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Just getting ready to take the block and crank to machine shop this week so I was gathering up parts today. Looking everything over I found that one of the piston skirts is cracked and it actually broke off. GD...

So my ideas of reusing the pistons just got shot up. Maybe I'll find that the block has to be punched over and I'd need replacements anyway. Regardless just another setback and can of worms I didn't want to open.

Summit Racing has OE replacements as well as Keith Black for under $150/set in standard bore, or maybe I'll just have the machine shop buy/install them.

Guess better now than when its all back together. Ugh....
 

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before you buy pistons, see what the machine shop says is needed to make the cylinder round again. it wouldnt do to buy a set of .030 pistons only to find you needed .040 instead.
 

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before you buy pistons, see what the machine shop says is needed to make the cylinder round again. it wouldnt do to buy a set of .030 pistons only to find you needed .040 instead.
+1

........ or buy 0.030's when the block can be cleanly finished out at 0.020". Many make the mistake of going automatically to 0.030" from a std. bore, when actually 0.020" pistons are readily available. No good reason to give away engine block metal, and the chance to have another overhaul out of the same block after you've put a couple of hundred thousand miles on it.


Z
 

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If the piston was cracked then it was likely scrapping hard on the cylinder wall on one side of the crack - likely you'll need to bore the block substantially to get the cylinder back to round. I had to go 60 thousands on mine. (That was way back in 1986 or so - it has been working great ever since.)
 

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These days pistons can be made at ANY oversize as long as there is a complementing ring set available. .001, .002,.003 or .031,.032 it doesn't matter. There is at least one piston company that makes forged parts that will do that at no additional charge! A properly rebult engine should NOT need a rebuild as long sd you won the car. We don't put 100,000 miles on a classic car any more. No reason to be worried about "future rebuilds" on a 50+ year old car..
Randy
 

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"............. A properly rebult engine should NOT need a rebuild as long sd you won the car. We don't put 100,000 miles on a classic car any more. No reason to be worried about "future rebuilds" on a 50+ year old car..
Randy

Granted, most people don't drive the wheels off anymore.

But there is still a vocal minority who can hit the 100,000 mile mark in their classic in well under 10 years. And thank god for them. Nothing keeps general interest up like seeing a classic car on the road every day.


Z
 

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We don't put 100,000 miles on a classic car any more. No reason to be worried about "future rebuilds" on a 50+ year old car..
Randy
Speak for yourself, Randy... :surprise:

'67 Fastback Daily Driver - Over 100,000 miles since purchased by me 12 years ago. :yoho: And likely getting to be time for a rebuild...
 

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If the piston was cracked then it was likely scrapping hard on the cylinder wall on one side of the crack - likely you'll need to bore the block substantially to get the cylinder back to round. I had to go 60 thousands on mine. (That was way back in 1986 or so - it has been working great ever since.)

You never know. I rebuilt a '69 351W and all the factory pistons had cracked skirts. One piston skirt was completely broken off. There was a groove in that cylinder, but a .030 bore took care of it. Likely, the OP's block required a bore and new pistons anyway. That is, if he wanted to do it right. I've seen people use a ridge reamer to scrape of the ridge at the tops of the cylinders and slap the old pistons back in with new rings. Not surprisingly, these engines had some serious piston slap and didn't last long before they were blowing smoke.
 

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These days pistons can be made at ANY oversize as long as there is a complementing ring set available. .001, .002,.003 or .031,.032 it doesn't matter. There is at least one piston company that makes forged parts that will do that at no additional charge! A properly rebult engine should NOT need a rebuild as long sd you won the car. We don't put 100,000 miles on a classic car any more. No reason to be worried about "future rebuilds" on a 50+ year old car..
Randy
actually if you think about it, you dont have to make rings in anything other than certain standard sizes and over sizes. for instance, its true you can get pistons in just about any over size you might need. lets say you need a .020 over size, but they dont make a ring package in that over size. not a big deal, you just buy a set of .030 over sizes rings, and then file to fit the cylinders using a tool like this one;

https://www.summitracing.com/parts/pro-66785

that way you get the exact ring gap you want, though you will have to spend some time doing it.
 

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Well my apologies to those of you who put 10,000+ miles a year on your cars. I applaud you. "Many" classics have been relegated to ''sunny day" or "weekend" cars rather than daily drivers. Even so , advances in piston ring technology and piston skirt designs have resulted in far less bore wear than in the early days. For example a late 90's 5.0 EFI engine can go 200,000 miles and still pass a California smog test.

rbohm,
You are correct on the ring information . From standard 4.000 you can get +.005,.010,.015,.020,.025,.030,.035,.040,.045,.050,.060,.063,.065,.070,.080. Certainly a larger bore set (+.005) can be file fit to a specific bore and is done all the time. With this availability there is no reason to "got to .030" automatically.
Randy
 
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