Fitting timing gears

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rgould1910
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Fitting timing gears

Post by rgould1910 » Sun Jul 28, 2019 1:30 pm

I've been a huge fan of Time Saver for years. Today I found another use. Timing gears. When I got a newly babbitted block back from the rebuilder and installed the crank and cam with the timing gears installed, it was was evident the gears were too close. They were binding a bit making marks on the large time gear. I tried a number of other timing gears I had, bronze, aluminum and fiber and all were too tight. I decided to lap the gears using
20190728_101247.jpg
green Time Saver on an aluminum large time gear and hardened steel small-time gear. The result was very good. There is no detectable play and the gears run against each other without binding. Because I used an aluminum large time gear, I could have used yellow Time Saver. However I wanted the compound to cut so I opted for the green. It turned out to be a good choice. Except for the fact that you need to be very careful and clean the gears thoroughly, removing every speck of the compound, I was very pleased with the outcome.[attachment=1]20190728_101247.jpg[/
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Scott_Conger
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Re: Fitting timing gears

Post by Scott_Conger » Sun Jul 28, 2019 3:55 pm

Richard

You have found an excellent use for a non-embedding lapping compound such as either of those two TimeSaver products. GK10, non-embedding garnet also has a place in my shop for similar work, though I think TimeSaver is superior for your application...

Kudos.
Scott Conger

Full Flow Float Valves - deliver fuel like Henry intended!


Topic author
rgould1910
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Re: Fitting timing gears

Post by rgould1910 » Sun Jul 28, 2019 6:22 pm

Thank you, Scott.


otrcman
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Re: Fitting timing gears

Post by otrcman » Sun Jul 28, 2019 8:50 pm

Richard,

How long did you have to work the gear set to achieve the results you wanted ? Did you work them in both directions or only in the engine rotation direction ? Just trying to learn how it's done.

Dick Fischer


Dan McEachern
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Re: Fitting timing gears

Post by Dan McEachern » Sun Jul 28, 2019 9:05 pm

I strongly recommend that you do not do this to correct insufficient backlash in a set of timing gears. My gears are accurately cut to run on the standard Ford center distance of 3.937" with correct backlash. If you have an issue with too much or too little backlash, we normally have both undersize and oversize gears in stock to address issues such as this. Personally speaking, I would be having a long conversation with the person that line bored that block, as its not that time consuming to check the center distance before boring the mains.


Topic author
rgould1910
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Re: Fitting timing gears

Post by rgould1910 » Sun Jul 28, 2019 11:14 pm

Dick, it took me about an hour all told. Includes mixing the Timesaver with motor oil and painting the mix on both gears before lapping. I did a little at a time working the crank back and forth about fifty times in each position. At the end I rotated the crank in one direction about a hundred revolutions and then reversed the direction for another hundred. I noticed a difference after cleaning all the compound off the gears. The cam gear entered and exited the crank gear much easier. The gears moved without binding or having any tight spots. And the front cam bearing with relatively easy to move with a drift to locate the hole for the set screw. Information about lapping gears with Timesaver can be found on line.
I've personally used Timesaver fitting rods and cranks. Also have used it on triple gear bushings and other applications I don't remember right off. This is the first time I tried it on timing gears. So far I am impressed with the results.


Topic author
rgould1910
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Re: Fitting timing gears

Post by rgould1910 » Mon Jul 29, 2019 7:26 pm

Final assembly shows a .0025" timing gear lash. Ford Service Manual shows an acceptable lash of .0005 to .003" for new gears and builds. That figure is for using Fords steel gears. With an alum cam gear, there will be slight expansion over steel, but the swelling will be minimal. It is remarkable how easy things turn.


Erik Barrett
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Re: Fitting timing gears

Post by Erik Barrett » Mon Jul 29, 2019 9:37 pm

I bored mains for years with a KRW bar. I now use a French bar and used it on this block. With these kind of machines any setup error is more likely to place the crank too far from the cam rather than too close unless you abuse the equipment with a hammer or other implement of destruction. I am very careful in the setup and have never had a complaint about timing gear mesh.
Fordially, Erik


Les Schubert
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Re: Fitting timing gears

Post by Les Schubert » Mon Jul 29, 2019 10:11 pm

Erik
If I understand correctly, the French bar is located by using link spacers from the dummy cam? This is the method I use and have for 25 years. Sure makes getting perfect gear mesh easy every time!!
All the best


Erik Barrett
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Re: Fitting timing gears

Post by Erik Barrett » Tue Jul 30, 2019 11:25 am

Les, that is how the French bar locates the bore. It has four support bearings which is an improvement over the KRW unit.

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