71 240z strange overheating/cooling system problem.

[Mark Maras]

I'd add a quick compression test along with the rad.

[tzagi1]

Hold them horses.....one disaster at a time.

[rcb280z]

 Get this kit and test for cylinder gases in the coolant system. That'll tell you if you have a HG problem.

[David F]

I believe you warm the engine with the radiator cap off (so you dont have to open a hot radiator) you should be able to see bubbles in the coolant if the HG is leaking.  But, a leaking head gasket will certainly cause the overheating issue...

[tzagi1]

Radiator got checked by a local shop...get a clean bill of health, tried the block test...sure enough turned yellow in aprox 20 seconds of hot running.

I guess sitting for 20 years didnt do the hg any good.

Off with her head then!

[esmit208]

18 hours ago, tzagi1 said:

Radiator got checked by a local shop...get a clean bill of health, tried the block test...sure enough turned yellow in aprox 20 seconds of hot running.

I guess sitting for 20 years didnt do the hg any good.

Off with her head then!

Since you have everything apart maybe it would be a good time to install that Stage 2 camshaft!

Edited December 14, 2017 by esmit208
Mispelling

[esmit208]

3 minutes ago, esmit208 said:

Since you have everything apart maybe it would be a good time to install that Stage 2 camshaft!

And also I almost forgot a new exhaust header w/ emission plug bunge. I case you forgot. Have fun!

[tzagi1]

The cam is a 276 duration by Camonics, The head is ported and polished....nothing is wrong with the header.

Thee only part I'll need is a $20 head gasket...hopefully.

[tzagi1]

Update: pulled off the head, found the gasket to without flaw, took the head (E31 BTW) to the machine shop to be resurfaced, got it back and was told they had to take 8 thau off...question is do I need shims?, the history of the head is kinda unknown, I remember getting it at pick and pull (it was ported and polished already) but I don't know if it was resurfaced in the past.

[madkaw]

If you don’t know how much them what shims would you use. You could measure the head thickness and figure from there- but I wouldn’t bother . I’m running .050 cut on my 31 with no shims , but cam gear advanced and chain guide adjusted .

yo

[madkaw]

I don’t see any comments regarding the clutch fan assembly. I also think you remove the freeze plugs at this point and get all the rust out .