Engine: Random pistons

[feralcat0_0]

mmagic just mentioned in his post that he had random sizes of pistons in his engine. Emagine my surprise when I removed my pistons today and found .25-.30-.& .40 pistons. Why would someone do such a CASCO thing? First ones I found were .25 so Thought all would be the same, strange as they are. Wouldn't The machine set up for one or two pistons being bored be the same to do the complete engine?
Also found one broken ring. What would cause a ring to break?
Guess I'll now have to bore the whole thing. Should I go all the way to .60?

[kmac530]

Remember these cars were not always collector cars....at some point they were NEW cars, then they were USED cars, then sometimes they were just OLD cars....now they are COLLECTOR cars. Some kid on a budget using one of these as his first driver might cut every corner possible to keep it running. May not have bored them all at the same time...repairs over the years.

As to bore size, you have 2 options, you could go to 0.60" and know you are fine, or, you could have the cylinders that are at 0.40 checked and measured and then bore the others to 0.40 if the ones already at 0.40 check out good.

[laughinlark]

You have a factory assembled engine. The pistons were selectively fitted according to bore size for the closest fit. Take your block to the machine shop and have them measure the bores.


Gordon S

[(S)]

Studebaker carefully measured every piston and the numbers you see are oversized to the stock size, but not .025 or .030.

These numbers mean + .0025 or +.00025 I forget which, it is in the manuals somewhere !!