Cracked cylinder
 

Customer brought a car in a few months ago with new 383 chev and a flat cam. I took the motor apart, and crank was ground up, bearings shot etc. Then I spot a crack in the cylinder wall of #8. It's up in the dry part, but crack is 3/4" long and heading up the cylinder wall. I tell her I wouldn't want to use this block, and that the crack will probably just keep going.

She sends the engine back to the builder. Builder calls it superficial and rebuilds the motor. We got it back and i'm told to put it in. Hopefully this pic will show what i'm talking about. What do you all think?

I would get paid in full for your reinstallation work on that motor before you even pick up a wrench to do such!

That crack is going to keep on spreading up info the Bore section in a given amount of time, and I would tell that person with absolute certainty that the warranty for the whole motor top to bottom ( including Cam and lifters ) is with the builder and his word that the motor is ok.

Why didn't they just sleeve it and get rid of the problem.

I wouldn't want it in my car unless it was fixed right.

Up to owner.



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Builder didn't grind the crack, after your observations. Inconceivable. Musta be a quickie shop.

Something tells me the builder who she sent it back to got to aggressive with a die grinder on the block to clear the 400 type crank.

Many SBC have a thin area in #8 at the back side. The edge looks rough (no die grinder work) and they usually don't crack there, but that block would never be used in any build leaving my shop.

Since you are only installing it, that should relieve you of any responsibility of the build. All the same make a note of it on the invoice and keep photo evidence to cover your assets in case of possible future legal action.

I actually have a 455 +.030 block that has the same type of crack in it. It showed up after it was bored, and I questioned it. I also got the same answer, that it was fine, from the machinist that bored it. He assured me he's seen many othe blocks with the same type of cracks. Just put it together, and it will be fine. This guy has run his own machine shop since I was just a kid, my father had him do machine work for him on an old Jeep Hercules 4 cylinder back then. He's probably bored thousands of engines over the years.

I've never assembled this 455 engine, because I feel it is compromised. The engine was bored in 1980, and it still sitting unassembled.

Mine appears to have some degree of core shift in it from some of the appearances on the bottom edge of the cylinders. I've discussed it with some other people, gotten answers from just grind it out with a hand grinder, to sleeve that cylinder. I've never did either, because although it was never sonic tested, I feel it may be thin on one side of the cylinders, because of the evidence of core shift. But I could be 100% wrong, and it could be fine. I've just never wanted to trust it, and end up with a big pile of scrap metal. The parts were expensive at the time I purchased everything.

It was intended to be an engine for my dirt track car, with RA IV heads that were ported, and a brand new set of SD rods, (best option at the time, and brinell hardness tested) but all the brand new parts are still sitting, and I've never assembled it because I really don't trust the block. It's all balanced, and ready to be put together. I just have reservations about it.

I have other 455 blocks, I probably should just have another one bored and put everything in another block.

I've already had one of the thin cast 65 389 blocks that was bored + .060 collapse a cylinder wall, and the piston ended up inside of the water jacket, completely destroying the rather expensive engine. After that incident, I guess I'm gun shy............:doh:

So it had a flat cam, chewed up bearings and a suspicious looking crack
and it went back to the original builder?
That's a time bomb waiting to go off again. Good luck.

Flat cam was a combination of the owner and builder's fault. The owner because she was periodically starting it and letting it idle in storage. The builder because the AFR heads are set up for a roller cam and he put a flat tappet in without changing springs or touching the heads. This time she at least went full roller on the cam + rockers, so not worried about it going flat again. But I can't believe they'd let that crack fly. I figured they'd at least sleeve that hole. Builder didn't even send a new oil pump. I went ahead and put a new one in. Gears in the old one have tons of pits and grooves cut in them. I'd love to know what kind of shop this is, but she hasn't even told me the name of the place. Just that it's in Spokane.

Tell the owner that your not happy with it and no free labor if it gives out. I would note that on a signed receipt. CYA!

Pressing in a sleeve without drilling the ends of that crack out first will only serve to load it more and open it !