Z28 exhaust manifold crack opinion

[mhm1966]

Kevin,

I am glad you are using welding material for the USA. The stuff made in China is junk and will never provide an adequate weld. You should also make a jig to mount your exhaust manifold in so that when your done welding the holes in your exhaust manifold lineup with the threaded holes in your head.

[rszmjt]

Originally Posted by mhm1966

Kevin,

I am glad you are using welding material for the USA. The stuff made in China is junk and will never provide an adequate weld. You should also make a jig to mount your exhaust manifold in so that when your done welding the holes in your exhaust manifold lineup with the threaded holes in your head.

Chances are you will have to drill the bolt holes out a little bigger on the end cylinders #1 & #7 anyway, those style manifolds always seem to shrink in from heat.

We used to see that sort of cracking on similar design exhaust manifolds from mid 70,s Chev trucks that had propane conversions.

[KevinW]

Originally Posted by rszmjt

Chances are you will have to drill the bolt holes out a little bigger on the end cylinders #1 & #7 anyway, those style manifolds always seem to shrink in from heat.

We used to see that sort of cracking on similar design exhaust manifolds from mid 70,s Chev trucks that had propane conversions.

Thanks for the tip. I will test fit the manifolds and see how they fit before welding. I can always hit the bolt hole with a die grinder.

[rszmjt]

Originally Posted by KevinW

Thanks for the tip. I will test fit the manifolds and see how they fit before welding. I can always hit the bolt hole with a die grinder.

Very hard to die grind that length of hole, just use numbered bits and drill it slightly larger till bolts go in if the manifold has shrunk.

[KevinW]

Originally Posted by mhm1966

Kevin,

I am glad you are using welding material for the USA. The stuff made in China is junk and will never provide an adequate weld. You should also make a jig to mount your exhaust manifold in so that when your done welding the holes in your exhaust manifold lineup with the threaded holes in your head.

Hmm, that might be tough. I have to cool this down slowly, so overnight in a bucket of sand is the ticket.

I have been working on the smog tubes and the un-cracked manifold. Once done with that I plan to switch to the nickel MIG wire and try it out.