Miloon Drive

71 Sebring + said

So are you thinking the bushing didn't get reamed to size and it was too tight of a fit causing premature failure of the bronze gear. After the fact my engine builder said he usually gets about 20,000 miles out of them. He did send me a new mellonized drive gear and set of lifters.

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The hole in the block goes out of round.

They make bushing that they claim don’t need to be sized but like I said, the hole in the block gets out of round and it also shrinks with heat cycles.

Plus, there is a tolerance for the size of the hole from the factory.

If you happen to have a block that stated out on the low side of the tolerance. Then the hole gets smaller and the bushing that is said to be “prefit” gets installed. It’s got enough clearance that it slides right in, but it’s too tight to get enough oil to keep it from grabbing the shaft.

And once it starts getting fatter the shaft it keeps wearing it.

I size every bushing I install. I’ve never had one that I could not feel the sizing broach not doing its job.