using kent moore tool with aftermarket gears

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using kent moore tool with aftermarket gears

Post by bluezr2 » Fri Apr 04, 2008 1:25 pm

I have been using some kent moore pinion depth tools (23597 set and 21777 set) to set up some General Motors 10 and 12 bolt rear ends with factory gear sets. The factory gear sets are marked with a + or - pinion depth measurement that references a "nominal" pinion depth. I have had no problems so far. My problem is that I went to start installing a set of aftermarket gears in a 79 olds 98 with 8.5" 10 bolt, but the aftermarket gears are marked with an actual pinion depth measurement with no reference to the "nominal" depth that General Motors and kent moore use. I tried a "universal" pinion depth tool with a dial indicator and that new pinion depth tool that ratech makes, but they aren't as consistant as the kent moore sets. Do you know of a way to use the kent moore pinion depth tools to install a set of aftermarket gears? Do you know if there is a chart with a list of General Motors "nominal" pinion depths that I could use to do some math?

Thanks, George

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Re: using kent moore tool with aftermarket gears

Post by monzaz » Sun Apr 27, 2008 9:22 am

George, To tell you the truth I am not totally familiar with the kent Morre set-up .

With the inconsistant ring and pinion castings and forgings the specific addition and subtraction using such depth style tools really does not hold well even if you use the GM to GM gears etc. We will always Always use the pattern to set up a gear. We use set-up bearings and will normally reference old shims from the housing pinion shaft. We get our reference pattern with the stock shim then read the pattern and reset if needed form the reference pattern on how much shim to add or subtract. Then when we have our pattern correct we will measure the thickness difference between the to bearings and re adjust the shim pack accordingly IF needed. If you use GOOD bearing kits this is usually never needed... But even the best of everything on parts, we are human and flaws and defective parts do get through.

The Pinion depth tools will get you close BUT never fail to use the physical gear pattern with marking compound to tell you that the gear is in the correct location. Sometime the old fashion ways are the best and you might have more labor invovled ...BUT I guarentee the extra time spent will more than make up for a strong quiet well set-up gear set. Jim Mitschke
J D Race

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