Distributor Gear fit

This question is about the distributor gear in my Windsor but figured the same should apply to 460's as well.

I have a question about clearance. The MSD distributor shaft I have measures 0.531" OD. Most of the dist. gears you see for sale state 0.530" or 0.531". The cast MSD gear I pressed off was 0.528" ID. The new Comp Cams composite gear (35100) I bought was 0.528" ID as well. This is the second time I have used the 35100 gear and the last one was the same ID. My question is, "how tight of fit is the gear supposed to be on the shaft?".  I called Comp Cams today and they said to drill out the gear so it would slide on the shaft. I always had the understanding the gear was supposed to be a slight interference fit on the shaft not just held in place by the roll pin. If it is supposed to slide on why doesn't MSD and Comp Cams just make the gear 0.531"?

jasonf wrote:This question is about the distributor gear in my Windsor but figured the same should apply to 460's as well.

I have a question about clearance. The MSD distributor shaft I have measures 0.531" OD. Most of the dist. gears you see for sale state 0.530" or 0.531". The cast MSD gear I pressed off was 0.528" ID. The new Comp Cams composite gear (35100) I bought was 0.528" ID as well. This is the second time I have used the 35100 gear and the last one was the same ID. My question is, "how tight of fit is the gear supposed to be on the shaft?".  I called Comp Cams today and they said to drill out the gear so it would slide on the shaft. I always had the understanding the gear was supposed to be a slight interference fit on the shaft not just held in place by the roll pin. If it is supposed to slide on why doesn't MSD and Comp Cams just make the gear 0.531"?

I always try for .001" press fit to the shaft.
With a composite gear, it needs to have very little press-fit however, NOT an on size, slip fit.

Bake the gear at a nice oven 350, dip shaft in liquid nitrogen. It'll slip fit as long as your quick..............

kim wrote:Bake  the gear at a nice oven 350, dip shaft in liquid nitrogen.  It'll slip fit as long as your quick..............  

A composite gear? It will probably look like cookie dough when it comes out of the oven.

Any ideas on how to hone 0.002" out of a distributor gear at home?

jasonf wrote:

kim wrote:Bake  the gear at a nice oven 350, dip shaft in liquid nitrogen.  It'll slip fit as long as your quick..............  

A composite gear? It will probably look like cookie dough when it comes out of the oven.

Shouldn't environment it lives in can get into the 200 range pretty even. But if concerned. A quicker cycle through some boiling water. Bout 100 degrees less heat...

kim wrote:

jasonf wrote:

kim wrote:Bake  the gear at a nice oven 350, dip shaft in liquid nitrogen.  It'll slip fit as long as your quick..............  

A composite gear? It will probably look like cookie dough when it comes out of the oven.

Shouldn't environment it lives in can get into the 200 range pretty even.  But if concerned.  A quicker cycle through some boiling water.  Bout 100 degrees less heat...

I was thinking boiled water maybe heat gun but when I asked the Comp Cams guy he acted like I was from another planet. I think it is funny how the cam people don't make distributors just the gear and the distributor people don't make cams that are compatible with their cam gears. MSD shows a distributor with a steel gear but it was not available till next month when I looked. It cost about the same as the regular dist plus the composite gear so go figure.