Crack in exhaust manifold

[TRevver]

Can anyone advise the best way of treating this crack in the exhaust manifold on a 2L mk1 Vitesse?

 

Is it likely to get worse? I’ve read on at least one forum that exhaust manifold cracks can coke up over time, partly solving the problem.

 

Thanks in advance 

 

 

 

Edited March 30, 2020 by TRevver
Highlight location of crack

[NonMember]

The Mk1 manifold is a little prone to cracking, especially if the nuts at the two ends are over-tightened. They generally don't tend to spread much, though. If it's blowing, a bit of high temperature epoxy "chemical metal" might do the trick, if you can manage to squeeze it in there.

[JohnD]

If you want to weld it up, then drill out the ends of the crack and grind the rest until almost through to provide an angle for the weld to go into.  The difficult bit is that the whole cast iron manifold must be heated before welding, to at least 400C. If you can bury it in dry sand after, all the better.  A weld into the cold metal will heat, then cool the cast iron quickly, allowing it to become brittle.

[dougbgt6]

Tricky business welding cast iron, even Fuzz got a man in.

Doug

[RogerH]

No need to weld.

It is a slow growing crack and will fill with carbon etc as it grows. This will block it.

If you are seriously concerned then get it brazed. Very simple and more than good enough.

 

Roger

[Colin Lindsay]

My Mk1 GT6 manifold blew into two pieces on a run back from Doune Show; I had to replace with a stainless manifold as having it repaired was both very complicated and very expensive by comparison - John's explanation is probably the correct way to do it (possibly it could be repaired with just a hole rather than a fracture) but I was told at the time, about 2001, that it couldn't be repaired.

[johny]

Wish mine would explode and give me an excuse to put on a tasty stainless jobbie😍

[dave.vitesse]

Your manifold is from a pre-Stromberg Vitesse 6, 1962 to late 1965. The difference being the plates for mounted the Solex air-cleaner assembly.

In the short term I would repair as given above. Brazing should be considered.

Long term I would source a second hand replacement.  2 Litre Vitesse Mk1, GT6 Mk1 and 2000 Mk1 Saloon all have the same type of exhaust manifold.

Dave

[JohnD]

I agree, brazing is a good alternative, the temp is not so high, but such a large casting would need an acetylene torch to get it hot enouh to braze - your usual propane torch not hot enough.

[Peter Truman]

Not sure if it would work on a crack in an exhaust manifold which is constantly heated and cooled but an old fix for a porous casting ie pin holes was iron filings  rammed into the hole and sulphuric acid which rusted the iron filings to seal the hole.

Dad taught me that when coming into our co foundry when an old hand was suggesting that a largish casting with numerous pin holes would have to be recast. 
Peter T

[TRevver]

Thanks for the suggestions. I’ll try a repair and source a replacement for the longer term.

 

[68vitesse]

Picture is of crack in a Mk1 2L Vitesse manifold I removed, fitted a spare, not the first I've had crack, one a leg cracked all the way round. This crack has now been welded by a local welding company, he only charged me ten pounds, coffee and biscuit fund money, due to length of time he took and I had the feeling he was not 100% confident in the repair.

Regards

Paul