STD gen/alt panhead type case, pinion bearing spec?

[RICOCHET]

Taking some measurements for loose pinion bearings on this STD aftermarket Pan type case. Case came already line reamed and the race measures out at 1.752. Is that typical loosing .002 from line reaming new? In the Panhead manual it calls for .0004 - .0008 loose for pinion bearing on the spec page but refers to different terminology on the proceedure page "running fit". Is this one in the same and is that the correct spec to use in STD cases? Crank assembly is T & O later type with later pinion as in shovel. What is shovel pinion bearing to race tolerance or running tolerance? Shaft od measures exactly 1.2500. If I'm reading this all correctly this indicates a .0006 os or .0008 os bearing to achieve a .0008 or .0004 running tolerance. Any input is welcome and appreciated.

dICK

[steinauge]

I have always used .0005-.001 for a pinion bearing clearance spec.Take your shaft OD,subtract it from your race ID, subtract .001" from the result (or whatever number you want to use for clearance) divide by two and thats your roller size.Those case races are normally undersize and (theoretically)clean up to accept a standard bearing.In practice its whatever size roller gives you the correct clearance once the race has cleaned up.HTH

[RICOCHET]

Thanks,

So I'm still verifying the measurements having figured out the new measuring tools and they bear out within the specs already given. But I'm confused as to what bearing set to use in this STD right case. I see bearing sets that call for 28 pieces of what I believe are short rollers set 2 wide. I see mention of a 1/4 by .490 long bearings and then v-twin catalog refers to both the 28 piece set or using the 87 - 89 type set in earlier models. What's common practice on STD cases? The manual is useless for this detail. Not even part numbers.

Dick

[steinauge]

Given a choice I would use the 58-86 style bearing.This consists of 28 rollers(.250"std)2 cages and 2 washers.It is retained by a spiralock that fits in the groove in the pinion shaft.The reason I would use this bearing is that there are oversize rollers available for it that may be used in the existing cages when it gets to be overhaul time.The STD case will accept this bearing assy.The PNs are as follows; cages-43578-35(2) washers-24692-58(2) retaining ring-11007 (1) and whatever size rollers you need.HTH

[RICOCHET]

Thanks again. That's the path I was originally going down and have the cages, washers and lock already but then saw the reference to the later bearing. This motor is 120 inch, HP. Is one bearing set going to be more reliable under these circumstances. Seems the later setup puts more load bearing surface in there. I'll have to take a closer look at my cages to see how long of a bearing it'l hold.

Dick

[steinauge]

I couldnt really say.A lot of people use the late 92 and up style bearing and I believe it is a good bearing.I KNOW the early bearing is a good bearing and it is rebuildable.We ran some big strokers and even a fueler on that 58-86 pinion bearing and had no trouble.

[RICOCHET]

Turns out the bearing cages and set up I have is for the double row of .490 Long bearings so that puts the most amount of bearing surface in there of the choices. Using the plug fit method and some pin guages for accuracy puts my choices at .00034 or .00074 clearance using either the .0008 or .0006 OS bearings. With the manual stating to run at .0004 to .0008 clearance I think I'l get the .0006 OS bearings.

Dick