Finding a 90K mile 235 without a noticeable amount of cylinder taper is sort of like finding a chicken with lips- - - -it's not likely to happen. If there's more than .005" of taper in the cylinders, a re-ring job will be a very short-lived fix. Rings must expand and contract constantly to maintain contact with a bore that's not perfectly straight, and at 2,000 RPM that flexing is happening 66 times a second. Once the cylinders are rebored and new oversize pistons are fitted, the ring flex goes away because the cylinders are straight again. Another advantage is that the replacement pistons will be aluminum, and the lighter piston weight means less pounding on the Babbit rod bearings. The original pistons were cast iron.
Another option would be to find a later model 235 in running shape, drop it in temporarily, and make the original engine a long term rebuilding project. There's nothing wrong with Babbit-pounder engines- - - -as long as they're built up properly and the connecting rod oil clearance is kept to a minimum by adjusting the shim pack periodically. Jerry
Thanks for the reply! Do you know of any places that could re-build the original babbitt bearings? Like I said, I know of none.
