Disappointingly (but perhaps not susprisingly!) my homemade exhaust is blowing somewhat from the flanges. Between the flanges and the head (as opposed to the weld!).

Presumably this is because the flanges aren't 100% flat against the head.

I was wondering if anyone had a solution/remedy to this other than cutting them off and starting again?

Would doubling up on the gasket and then really tightening up the bolts help do you think?

Otherwise, does anyone know of anyone selling a single 4 hole flange I could replace my four separates with. I've tried Lolocost and no luck.

What's the recommended thickness for the plate to make the flanges? Mine's currently about 8mm but if I made my own it would be hard work to cut this to was wondering if thinner plate could be used?

Thanks!

James

how about, using a gasket as a template, cutting a flange from thin material, then welding it to your existing, multiple flanges. Weld it up, machine it flat, call it good.

dave

Could you cut them off, then use another cylinder head as a jig and re-weld the pipes? That might get them square to the head better!

Nick

i made a set for pinto man in 6mm stainless so 8mm is plenty the main problem you will have is after you weld the pipes to them they distort slightly.
i countered this by milling them flat again afterwards. others have had then trued on a lathe after a length of stub pipe is welded to them.

ps if it's not blowing that much try sealing then with high temp silicone sealer.

If the flanges are flat it should be springy enough to mate with the head and once it has got properly hot it should creep should fix things --- having said that first stop check the studs aren't coil bound


If they aren't try bolting down tight without a gasket then heating each pipe in turn up with an oxy-acetelene flame to bright red.

Hi James,

When I built my manifold, I used a piece of
75 x 75 x 10 angle, match drilled as the cylinder head,
(using the gasket as a template) as a jig.

If you were to drill such a jig you could bolt your manifold to it and
heat (dull red) the out of square pipes just above the flange welds.
This would stress relieve them, and when cold, unbolt, and they should be flat.

Hope this helps.

ATB Paul G

Try exhaust paste - may do the job and save all the hassle!
Just a though,
Pat...

Make sure it is assembly paste, not gungum

Do you have a cabinet shop nearby? Wood shops often have an edge sander (big assed belt sander). As an alternative a cylinder head shop, or even a machinist may be able to true up the mating surface.

Ok, thank you for all the suggestions everyone!

Will keep you updated with progress!

Cheers,
James

I have used doubled gaskets on a pinto with this problem on a professionally made manifold before.