Switching from 3:1 to 3.25:1

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Model T Ford Forum: Forum 2016: Switching from 3:1 to 3.25:1
Top of pagePrevious messageNext messageBottom of page Link to this message  By Keith Townsend ; ^ ) Gresham, Orygun on Friday, August 05, 2016 - 04:41 pm:

On my 1919 touring I have a Ruckstell with 3:1 gears. I find that even with my engine improvements, the 3:1 gears are just a little too tall.

I plan to replace the 13 tooth pinion with a 12 tooth pinion. How many ring gear shims will I need to slip in?

: ^ )

Keith


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Friday, August 05, 2016 - 04:55 pm:

Keith
Thank you for asking this question. It is something I'm thinking about doing too


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Robison on Friday, August 05, 2016 - 05:04 pm:

I think gear shims are a bad idea. You're better off the shim the carrier assembly.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan McEachern on Friday, August 05, 2016 - 06:03 pm:

Keith- I agree with Mike- shims will allow the ring gear to slide on the carrier,with the ring gear bolts taking all the shear load rather than the clamp friction between the ring gear and the carrier flange. Best way is to shim the thrust washers or cut one down on a lathe until you are happy with the mesh, and then either machine down a bronze washer or make a special thickness one and that way there are no shims anywhere. Access to even a small bench lathe is all you need to do it this way.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Clayton Paddison on Friday, August 05, 2016 - 06:46 pm:

I will third Mike's suggestion Keith. Ring Gear shims seemed a bit "ify" to me.


Top of pagePrevious messageNext messageBottom of page Link to this message  By WilliamThomas Forsythe on Friday, August 05, 2016 - 07:09 pm:

Hello Keith:I can agree with your choice of changing 3:1 to 3.25:1 as I went thru the efforts back in 2012.Obviously the engine now turns 10% faster producing more torque at all speeds. As we don't intend to drive our T's more than 45 or 50 mph, the 3.25:1 is ideal. I think I've clocked over 8000 miles since the change. Very pleased indeed. With a good powerful engine, we really don't need the Ruckstell. I regularly stay in High Ruckstell all the time. Only on the steepest of hills do I go into Ruckstell Low. As registered with my tachometer, speedometer and GPS;@ 45 mph my engine is turning 1600 rpm; and @ 50 mph it is turning 1800 rpm - both in the good torque range. Tom Pulling rear end for 3.0:1 to 3,25:1


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett - Australia on Friday, August 05, 2016 - 08:15 pm:

Keith, I have gone to the same ratio in my roadster Ruckstell. I have yet to drive it. It went together without ring gear shims. As Dan said, you just need to work on the bronze thrust washer on the right.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Friday, August 05, 2016 - 08:23 pm:

Please forgive my confusion - On a Ruckstell, isn't the position of the carrier assembly set by the big ball bearing on the driver's side? Doesn't the bronze washer on the passenger side get sanded or shimmed to set the clearance between the carrier assembly and the passenger side rear axle housing?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Phillip Maurici on Friday, August 05, 2016 - 08:33 pm:

Stock 3.64:1 is even better. I have done a speed run with GPS at 55 mph. I have a scat crank. 280 can with 7 deg. advance and 8:1 head.
Car has lots of pep and loves 40-42 mph cruse speed. The Prus 8;1 head makes a lot more improvement than any up grades
I also removed a Z-head in my other T and installed a 8:1 and improved top speed and torque. That motor is stock except for head.
No over heating either. Even in Florida's heat.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Clayton Paddison on Saturday, August 06, 2016 - 07:58 pm:

Keith,

See, the right answer here is not to step the gearing down.....it just means it's time for a hotter motor.

I think a Fronty with a small blower would do the trick :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Saturday, August 06, 2016 - 08:33 pm:

Clayton
I'm interested in your thoughts on the "blower". MANY years ago I tried a Corvair turbo and Carter YH on my A cranked engine. It didn't work to my satisfaction. Ultimately went Sherman head and Holly 94. I'm thinking about trying the turbo from a Ford 2.3 engine. I'd be interested in your thoughts
Thx


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bruce Spainhower - Portland, Oregon on Sunday, August 07, 2016 - 02:07 pm:

I already had a 12-tooth pinion when I rebuilt mine, so only some of this will apply. The issue with mine was to correct some severe end play while maintaining the correct gear lash. I started in the middle by replacing the single fiber washer I found with a bronze one of the correct thickness. That dropped the axle end play from .030 to .006. Then I assembled the complete axle, minus the Ford side housing. It's tricky, but you can attach a magnetic base dial indicator to the Ruckstell housing in such a way to get the probe to hit a pinion tooth squarely. You can then read the gear lash directly. (Sorry, I didn't get a photo of this.) Add or remove shims until the gear lash is .010.

In the case of my axle, the previous owner had too thin of a shim between the axles, too much slop in the bronze thrust washers (at least they were bronze), and too many ring gear shims to make up for it. It worked fine driving straight, but a curve took up all the slop, which made the ring and pinion too tight, and it would grind.

By the time I was done getting the tolerances all correct, I ended up removing three ring gear shims. I suppose you could calculate how many shims it would take to go from a 13 to a 12 tooth pinion, but it was easier for me to do it trial-and-error. It's a lot of assembly and disassembly, but it's satisfying when you end up with a solid, noise free axle.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Clayton Paddison on Monday, August 08, 2016 - 01:37 am:

Les,

I was gonna turbo my Roadster originally, but the project was a bit much for a beginner and the older bearings I had at the time just wouldn't have lasted long.

I had planned to copy a setup that Mike Robison and Tom Carnegie had built about 10 years ago. I believe it also used a 2.3 Ford unit and was seTup to output about 2 to 3 lbs of boost. Seemed to go pretty good. I had one built and may put it to use on another up coming T.

I suspect you could also run a small MG blower or one of these guys... :-)


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