Z24 head shims

[formerseal5]

I have an '89 4X4 with the Z24 engine. I have replaced the block, the head is from a rebuilder. I have now put 2 new head gaskets on this engine and every time I start it, I have the same problem with the number 2 cylinder filling with coolant. I'm wondering if I need to shim the head and if so, how do I determine what thickness of shim is needed?

[Rev_D21]

Was the block decked? There has to be a groove somewhere big enough for the coolant to slip by the head gasket. That or some foreign material is not allowing the gasket to sit flush. Stupid question but you are torquing the head correctly? Bolts tightened in the correct sequence to the correct torque? There no gouging or other damage to the bottom of the head that would cause it to not sit on the block properly is there?

[formerseal5]

I have checked and double checked both the block and the head. I did have someone at the parts counter for Nissan tell me that sometimes when using a head that has been rebuilt, that it should be shimmed. Both the block and the head are from separate machine shops. I have torqued the head to specs and followed the sequence to the letter each time I have put it back together. I did attempt to use a gasket that had previously been torqued. Now that the head is off AGAIN, I will double and triple check everything again before wasting another head gasket on it. I have never heard of needing a shim for the head gasket, I mostly work on Chevrolet's. But I'm doing this as a favor for my Dad, he really couldn't afford to get this work done otherwise. I do appreciate your response. Any more suggestions?

[Rev_D21]

Yeh, I have never heard of using a shim either. Something is amiss.

[formerseal5]

The only thing I can think of is that maybe when the head is ground down, is that it doesn't allow the head gasket to fully compress and thus the need for the shim. Thoughts?

[Rev_D21]

Well if the head is ground down it should still sit flush if it was decked. It could be warped. The only thing I know will happen if the head is shaved too much is timing will vary due to slack in the chain. You can get a thicker head gasket in that circumstance. What is odd about yours is that cylinder 2 keeps getting flooded with coolant. That tells me the gasket is leaking around the cylinder as a result of not sealing correctly. Could be a distorted or bent or damaged gasket. Could also mean some kind of crack in the block. Just shooting out things that are coming to my head.

[formerseal5]

I appreciate all thoughts on this subject. To be honest, I'm a little...no, make thatva lot frustrated with this truck. I'm going to check the head and block with a straight edge again and go over the whole surface with a fine tooth comb to insure I won't have this problem again.

[Rev_D21]

I hear you, it can be frustrating but they are great trucks and we here will do our best to help you however we can.