I just picked up a 400 SB for free. The guy told me that it had blown a head gasket between number 4 and 6 cylinders causing the block to erode there about a 1/8 deep and 1/4 wide. This block is standard bore and I can't feel a ridge with my finger nail so I hate to scrap it but also don't want to put more money then it's worth into it. Any sugggestions would be very much appreciated!
Welding a 400 SB
SS 427
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I just picked up a 400 SB for free. The guy told me that it had blown a head gasket between number 4 and 6 cylinders causing the block to erode there about a 1/8 deep and 1/4 wide. This block is standard bore and I can't feel a ridge with my finger nail so I hate to scrap it but also don't want to put more money then it's worth into it. Any sugggestions would be very much appreciated!
First thing you need to do is have it magnafluxed. About half the time we see that, there is also a crack or two caused by the heat. If its not cracked, it can be welded, but you need someone good to do it. The trick is to not get the weld material down in the ring travel area. Needs to be welded in such a manner that it does not leave any gap between the old material and the weld, or it will just repeat itself. As far as 2 sleeves go, that would be an option, but they would have to be thick wall sleeves for the gasket to seal properly and I am not real fond of doing them in 400's, especially 2 next to each other.
I really dont know if it's worth the trouble or not.
I really dont know if it's worth the trouble or not.
Thanks for all the quick responces! I'm not going to through it away yet. I did notice that there appears to be a small crack between cylinders as well but does not go down into the bore. I figured I'd wait and see if someone else has had the same problem and had good luck welding it up and machining it. Would I be better off taking it to a machinist or welder first? I know how to weld but not something like this. Thanks again for the information.
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=BillK said:
=BillK said:Mike,
Thats what I get for giving the "long" answer
Hi Bill,
Not long,,, detailed,,
=
And I agree, you want to check it close but I have had a number of these done with with cast rod & seen them done with braze & spray weld with no issues & a couple are in circle track deals.
I see very few that have been run to to point of destruction at the block.
Usually seems to torch the head the most for some reason.
Check with your machinist as he may do it or have someone who does cast iron for him.
We have a couple of folks out this way who specialize in this stuff & I have sent blocks to them to weld & then done the machining.
A lot of welding shops will not know what rod to use & you won't be able to machine the damn thing,,,
On second thought, I agree,,, it ain't worth it to fix & you should send the block to me so I can dispose of it for you,,, I will even pay the freight
Well Mike I may take you up on thatWolfplace said:= On second thought, I agree,,, it ain't worth it to fix & you should send the block to me so I can dispose of it for you,,, I will even pay the freight
After tearing it down I found that it had been rebuilt before, crank 10/10 and bore .030. Am I right in thinking it's done even though I can't feel a ridge? My way of thinking is even if it can be welded there isn't enough material left to machine. Now I'm thinking 383.
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7,296 Posts
=SS 427 said:Well Mike I may take you up on that
After tearing it down I found that it had been rebuilt before, crank 10/10 and bore .030. Am I right in thinking it's done even though I can't feel a ridge? My way of thinking is even if it can be welded there isn't enough material left to machine. Now I'm thinking 383.
Ummmmm,,, I'll pass this time
But I don't have an issue at .040 over. My preference is not to go further.
I have done .060 over 400's but really do not recommend them.
As it has already been bored this may make a repair to the deck a bit interesting though.
Doesn't leave much to clean up & it is going to distort the bores pretty good.
For a performance deal I would probably be looking for another block.
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