[My442]

Originally Posted by rexs73gto

I was out in the garage the other day & remembered that there was some one wanting the part number for the cheap pilot bearing that came from Tractor supply. It was back in the bearing section & I found the bearing that looked the same & came back later to make sure it was the same size. The only difference is that this one has a seal on both sides instead of just one side as the correct number from any parts store would have. It's an SKF Br7109, I paid just under $ 6.00 including tax for this one & have put these now in about 5 different engines in the last few years with no problems & a lot less cost. At just under $ 6.00 you can buy 4 for the price of one from your local Autozone or Advance parts store. Plus there made in the USA.

That bearing is about $25 everywhere I looked.

[rexs73gto]

The one I bought & have bought at Tractor Supply was just under $ 6.00 . If you want I can get you one & send it to you if you want . Just pay me for the bearing & the ride & you'll be all set. Depending on where your at it shouldn't cost more then about $ 3.00 to send.

[blykins]

What I base the usage on is the clutch disc material. If it's a regular organic disc, a bushing is probably the best choice. When you get into the more exotic disc materials, such as sintered iron, Kevlar, etc., then the dust can be abrasive to a bronze bushing and it will wear it quicker. In those instances, it's best to use a bearing.

[421-6speed]

Originally Posted by tom s

This another one of those deals I must be a lucky pontiac owner.I have driven and built pontiac engines since 1962.Virtually all have been stick shift cars.I have used both bushings and bearings with no failures.I have NEVER checked alignment on one of them.What I do when installing a clutch assm is use a old input shaft from a trans.I never use the plastic ones that come with clutch kits.I have used factory bells,Mcleod and most other EXCEPT a Lakewood.Trans from T-10s,ST-10s,muncies,saginaws and Tremics and even rope shaft 62-63 tempests.Carry on.Tom

Its funny you mention this Tom, I just went through this on my 1960 Ventura. There are only two choices for bell housings for this application, factory or period scatter shield. I am using the factory bell so I figured I would check alignment using a dial indicator, it was only out by .002, I also used the Dorman bushing 690-023. Goes to show the factory bells where pretty close...

[Doug]

In a recent topic in the 61-63 Tempest & LeMans TECH forum which touched on pilot shaft bearings/bushings, I posted this information from the 1963 TEMPEST CHASSIS SHOP MANUAL, on page 6D-6 paragraph 8, which reads, in part:

“…..If bearing is loose, remove from crankshaft and inspect bore for wear. If bearing has been run loose in crankshaft for some time, a noticeable ridge will be found in counterbore. If diameter of bore is more than .005" oversize (spec. 1.379" ), the crankshaft must be replaced…..”

I don’t have access to Chassis Shop Manuals for other models of Pontiacs but I suspect that other manuals list similar information, particularly the specification that the bearing/bushing counterbore diameter is 1.379”.

Some research of Internet advertisements I have done indicates:

Pilot bearing # 7109 (GM part number 15533265)
•Size is 1.3780"OD x 0.5906"ID x 0.3543"W (35 mm OD x 15 mm ID x 9 mm W)

•Pilot bearing # 6202
• Size is 1.3780"OD x 0.5906"ID x 0.4331"W (35 mm OD x 15 mm ID x 11 mm W)
# 6202 bearing may be used, but the crank opening may need to be machined 2 mm deeper

The Dorman 690-023 pilot bushing piece lists:
O.D. 1.381"
I.D. 0.592"
Width 0.363" (I have also seen an Ebay listing for the part listing at 0.437 width?)

I note that the diameters of the bearing(s) is 1.378” when the factory spec for the counterbore is 1.379” (indicating a 0.001” clearance fit for the 1.378” bearings).

I would note however that the diameter of the bushing is 1.381”, when the factory spec for the counterbore is 1.379” (indicating a 0.002” interference fit for the 1.381” bushing).
Indeed, in many instances, people have had to “machine down” the bushing to make it fit.
(I think that perhaps some have also had to work on some bearings to make them fit.)

Obviously, the factory anticipated that the counterbores would wear (enlarge) and they “accepted” a 0.005” limit. Accordingly, it occurs to me that in an instance where the counterbore wear is approaching 0.005”, then the use of a bushing at 1.381” would be an acceptable counterbore fit, allowing for continued use of the crankshaft rather than discarding it (or doing substantial repair).

The bearings have an internal diameter of 0.5906” whereas the bushing is at 0.592”ID, suggesting that the bearing is a 0.0014“ tighter fit for the pilot shaft than the bushing, thereby better “stabilizing“ the pilot shaft (albeit by a very small amount).

I measured my Muncie transmission’s pilot shaft diameter to be 0.564”. It shows no evidence of wear. This indicates that the shaft has a 0.0266” clearance to a bearing and a 0.0280” clearance to a bushing.

The transmission is a freshly rebuilt unit with a new input shaft bearing. From the front mating surface of the transmission to the end of the pilot shaft portion, the total overall length of the input shaft is about 6 ½” with about 3” of it running thru the input shaft collar and with about 2” of shaft splining exposed. When I move the pilot shaft end up and down with slight force, the end moves a total of about 0.030“ up and down.

The transmission has no readily evidenced signs of input shaft splining wear. My new Centerforce clutch disc has about 1 5/16” of splining. With the disc on the input shaft splining, when I move the edge of the disc with slight force front-to-back, the perimeter of the disc moves a total about 3/32” front-to-back.

Of course, manufacturing and machining tolerances come into play in all of this, AND, when comparing fitments based on diameter dimensions, etc., the actual deviation (FROM A CENTERLINE) in any direction is only one-half the difference of the measurements.

[421-6speed]

My crank bore measurement is 1.376 while both of the Dorman bushings I have measure 1.380. I had no issues installing the bushing.

[rexs73gto]

The pilot bearings I have have an inside of .5906, an outside of 1.378 & the width is .3543. These fit in the back of the crank with a little bit of a tight fit to them & have to be hammered in, ( not really hammered) & the inner is tight on my M-22 as if I don't have it lined up perfect it takes a few times to get the trans to line up & put in.