At 02:04 PM 10/26/00 -0700, you wrote:
> Dear list,
>I have finally aquired (thanks Herb for the help) the 2:88 gears and carrier
>I need for my "Econo Tiger". I want to "guesstimate" the pinion depth
>setting (on the off chance I get it right the first time). The original
>pinion had a +11 (eleven) marking. The Tiger manual makes mention of plus
>or minus 1,2,3 as an example. Is it common to find a plus eleven pinion OR
>did the guy who engraved the number tip one too many the night before and
>mark this pinion twice? Anyway, I was just going to compensate the
>difference with the shims (I put the old shims in a marked envelope since
>I'm not the stupid kid I used to be). By the way the "new" pinion is a -1(if
>that means anything in assisting me).
The factory grouped the housings and gears by tolerance groups to
reduce the time required to "fit" the setups. This is the reason for the
plus and minus or high and low designations. The markings applied were
referenced to the perfect 0 - 0 design standard. They were also marked in
reference to the pattern produced on the ring gear, not by measured
dimension, as machined. The pinion depth is measured from the centerline
if the axles to the ground flat on the end of the pinion. The plus or
minus is a reference to the 2.650" (this is a number from memory - check
it) zero standard. You need a special tool to make this measurement. All
the bearings also have tolerance and the resultant "assembly" is what you
have to measure. Simply taking what was, calculating the difference, and
adding or subtracting shims may not even get you into the ballpark without
measurement.
Used gears have already been "broken - in" to a particular wear
pattern. Resetting these gears in a different housing, frequently results
in a noisy operation. As long as the pattern is within the allowable
tolerance the gears will function without problem even though they make a
lot of noise. Getting back to the OEM pattern is very difficult, but it
has been done.
The quickest way to set the carrier is to have a set of carrier
bearings that have modified ID's to avoid the press fit operation. They
simply slip onto the carrier stubs. This way you can get the proper setups
without having to "pull" the bearings to make a change. After you have a
workable pattern, you can spread the case and add equal shims to each side
to obtain preload. All if this is an iterative process and you must have
the pinion in the proper position to make any headway. The pattern is best
measured with a compound of "white lead" This may be very difficult to
find and blueing will work, but will take much longer to develop an
observable pattern. The ring gear - carrier assembly should also be
preloaded to resist rotation while turning the pinion to get enough
pressure to develop the pattern. I use wedge shaped block of wood driven
between the case and the ring gear.
I wish you luck in this endeavor.
Tom Hall
|