Vincent,
basically you may be right, I cannot specify exact tempertures for hot glueing bearings in an alu case as no oversize is known. Also you don´t know how fast the Loctite cures while the bearing outer heats up in the hot case. I can definitely say cold fitting a bearing in an alu case is useless, tried it on the gearbox input bearing behind the clutch : After loctiting cold and heating it to operating temperature of around 80 degrees I had NO problem to knock it out with plastic hammer. Did same procedure at 100 degrees dropping in the bearing quick and later at same temperature it was very OK. There is a minor uncertainty about what amount of preload you´d get on the hot glued bearing at what chosen temperature so you better do a test before and feel. If you don´t like the feel of being too tight at working temperature you just heat the case to above 150 degrees and it will definitely be easy to knock out for next try at lower fitting temperature. Certainly it is safer to machine an adapter bush for exact shrink fits but this is often overkill when only a bit of oversize is to fix. Bad alignment of bearings would not be a matter with little wear in bores.
And NO, STAKING is CRAP !! It is a disgrace to any designer of machinery to try get him out of troubles with this bodge. Nor would I ever dare to tap the circumference of the main bearing seats as this will end in disaster for this highly loaded place !
I went for lipped outer roller races - no staking - and no big oversize bushes in the engine because I went all metric for sure , including all crankshaft sizes except for the oil pump worm and timing gear plus the ESA items. So when chosing a modern roller bearing you can get the 30x62x20 or x16 sizes and suitable lips on inner or outer races to your liking and assembling strategies and so no oversize boring in engine case is due , just licking up any wear from 63,5 mm imperial to install a reduction to 62 mm. The modern polyamid glas reinforced caged bearins are way higher load specified than the old all metal type, even when having all over smaller dimensions. The 1 " crank mainshaft can be bushed to 30 mm in no time to get to sizes then. Well, all depends on lots of factors , no easy out for all cases . . . .
Vic
basically you may be right, I cannot specify exact tempertures for hot glueing bearings in an alu case as no oversize is known. Also you don´t know how fast the Loctite cures while the bearing outer heats up in the hot case. I can definitely say cold fitting a bearing in an alu case is useless, tried it on the gearbox input bearing behind the clutch : After loctiting cold and heating it to operating temperature of around 80 degrees I had NO problem to knock it out with plastic hammer. Did same procedure at 100 degrees dropping in the bearing quick and later at same temperature it was very OK. There is a minor uncertainty about what amount of preload you´d get on the hot glued bearing at what chosen temperature so you better do a test before and feel. If you don´t like the feel of being too tight at working temperature you just heat the case to above 150 degrees and it will definitely be easy to knock out for next try at lower fitting temperature. Certainly it is safer to machine an adapter bush for exact shrink fits but this is often overkill when only a bit of oversize is to fix. Bad alignment of bearings would not be a matter with little wear in bores.
And NO, STAKING is CRAP !! It is a disgrace to any designer of machinery to try get him out of troubles with this bodge. Nor would I ever dare to tap the circumference of the main bearing seats as this will end in disaster for this highly loaded place !
I went for lipped outer roller races - no staking - and no big oversize bushes in the engine because I went all metric for sure , including all crankshaft sizes except for the oil pump worm and timing gear plus the ESA items. So when chosing a modern roller bearing you can get the 30x62x20 or x16 sizes and suitable lips on inner or outer races to your liking and assembling strategies and so no oversize boring in engine case is due , just licking up any wear from 63,5 mm imperial to install a reduction to 62 mm. The modern polyamid glas reinforced caged bearins are way higher load specified than the old all metal type, even when having all over smaller dimensions. The 1 " crank mainshaft can be bushed to 30 mm in no time to get to sizes then. Well, all depends on lots of factors , no easy out for all cases . . . .
Vic
