SBC block leaking water internally...

[Krooser]

Local racer has a GM short block SBC for sale. Sez it's losing water and smokes. He replaced the heads and that did not fix it. He sold the heads and intake. The block has aftermarket rods, good pistons and a decent crank in it and I can buy it pretty cheap. I know the block should be disasssembled and pressure tested but I'm wondering if there are any spots I should look for when I go look at the engine. Any common trouble spots?

I have an older late model that has a good racing history behind it that I'd like to put together and sell... show car/collector kind of thing. It might be a good candidate for this project.

[rustbucket79]

If it was a straight water deal it should have a stain where the issue is.

Ask if it would fill the crankcase, pressurize the rad, etc.

[steve cowan]

I have 3 x gm blocks that have cracked around #6 and # 8 head bolt holes, a couple have been sleeved and keyserted as well, unless you are desperate I would not bother, grab a magnifying glass and good light, first place to look.

[mag2555]

Why....why would you want to buy a problem?

It makes no sence seing as your dealing with a super common SBC block and not a 52 studeabaker block!

[BILL-C]

Stock blocks usually crack in lifter valley. These cracks are very common and usually don't actually leak until they are at least a couple of inches long. When we mag a block and find a short one that doesn't show any evidence of leaking yet, we can use loc-n-stitch pins to reliably fix it in a half hour. When we find one that has a sludge line and was leaking, then that crack is usually 3+ inches long and we scrap block.

[Krooser]

Good ideas...thanks

[Krooser]

I think I can get this running for a grand or less. Use the iron heads I have in stock. I found a block for $50.00.


I couldn't do a stock rebuild for any less. I have a set of iron heads that are pretty fresh with decent springs and parts that I would use.

Having a racy motor in this old car would make it much more saleable I would think.

[smeg]

I think I can get this running for a grand or less.

Yes and you can get aides for free.

[JoePorting]

Was oil getting in the water would be the main question to ask. Ask him if the oil or water was milky. If not, should be a good block to rebuild. Probably had a water leak somewhere else and a bad ring seal.

[Krooser]

I think I can get this running for a grand or less.

Yes and you can get aides for free.

All the internals are good...and not very old. Transferring these parts to a different block is pretty fricken easy...it's done everyday. Wash, bore/hone, rewash and assemble.

I would bet most every professional builder on this forum has done just that.

[dwilliams]

For a production Chevy small block, the only place I've personally seen with an internal water leak was a crack down in the lifter valley, usually in the middle unsupported area of the water jacket.

Has the block you're looking at been clearanced for a stroker crank? Some water jackets go lower than others, and it can get very thin depending on how enthusiastic someone was with the grinder. I never did a 3.85" crank, but every 4" crank I wound up going into water and having to do a short fill with Hard Blok.

[Krooser]

For a production Chevy small block, the only place I've personally seen with an internal water leak was a crack down in the lifter valley, usually in the middle unsupported area of the water jacket.

Has the block you're looking at been clearanced for a stroker crank? Some water jackets go lower than others, and it can get very thin depending on how enthusiastic someone was with the grinder. I never did a 3.85" crank, but every 4" crank I wound up going into water and having to do a short fill with Hard Blok.

Its a stock stroke deal... I haven't had a chance to look at it. It was running when they pulled it to install a new motor. I have been informed From a “spy” that this guy had put a couple engines together fron misc. parts he had laying around hence the issues with hie engine program. Still worth a look if i can find time.