Crack in engine block below exhaust manifold
 

My 403 block exhibits a fore and aft crack in the area below the exhaust manifold. I understand this is part of a cooling jacket. Rumour has it that this can be successfully cold repaired. Could members share their experiences and repair process please.

RonP

On mine there is a thick metal plate shaped to fit snugly against the block face, a row of bolts around the periphery into drilled and threaded holes in face have secured it there since the late fifties.

I had an 85 series block successfully repaired many years ago. Much depends on the length of the crack and the thickness of the casting around the crack.
A search on the web for "metal stitching" should set you in the right direction. I was advised to have the block ceramic sealed once the repair was made.
Have a look at castingrepairs.com for pictures of the process.

Cold stitching
 

Cold stitching can work. If you look at the web guidance nowadays there are fancy tapered taps and plugs available which look really good.
Nearly 50 years ago, I did a similar crack in the low-tech DIY way, with brass rod and ordinary taps and dies (probably 2BA) with overlapping plugs set in with Locktite and peened over with a little hammer. Seems to have held up OK since then (though, to be fair, the car was in the garage for a very long time in the intervening years).

I had my 403 block stitched by Nick Hood of Surelock. Nick's company is now part of Castingrepairs.com. The car has only done a few miles since I had the work done, but so far so good. My repair was one of the biggest he had done on a Bristol 2 litre block - he had to cut out a large L shape, then make a repair section out of cast iron sheet, then stitch the repair panel in. He ceramic coated the whole cooling sstem by circulation after the repair was completed, then pressure tested. I posted this on this very forum some time ago, with photographs. The post title was "Water leak from block on 403 engine". General note - it really is worth searching previous posts!!