Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Hi Hurric,

The crank endfloat was controlled by the needle bearings. The bearings are positioned in the crankcase half prior to assy. to give the desired crank position and endfloat (the bearing cases contolling endfloat) then when the mating half of the crankcase is attached it holds everything in place.

You can do the same with your bushings, but as you say tightening the crankcase makes the crank bind then i would suspect the bores in the crankcase are either out of line slightly or just crushing the bush a little (bushes are much more sensitive to alignment etc. than needle bearings because of the closer tolerence).  Maybe put the bushes in the crankcase and tighten, then try to insert the crank into one bush at a time from the outside, if the crank fits and turns the issue is probably alignment.  Both problems can be fixed with a suitable reamer or you may be able to 'bed it in' with some moly grease and an electric drill to spin the crank.

Hope this helps and is not insuling your intellegence (no offence intended)

Ade