Join Date: Sep 2006
Location: Eureka, Wisconsin
Re: Pilot Bearing for 390
Stop the sale here. The dimensions of a SKF 6204 are as follows:
47mm OD, 20mm ID, 14mm width.
That converts to 1.85" OD, .7874" ID, .551" wide.
JimNolan says he needs 1.85" OD to fit the hole in the crank. But he says his shaft size is .669".
That gives .1184" clearance from the bearing ID to his shaft. That is WAY TOO MUCH. A bearing with a 17mm ID would work out to .6693". That would make it a bitch getting the transmission in and out, but would be a proper fit to the input shaft. You DO NOT want the inner bearing race spinning loosely on the input shaft of your tranny. It is much harder steel than the shaft and could gall it up. That is why I run a bronze bushing rather than a bearing. The bushing will not last as long, but if you were to experience a catastrophic bearing failure it would ruin the input shaft of your trans.
If you cannot come up with a bushing let me know. I have an old worn out bushing from my 390 that had a .500" hole. I could throw it the lathe and open the hole up to fit your bigger pilot for your TKO.
BTW, the pilot bushing vs. pilot bearing arguement is older than the hills, but I prefer the bushing for the reasons I've mentioned.
Last edited by Dave66Galaxie; 08-30-2010 at 08:50 PM.