Re post for max bore for a sleeve.

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Wally-T

Wally-T

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Ok folks. Thanks for all the replies!
But I should have given more info, it seems, lol.
The engine came out of an early 80's D150 that I bought to do some upgrades to my 63 Savoy. It hadn't run for years, and was still in the truck until about a week before I bought it, so I decided to start it on the floor before I installed it. Well, it ran soooo good that I did a little jig haha. Smooth idle, and just a little bit of black smoke from me pouring far too much fuel down the carb to get it started. So I decided that it deserved a new head and pan gasket before I stab it into the car. Imagine my surprise when I found a 1/4 inch wide groove running all the way down one bore that's about 4 thou deep, and no crazy oil smoke! Rats I say!!! Anyway, the other bores are totally acceptable (to me, anyway, lol.)' and so I'm just going to ball hone them and re ring the old pistons. If the crank is good, I'll just give it a little spit and polish, and some new bearings.
So if I,m going to sleeve the one bore, and I am, would I be better off with the thicker sleeve, or the thinner one? I could have made a long story short (like my first post), but I rather enjoyed this :lol: Thanks folks.
Wally.
 
These are questions you need to ask your machine shop as they can see the engine right in front of them and give you a much more accurate answer.
 
RustyRatRod said:
These are questions you need to ask your machine shop as they can see the engine right in front of them and give you a much more accurate answer.
Click to expand...
I don't suppose these young fellers have ever seen a slant, but I suppose they're the same as any other block they've bored. I'll have to cart it over there. Thanks.
 
Wally-T said:
Ok folks. Thanks for all the replies!
But I should have given more info, it seems, lol.
The engine came out of an early 80's D150 that I bought to do some upgrades to my 63 Savoy. It hadn't run for years, and was still in the truck until about a week before I bought it, so I decided to start it on the floor before I installed it. Well, it ran soooo good that I did a little jig haha. Smooth idle, and just a little bit of black smoke from me pouring far too much fuel down the carb to get it started. So I decided that it deserved a new head and pan gasket before I stab it into the car. Imagine my surprise when I found a 1/4 inch wide groove running all the way down one bore that's about 4 thou deep, and no crazy oil smoke! Rats I say!!! Anyway, the other bores are totally acceptable (to me, anyway, lol.)' and so I'm just going to ball hone them and re ring the old pistons. If the crank is good, I'll just give it a little spit and polish, and some new bearings.
So if I,m going to sleeve the one bore, and I am, would I be better off with the thicker sleeve, or the thinner one? I could have made a long story short (like my first post), but I rather enjoyed this :lol: Thanks folks.
Wally.
Click to expand...
Why are You feeling compelled to sleeve a cylinder over a .004" deep gouge? I'm more curious as to the cause of this damage, 1st, ..........broken/siezed ring, incorrect(or damaged)oil ring, debris, piston skirt cracked.????
 
I can tell you this. I've sonic tested a few I have here. The thinnest spot on those was about .371" on a non thrust side. That's unbelievably thick. That would take a .100" overbore and not even feel it. That doesn't mean they're all that thick. But you don't go after power with boring anyway. It doesn't make as big a difference as adding stroke. The slant 6 already has about as much stroke as the crank case can stand, though.
 
RustyRatRod said:
I can tell you this. I've sonic tested a few I have here. The thinnest spot on those was about .371" on a non thrust side. That's unbelievably thick. That would take a .100" overbore and not even feel it. That doesn't mean they're all that thick. But you don't go after power with boring anyway. It doesn't make as big a difference as adding stroke. The slant 6 already has about as much stroke as the crank case can stand, though.
Click to expand...
True, the real power in the overbore is getting valve space, the displacement is secondary unless You're gaining real cubes. I did work out how to get 273c.i. on paper, but that's an entire thread if it's own,....here it seems this is just a 're-ring & go'.
 
Wally-T said:
The engine came out of an early 80's D150
Click to expand...

Those '80s units had been lightened/cheapened several times versus the first cast-crank blocks which started in mid-'76, which in turn were lightened/cheapened versus the previous forged-crank motors.

Every block is different, but an '80s block would not be my choice if I wanted to build a max-bore motor.
 
At 0.004 deep, I'd bore the one hole 0.010 over if there's a single piston available in that size.
 
slantsixdan said:
Those '80s units had been lightened/cheapened several times versus the first cast-crank blocks which started in mid-'76, which in turn were lightened/cheapened versus the previous forged-crank motors.

Every block is different, but an '80s block would not be my choice if I wanted to build a max-bore motor.
Click to expand...
Which is why I always stress sonic testing. You just don't know till you see it.
 

As far as I know 0.020 is the smallest overbore for which matching pistons and rings are available.
I remember hearing from the old (no longer there) machine shop where they would complain about people who wanted to bore 1 hole, or 3 holes in a V8 but not do them all. Or to machine 1 crank journal and not the rest to match
 
It is entirly possible to just bore one cyl and use an oversize piston. I have one of my race engines with three .030 pistons, and three .060 pistons. It runs fine. Just make sure the "oddball" piston has the same compression distance, and weight as the other pistons.
 
Wehen it comes to mismatched pistons, I once ran across a case where a "low mileage JDM" Toyota six cylinder had four dished pistons and two flat tops, or maybe it was the other way around. It ran fine, though. The owner only found out with a boroscope after investigating a problem that turned out not to be the engine at all.
 
As I said in another slant thread, I had one in a 17' Higgins Utility boat & was stuck when I bought, the head had froze. After oil soaking, I broke the rusted cylinder loose w/ sledge & 4x4, then sanded w/80 grit paper, vacuumed,oiled, wiped, repeated, ad nauseum.

Put junkyard head on it, started it & used it for slalom water skiiing for 2-3 years before selling it.

It never smoked & had good compression.
So I'd run it like it is without hesitation, unless wanting a Hi- Perf build .
 
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