No compression after rebuild

[clizz3]

Well my father bought a 93 gs for a spare car about a year ago. Got head rebuilt and replaced a lot. We got it running and drove it for Maybe a month then it won't start and there's no compression. Heads off but no bent valves. So any ideas on what could be wrong?

 

[BogusSVO]

Did you check the timing belt, and line up the marks before you pulled the head?

How did you check for bent valves?

 

[clizz3]

My fault. Yes we check timing marks first. Everything was lined up correctly

 

[killer_eclipse]

I would do a leak down test it will give you an idea where the leak is... ive had some low numbers from some tired motors befor but zero compression? was that the actual numbe in each cylinder?

 

[clizz3]

I'm not sure on the numbers exactly but could this be a faulty head gasket? I've read about saying it could but I'm not positive.

 

[Dsmkauai]

So do you have 0 compression or just low numbers? The numbers will help alot to direct you to the next step. Let us know. And how do you know the valves arnt bent have to taken them out yet to check. 0 compresion usually is bent valves or huge hole in piston.

 

[BogusSVO]

0 compression on all 4 cylinders from a blown headgasket would be rare, unless the head was extremely warped.

Chances are the timing slipped and bent valves, or the alignment dowel that indexes the cam to gear sheared allowing the cam gear to slip, but will keep timing marks lining up.

 

[jayson427]

Are you sure you did a proper compression test and make sure the gauge works right? That's pretty strange to happen over night.

 

[clizz3]

Well he did a compression test and the numbers were low. highest was 50. He took the off the head and and that's how he knew there wasn't bent valves. Timing was correct.

 

[BogusSVO]

Just pulling the head off and looking at the valves is not the best way to check for bent valves.

A fluid test will tell you more.

http://www.dsmtuners.com/forums/newbie-forum/420313-how-fluid-test-4g63-cylinder-head.html

If they have a slight bend, you may not see with your eyeball

 

[clizz3]

Update: replace head gasket and runs flawless. Better than before