Thread: 400 SB cracks

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I have a crack in the upper deck between the cylinders in the center head bolt hole. Is there any fix for this or is the block scrap?

If you were desperate, you could probably get away with cylinder sleeves, otherwise, it's worth a coupla bucks to a scrapper.

Proabaly not a good idea to sleeve the motor if its next to the head bolt. Due to the tension, it seems to me that the motor will just keep cracking. Might want to look into another block.

Boat Anchor

Check these guys out: www.locknstitch.com

At the bottom of this page, there are 3 links to pictures of repairs on cast iron: http://www.locknstitch.com/Services.htm

What's this? An engine with cracks extending through the cylinder head bolt holes? http://www.locknstitch.com/7042_waukesha.htm

The crack can be repaired. I have a 406 in my S-truck that had a similar crack. Because it was free and I have a complete machine shop. I bored out the head bolt hole. then threaded the resulting hole with 5/8" fine thread. Then installed a 5/8" fine thread bolt with the head cut off for a plug. Using an epoxy sealer around the threads. When it was set, I drilled the head bolt hole in the plug and threaded it. Then I drilled and tapped the adjacent water holes, plugged and redrilled the holes. Then decked the block. It has been in there for over a year. No problems.

I have used the lock n stitch on inner lifter valley cracks with great success!

a machine shop may be able to repair it depending on how bad it is otherwise i would just scrap it

it could be repaired effectively using bobcrman's method--- thats the same method thats recommended for strengthening the deck suface around the large coolant passages in the deck surface---tap, plug, deck, and redrill---definitely will work--although i wouldnt recommend this repair if motor is to be built for over 500hp---i have a block in same condition