I got another 400 block that when honed showed a big crack in one of the cylinder walls. It starts about 1 inch down from the top of the cylinder and goes 4 or 5 inches down to about 1 inch from the bottom.

I was ready to scrap it but my machinist thought it could be sleeved. Do you think it would be OK sleeved with a crack like that?

Thanks

Also, on the 400 that Im doing now, i took it to my machinsit, and he checked it. he said it had .018 bore wear. I was thinking of boring it only .020 instead of .030 in case I needed to bore it agian some day down the road.

Should I bore it to just .020 or go ahead and bore it .030. Im thinking. 020 would also leave the walls slightly thicker.

Of course it can be saved.

On the other hand, if it's just some junk block, you can probably come up with some other junk block that doesn't need a sleeve, for less money than sleeving that one.

Just because a thing is possible, doesn't always mean it's the right thing to do.

Piston selection in those off-the-wall sizes is pretty slim. Locate the exact pistons you are intending to use, in that odd oversize, before you have the block finished out to it. Otherwise, you may find yourself having to pay for boring and honing.... twice. Once to .020" over, and then once more to take it to a size where you can actually use it.

I usually don't like putting sleeves on when I could buy another block for the same price or cheaper. I have my 400 bored over .040 (408) and the walls arn't very thin.

Don't like sleeving 400's that are cracked.
I have done it but the sleeve gets very close to the bolt holes & tends to crack into them.
I have sleeved a number of them that had damage but were not cracked with a thinwall sleeve as they are getting a little hard to find.

If the other block is worn .018 it will be almost impossible to do it correctly at .020.
First, you will need to set up off the wear which will not be centered & second, you need about .005 to hone after boring.
Just bore it .030 & get it right the first time.
If it will bore to .020 SRP has almost every piston they make in this size.

Ok, thanks guys. Well, normially I wouldn't even think of sleeving a block, but 400's arent just easy to come by these days, and when you find them the seller usually thinks there made of gold. I got both of these from the same guy, both for $125, one is good, the other isn't. I think I did alright on price.

I guess I'll just take my good block out to .030 then.

Thanks

Is it true if you use short sleeves the engine will run cooler?

Originally posted by onovakind67:
Is it true if you use short sleeves the engine will run cooler? =
Mike,, you gotta quit smokin them funny cigarettes :D
:rolleyes:

id have one sleeved in a heart beat/nothing wrong with a sleeve if its done right and kieth black hypers also come in 20 overs thats what we did to my brothers last 400

Originally posted by JUNK YARD DOG:
id have one sleeved in a heart beat/nothing wrong with a sleeve if its done right and kieth black hypers also come in 20 overs thats what we did to my brothers last 400 =
Sorry but I must completely disagree when it comes to a 400 block.
In a 400 there is a definite problem with sleeving a cracked block.
You need to use the thick sleeve if the block is cracked to any degree to have enough wall for any semblance of support & this puts the sleeve very close to the head bolts.
For info, even with a "thick" sleeve you have less than .125 wall.
They then have a habit of cracking from the head bolt to the sleeve.
As I posted above, I have done a LOT of these & if it is a thin wall sleeve (.062) to save a damaged cylinder it's an ok deal.

That said, depending on where the crack is, I would prefer to not use a sleeve in a badly cracked block in a performance application.

This does not really apply to a junkyard rebuild that will never see any kind of cylinder pressures :D

mike i will agree i had also rather use a block that has not been sleeved ,but i would not be afraid of a sleeved block .i have two now that i run or have ran bracket racing with no problems.one with thick wall sleeve but i have pored it also .the difference in us is you build racing engins for other people and i build them for myself to race .that said a good machine shop will tell you if it can be sleeved or not before you throw it away

Well, like I said- I just cant throw a 400 block away, there to hard to find around here. And I got another crank for it, and few other goodies left over. I wish it was a 350, I could just get another block for $50.

I know some sleeved engines are fine and some are crap. I guess I'll stash it until I get the nerve to gamble with it.