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i am confused
so, the good cyls are .030 over?
and you want to go .040?
carry on
It's a fresh rebuild, 0.030 over, then sat 20 years and rusted one open cylinder that needs to be rehoned. Motor was not torque plate honed, so to do that this time ALL the cylinders would have to be rehoned, which means at least 0.040 in all eight. And the one will need a sleeve.
Originally Posted by maj75
Are you trying to save a numbers matching block?
If not, then as a buyer, I’d rather have a new shortblock than an engine that’s been rebuilt a couple of times...
I am... it's the original numbers matching block in a one of one car (the "Corvette Powered Pontiac", see more here: https://tinyurl.com/ybktjwqe )
A new block isn't always the hot ticket. For some folks, seasoned blocks are more desirable than a new block anyway (excluding aftermarket blocks and so on). But it matters how much metal is left, I'm with you there. We'll have it sonic checked so I'll know in the end.
I had this issue with a 350 that was going into my ‘72 SS Nova. It was a ‘72 Corvette motor with the same specs as the original 350. I had two bad cylinders due to rust, just like you, but the rodent urine that caused mine ruined the 2 valves, valve seats and two cylinders. My machine shop guy had another 350 4 bolt block and we used that one, .30 over.
I would have a hard time buying a car or an engine that had a sleeve in it if I knew it. No telling how the remainder of the block is in an unknown engine. As someone says, I would purchase a new GM block from summit and be done. Yes, it is likely a bit more, but it is a dramatically cleaner build.
If you plan to drive the car then I would replace the block.
If you plan to build it for sale and it truly is a one of a kind Pontiac/Corvette, then maybe do what you need to do to repair the block.
Another option may be to drop in a create motor and keep the complete original stored in case you do sell in the future and give it to the buyer with the choice to do what he would like with it.
May be a naive question... if a sleeve is done properly, what's the risk? Do they often become a problem?
Not always, but it can be a sign of further block problems. My 454 had a single sleeved cylinder and I was told it was fine. Upon magnafluxing I found 4 more cylinders that cracked.
The block was trashed.
Not always, but it can be a sign of further block problems. My 454 had a single sleeved cylinder and I was told it was fine. Upon magnafluxing I found 4 more cylinders that cracked.
The block was trashed.
Maybe not buy a block which had been sleeved without having it checked. If I had a block which needed a sleeve, had it magnafluxed, should be okay? Understand a future buyer may be skeptical. May need to supply some documentation from the machine shop...
Nothing wrong with a well done sleeve. I had all 8 cylinders sleeved in the 393 stroker Cleveland in my f250, the sleeves are tougher/wear better than the original block.
The rusty hole will need a sleeve, but the weird thing is, IT ALREADY HAD ONE. It appears the the block developed a small crack at some point and they put in a thin sleeve on this hole.
I can't tell if that was before or after they went 0.030 over, but maybe that sleeve is so thin BECAUSE it's been overbored already? It sure looks thin though.
Anyway, the plan is re-sleeve that one hole with a better sleeve, bore everything 0.040 over with torque plates, new pistons, balance, line hone.
Thanks for tall the input! 72% said Sleeve and that's the plan.
Plus - years back a friend had a bad *** 68 Camaro. Had a screaming 302 built by a high end local race shop. Everybody was amazed how awesome it ran. So, my Brother ended up buying it. When it eventually needed a rear seal he tore it down. On inspection it was all bs - a 350, cast crank, cast piston motor with 2 sleeves.
Well, it's back from the shop and it's sleeved in the one hole and it turned out nice. They used a MUCH thicker sleeve than whatever was in there before. Sure fortunately that the damage it encountered happened to be in the hole that was already sleeved anyway! Also note this motor had a lifter bore sleeved from the factory, which I've heard of but not actually seen before.
I have never heard of a lifter bore sleeved at the factory. GM would have tossed the block.
I don't know how many motors you've looked inside, but I've seen lots of block repairs right from the factory. No way GM tosses an entire good casting for a small defect like that. Common? No. Rare? Not really.
Now that said, I've never seen anything like that on a modern LS motor. Or any aluminum motor, actually. So they may have changed over the years.
I don't know how many motors you've looked inside, but I've seen lots of block repairs right from the factory. No way GM tosses an entire good casting for a small defect like that. Common? No. Rare? Not really.
Now that said, I've never seen anything like that on a modern LS motor. Or any aluminum motor, actually. So they may have changed over the years.
there is no way that GM would take the time to sleeve a lifter bore in the block as they would not even have a setup to do it. since the block had a cylinder sleeve i would guess there was a internal problem some time in the engine life.
I remember when the automotive industry was geared around the concept that items were repaired. In the late 70's or early 80's the concept changed and it became common to remove and replace complete components because the thought was it was cheaper to swap a major component even a complete motor than to disassemble it, sleeve a bore, install a new piston and reassemble it.
Back then I can imagine auto manufactures taking the time to repair a defected block over tossing it as they would today.
Today when you purchase one of the nice create motors everyone thinks are the best thing since a Subway sandwich, look closely at the detailed list of components, or talk to their tech support and you will learn that most of them are using reconditioned blocks and not new.
That's some input from someone who has been around since sliced bread was really something.
Last edited by OldCarBum; Mar 31, 2018 at 11:55 AM.
