if it's 200k? You don't need to rebuild.

[Gordon1987]

Don't know odo doesn't work.... But already did the rebuild

[QUKBMER]

If the rings are ok i would start looking at who did the valve job. Maybe the valves are not seated well?

[Gordon1987]

The valves were fine b4 the rings blew out

[!kid]

Do a leak down test. That should pin point your problem.

[nomansland92]

pull the head and have it pressure tested, im also thinking valves.

did you set the ring gap placement correctly?

[JTapper]

Do a leak down test. That should pin point your problem.

This.

A compression test is essentially worthless in this situation.

I never test compression, only leakdown.

[Gordon1987]

Trying to get my hands on a leakdown test for tomorrow. Thanks for all the inputs. I've been thinking valves too just wanted to have other inputs