The Stovebolt Site Forums The Shop Area Engine Shop need advise from builders of 235s

Ok here is what I've got so far on my 56 235 bored .030 with new pistons. As the manual states to test fit the pistons to cylinders by inverting, sliding half way up the piston pin with a .0015 feeler gauge, pulling it out with a fish scale, looking for a 7 to 18 lb pull. As my previous post stated (an thanks to those who replied prompting me to further test) a .0015 gauge has 1 lb resistance. Increasing the size of the gauge to .0020=3 lbs, .0025 = 5 lb pull and .0030 could not fit the piston in the bore.

What do you think? Is this too out of spec? Should it be machined again?

Rick.........

I think whomever did the bore/hone job knew exactly what he was doing, and did it precisely right. Feeler gauges and spring scales are stone age technology. Your machine shop probably used a dial bore gauge and bored/honed the block to exactly the specifications the piston manufacturer provided. When a dial bore gauge can measure clerarance down to a fraction of a thousandth, repeatedly, with no "fish scale" guesswork, it doesn't get any better than that.


Doing the measurement with a feeler gauge and a spring scale sort of reminds me of the saying, "Measure it with a micrometer, mark it with chalk, and cut it off with an axe!" When the family shop started using a precision power hone instead of a reamer to fit wrist pin bushings and a dial bore gauge to measure clearance back in the early 1950's, our customers accused us of fitting them too loose. The fix was to tap the small end of the rod with a hammer to egg-shape it a little so they would have a bit of difficulty installing the wrist pins. As soon as the engine warmed up a couple of times, the bushing would get round again, and our customers who were too ignorant to appreciate good machine work were happy as a pig in slop!
Jerry

Oh, man, is that funny Jerry!