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« on: February 10, 2024, 07:34:30 PM »
Some pics of what we go through to properly rebuild these. No more big end bearings existed for these engines that anyone knows about. Custom made bearings were the answer but complicating things is the 4-5HP Bamford used two different I D.s in the big end of the rod, early thick she'll bearings and late thin shell, both use the same 3.000 crank pin. Now, when all the possible I.Ds and undersizes are considered the number of stock bearings becomes quite large AND expensive. Also complicating things is there isn't a market for 1000s of bearings. The answer became having one size custom bearing made that would be as adaptable as possible. I had bearings made for the large rod bore and all of the them are 030" undersize. It's much cheaper to grind the cranks 030 under than to stock all sizes of bearings or than having them welded and ground to standard. Pictures show the current Z2 4.5HP project. Boring the big end on the mill, then it was honed to size and locking tabs machined. Also shown is the finished rod and the newly made inserts. Now off to the crank grinder to have the pin sized to my bearings.