Overdrive - Lincoln vs. Columbia

[SUHRsc]

Tim,
I was actually thinking the same thing with the gear ratios.

LZ is sprung weight though compared to the Columbia

[Tim Ayers]

Originally Posted by SUHRsc

Tim,
I was actually thinking the same thing with the gear ratios.

LZ is sprung weight though compared to the Columbia

I guess the weight thing makes sense.

[Bruce Lancaster]

On the gear ratios...think through your choice of rear gears first, both gear ratio and ratio developed with OD engaged. Lincolns went with 4.44, allowing the close ratio trans gears without the too-high syndrome of LZ trans gears in many hotrods, then got back the cruising speed by adding overdrive.
70% of 4.44 is...

[Tim Ayers]

Originally Posted by Bruce Lancaster

On the gear ratios...think through your choice of rear gears first, both gear ratio and ratio developed with OD engaged. Lincolns went with 4.44, allowing the close ratio trans gears without the too-high syndrome of LZ trans gears in many hotrods, then got back the cruising speed by adding overdrive.
70% of 4.44 is...

If my math is correct, 3.10 @ 70%. So 70% of 3.78 is 2.64, right?

Seems like a nice ratio to be going down the highway at 75-80 mph...

I would think taller rear tires (7.00 or 7.50's) will also come into play since I think LZ's had 6.00's

Maybe 4.11's would be a nice compromise between 3.78 & 4.44's since it would be 2.87.

[Kahuna]

What are the transmission ratios in the above trans? 1st & 2nd?
Seems that Lincoln trans/OD would be about perfect in a normal Ford Car or Hot Rod with a 4.11:1 rear axle. Some consideration being given to tire size, etc

[Tim Ayers]

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Originally Posted by Kahuna

What are the transmission ratios in the above trans? 1st & 2nd?
Seems that Lincoln trans/OD would be about perfect in a normal Ford Car or Hot Rod with a 4.11:1 rear axle. Some consideration being given to tire size, etc

The ratios below were taken from Mac VP's site.

29 tooth: 3.11 1st, 1.77 2nd

28 tooth: 2.82 1st, 1.60 2nd

26 tooth: 2.33 1st, 1.577 2nd

25 tooth: 2.12 1st, 1.43 2nd

[SUHRsc]

I have a model-A with an overdrive in the torque tube.... I usually will run 2nd OD and then go into 3rd.... rather then 3rd and then the 30% drop

The problem with this car is that it has 25 tooth trans gears. 3.54 rearend and 7.00x16 tires...
So it is a real dog off the line.. but it will go as fast as you feel comfortable driving a light weight model-A.

The car will more or less idle down the highway at 65mph.

It has a very healthy model-B engine in it.

[Kahuna]

Thanks, Tim

SUHR

You'd be in much better shape with a 4.11:1 rear axle ratio. Just my opinion

[SUHRsc]

I agree Kahuna. I bought the car like this but I'd like to work it out better in the future.

[Bruce Lancaster]

Good heavens, doesn't anyone have an Isky Dream wheel anymore? Stamped with Ford and LZ gear ratios, and does all your calculations without any batteries...

[V8COOPMAN]

Originally Posted by Bruce Lancaster

Good heavens, doesn't anyone have an Isky Dream wheel anymore? Stamped with Ford and LZ gear ratios, and does all your calculations without any batteries...

And it cost a whole $Buck! DD

[Kahuna]

No Bruce, I don't. I havta do all this stuff in my head and a calculator.
When I was a kid I didn't have the dollar. ha ha

My suggestion was to TRY to make the car as driveable as possible.

I always refer to the original Ford ratios when thinking about making changes:
An Example:
I have Ford T&C gears in my 32. First gear ratio for Ford (stock) was 2.82:1
Mine is 2.78:1 (pretty close), with high gear being 1:1, before trying to figure the O/D ratio.
Then this O/D which is .78, creates a final drive ratio of 3.21:1, using an axle ratio of 4.11.
Then figure tire sizes. In my case, 29 inch tall rear tire.
Good driveability, about 2300 rpm @ 65 mph (in O/D), and reasonable mileage 18+
Now, having had this arrangement for the past couple of years, it could probably be improved because the engine has NO difficulty pulling at all. I could have gone to a 3.78 rear and had even better mileage, and given up almost nothing as far as acceleration
I kinda think it's all a guessing game, but you can get it close by doing the research.

BTW, Bruce
I still haven't gotten around to trying the Evaporust in my 39. Soon, I hope

[Bruce Lancaster]

Hah! MY Dreamwheel was FREE, found in the glovebox of a dead '46 Ford in a junkyard 50 years ago...

Good examples of calculation! Think why Lincoln went to a low gear with OD, think about how this allowed a closer ratio gearset...

[Frank Miller]

Ford ran 4.11 in the rear end of overdrive cars in 49-51 and maybe then some. These are relatively heavy compared to an earlier hot rod. I have 3,78 with the 30% overdrive and it is not a problem. Race cars don't run overdrive as far as I know. You just need to figure out what you want the car to do. It will always be a trade off.

[Kahuna]

Absolutely right, Frank

[Bruce Lancaster]

The effect of the OD is to reduce the number and severity of tradeoffs...the total package can allow lower gears at low speed for acceleration and higher gearing at cruise speed...

[Mac VP]

The LZ overdrive gearbox will accept all four gear combos.....29, 28, 26, and 25T clusters. Normal assembly procedure of pulling up the cluster gear up after installing the main drive gear and mainshaft.

[Highboy34]

I ran a 37 Cabriolet with a stock 221 inch engine, 26-tooth Zephyrs and a Columbia with a 4:11 gear. Tires were stock 6:00X16s. Great ratios around town and on the highway.

[Chisel]

Best answer is a T170. Looks stock, bolts in, no cutting frame, all synco 4 speed with overdrive, small with al case.

[Tim Ayers]

Originally Posted by Chisel

Best answer is a T170. Looks stock, bolts in, no cutting frame, all synco 4 speed with overdrive, small with al case.

What is T170 from? Is this one of those F series O/D trans?