So I bought a 1950 8BA that was free but needed to be rebuilt. This past week I took it apart and had the block and heads tanked for cleaning and check for cracks. Everything checked out ok, no cracks but I had the shop use a dial bore guage and check my cylinders dimensions. I found out the motor had been bored .030" over and the cylinders were on average .007 - .009" over that. The shop told me .006" is the max before needing to be bored again. I was hoping to ridge ream and light hone and put .030" rings back on the pistons I have, but now I don't think that is a good idea. Will I get piston slap if I don't bore out to .060" over and get new pistons and rings. I am looking for some input on the situation???? .060" over to much????
If you are not planing on 10k a year it will ring no problem. .060 ain't even starting to bore one of those 95% will bore .187. Just make sure your new ring set has for one of the oil rings the modern 3 piece style ,U shaped center section and 2 thin rails.
Did they check for cylinder taper or S pattern wear? What do the thrust faces of the pistons look like? Flatman
The cylinders do taper out from .005-.006 to .008-.009" bottom to top of cylinder. The pistons have some decent wear but I didn't notice an s-pattern. I should look closer. Can you explain the s-pattern a little?
With 100K on a rebuild - how many more times you plan on rebuilding it? +.125" over is just getting started on a flatty...
Bore it to 3-5/16" if you have to rebuild it again you can go to 3-3/8". Like Flat Ernie said "how many more times are you going to rebuild it?"
I meant an S pattern wear in the cylinders. The cylinder will wear on one side at the bottom and the opposite side at the top. Exaggerated, the wear pattern resembles an S curve. Flatman