Author Topic: Engine builders.... pinion bearing advice needed (Evo)  (Read 1161 times)

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Offline choseneasy

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Engine builders.... pinion bearing advice needed (Evo)
« on: Saturday, September 03, 2011. 02:15:29 PM. »
What clearance are you guys happy with on the pinion/crank case bearing. My notes say .0006 to .0008 is a good spec. I guess my dilema is the fact the S&S books seem to shoot for .0001 to .0005.
  My plan is to use a "red" bearing (.2505" rollers--according to S&S).
(Crankcase I.D.) 1.7517-1.250 (pinion shaft)= .5017 clearance.

 The red roller x2 will give me .5010 to give me a total of .0007" clearance.
      If that seems too  loose my other option is to go to old style cages and bearings(.0006+) to get my clearance down to 5 tenths.

Don't want to lapp the case again as the shop gave me rollers that ranged from .0004 to .0008+ for proper sizing.  :banghead:
  Thanks in advance.
 

Offline Ultrashovel

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Re: Engine builders.... pinion bearing advice needed (Evo)
« Reply #1 on: Saturday, September 03, 2011. 03:34:18 PM. »
I looked in my Shovelhead book and it calls out .0004 to .0008. I don't have my Evo book handy but I think it was the same. Sounds good to me.

Offline choseneasy

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Re: Engine builders.... pinion bearing advice needed (Evo)
« Reply #2 on: Saturday, September 03, 2011. 04:45:52 PM. »
Evo book is .0002 to .0009 . I guess what I am really questioning is the fact that the S&S pinion fitment charts seem to indicate .0001 to .0005 clearance.
  Thanks for the reply Ultrashovel.

Offline wfolarry

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Re: Engine builders.... pinion bearing advice needed (Evo)
« Reply #3 on: Saturday, September 03, 2011. 04:52:24 PM. »
If the race is perfectly round you can run it on the tighter side of the spec. If it's not then the looser side is best. The easy way to check is go up in size until you get one that doesn't fit. The last one that fit is the right one.
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Offline Ultrashovel

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Re: Engine builders.... pinion bearing advice needed (Evo)
« Reply #4 on: Saturday, September 03, 2011. 04:57:27 PM. »
Evo book is .0002 to .0009 . I guess what I am really questioning is the fact that the S&S pinion fitment charts seem to indicate .0001 to .0005 clearance.
  Thanks for the reply Ultrashovel.

.0001 seems too tight, considering that cranks aren't all that close.....I'd do the .0004 +


Offline choseneasy

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Re: Engine builders.... pinion bearing advice needed (Evo)
« Reply #5 on: Saturday, September 03, 2011. 06:26:46 PM. »
Wfolarry, that is a good tip---red is the last of the oversize so can't try the next bigger. The bore is a tenth off on a few places., I think I will run with 7 tenths.
      Thanks again!!!