Does anybody know the reason why can the exhaust manifold break in half?
We failed to weld it...
May be somebody has the spare one? My friend Constantine Mandylas heads from US to Russia in December, so he could bring it.
Well, old cast iron that gets hot repeatedly can also get brittle, so these things happens. Another common issue is bending over time, since the weight of the exhaust pipe tend to bend the rear part of the manifold when it's really hot. A bent manifold doesn't line up with the ports in the block, so it can't be used with the proper steel glands and copper rings - with accessory three-in-one gaskets they can be used for some time more, but the bending will continue even faster and eventually it'll leak.
Straightening a bent manifold while heated red hot may work, but there's a big risk it'll break just like yours when bending, so thus it's hard to find good used exhaust manifolds - the threads for the nut is another area that gets rusted and worn with age and on many old manifolds it's hard to get any nut to fasten tight enough.
Fortunately good reproductions are available from the vendors like Lang's: https://www.modeltford.com/item/3060B.aspx
They do ship overseas to Sweden - hopefully to Russia too?
Vee out the joint, clamp it straight and braze it.
Nope. Never seen one break like that. I've broken a few at the pack nut threads when I was young and stupid and tried to remove a cold pack nut. Now I'm not young anymore.
My first T as teen came with a manifold cracked in the middle just like that. Dad found an old guy who welded up the manifold and made it one piece again.
The weld joint was big all around puddle and looked bad but worked. My guess is running for years without the support steel glands in the ports causes bending and final cracking.
We have them in stock new, Bob
I like that, George. I'm at an age where I can use it myself.
George & John - I used to be young and stupid,.....but now I'm old and,....well,....oh, never mind......!
Usually they break like that trying to straighten them. After heating the bend red hot, the weight of a large wrench is enough to bring it back down.
I haven't had one crack clean through like that, but I have had one literally explode like a grenade when trying to undo a packing nut with a cheater bar.
I think it has to do with how fast they were yanked from the casting box. Cold shock locks in stresses that can wait 100 years to get out.
Perhaps the manifold bolts were not tight over the years and therefore allowed the casting to warp in the middle. When being re-installed and re-tightened the stress was excessive and caused it to crack. I had a Studebaker V8 exhaust manifold that was warped .020 a perfect receipt for cracking, it was ground to fit flat.