GN1 heads ???

[Black Car]

Does any of the exhaust header bolts go through the water jacket?
A friend on mine purchased a 87 GN with Champion GN1 heads on it. He had to replace his exhaust gasket on the driver side and when he removed the lower bolt to #3 cylinder, antifreeze came out.

I know the stock heads don't do this. Never worked on GN1.

Is this normal

Gary

 

[Nick Micale]

Sounds like he cracked the head with too long a bolt?

Exhaust holes do NOT normally go into water on the GN-1's. The stock header bolts are usually too long and will bottom out when tightened.

Like threading into most aluminum parts, the exhaust manifolds should be done with studs. To keep from overtightening, yet have a good seal, I always use a compliant gasket like the Felpro 1400. Have had copper gaskets, as well as sealing with silicone, leak, when 1400's don't.

 

[Grumpy]

hey Nick we used the stock bolts on them an they were fine...I have also heard about that problem to!!! I measured the bolts before we used them....

 

[REEDOG]

I had the same problem with mine. Just as Nick said the fix was to use studs and apply a sealer to that particular stud. I made the studs from stainless allthread. The previous owner of the heads had nearly stripped the header bolt holes, so I threaded them to thier full depth with a bottoming tap to create fresh threads. Now instead of the aluminum taking the abuse of running bolts in and out, the studs are the wear item. I also had the cracking problem for a while but after many head removals I've finally got everything squared.