series 1. can cracks in these be welded and if so how well does the weld last?
You can braze them with oxyacetylene after notching the cracks a little, but because of the mass of cast iron it takes a lot of heat. It’s a very effective, permanent repair.
I’ll add it’s best to preheat the entire manifold up, on a BBQ grille, or in the wife’s oven.
Helps the brazing to go on better… may not too good on your marriage…
Better than my wire wheels in the dishwasher! She still doesn’t know!
Question: how did this happen? I’ve not heard of the cast iron manifolds failing, other than the porcelain coating flaking off.
When I got my E, one manifold was cracked (and actually an ear had broken off the clutch master cylinder). There was a company that specialised in tricky welds, and did repairs to very large industrial kit. Not sure what they did in the detail, but it was welded not brazed, and has lasted 27 years and counting.
do you know the kind of weld he used?
No, sorry Tom. I just gave it to them and left them to it. When I got it back, I had both of them re-enameled. Too bad that didn’t last as well as the weld 
. I think the key is to find someone with a good track record of welding cast iron. As I understand it, the preheat and cool down processes are critical as well as the actual weld. Probably not a diy prospect. Nowadays probably easier to get new or good secondhand one.
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True, plus the use of the proper filler rod.
Definition of cast iron: a series of cracks, held together by PFM…
When I bought the FHC an ear was snapped and each manifold had a crack on the side facing the engine. When I bought the 2+2, same thing; cracked manifolds.
I took the FHC manifolds to a local machine shop and was quoted a price of $125 to repair both. IMO, that’s a very fair price to have it done professionally and correctly, but I opted for new, uncoated manifolds from SNG. I’ve no regrets about that decision.
I’ve had mine welded and they have lasted for years. Not every welder can do it - it’s a specialized skill…
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Really, brazing cast iron with oxyacetylene isn’t all that difficult. Notch the crack then, as Wiggs says, preheat the entire manifold (I used a rosebud), replace the rosebud with a large tip, crank up the flame good and hot and go to town.
I repaired my front manifold decades ago and it’s still holding up. I also had a couple of stripped stud holes which I filled with braze, filed down, drilled and tapped. Also still ok, though that manoeuvre was a little tricky keeping the molten brass from sagging out of the hole.
Edit: maybe a better video How To Braze Cast Iron - YouTube
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That’s why, for non-structural purposes, I recommend it. It’s really easy.
SNG just announced black PAINTED manifolds new !
Check it out as an option
I have 3000 miles on 4 months on mine from Sng not one craxk
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Not successfully. Not successfully.
I didn’t consider repair at all, as an option on my front manifold.
Not sure if this is what is meant in previous comments about a snapped ear. The nut is missing from the bolt on the opposite corner from the broken one, which I guessed could result in enough loss of structural integrity to enable a break like this.
I looked on an auction site, and used manifolds are readily available, but maybe I should just get a new painted one, as just suggested.
I think I have a decent spare, yours for the shipping.
PM sent. Thanks a bunch Paul!!