Top speed/rpm for lightweight T?

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Rob
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Top speed/rpm for lightweight T?

Post by Rob » Fri Oct 22, 2021 7:49 am

I’ve gone 52 mph with our brass T touring (once). I recall thinking that was too many rpm for any sustained operation. What are your thoughts of maximum sustained rpm for a T motor, with aluminum pistons?

I’m trying to decide on a diff ratio and “backing” into a ratio by attempting to compare apples and oranges (300 c.i. flat head Ford Special motor with waterpump, but unpressurized). I know Ford used 1.5:1 and 2:1 on their 228 and 400 c.i. motors for the 1911 and 1912 Algonquin Hill climb, winning their classes in 1911 and overall (2:1) in 1912.

My goal and belief is that this racer can run at highway speeds (55-65) all day long with no lugging and I’d like to plan a diff ratio accordingly.

Thanks for input, ideas. Maybe I need to check in with Montana 500 participants for suggestions?

Below, Frank Kulick driving 410 c.i. Ford Special racer 109 mph on ice in 1912:
5ABD43B2-A970-42CE-BEAB-B5589B251B40.jpeg

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Henry K. Lee
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Re: Top speed/rpm for lightweight T?

Post by Henry K. Lee » Fri Oct 22, 2021 8:29 am

Rob an auxiliary transmission is definitely your friend in preventing lugging the engine. We have two speedsters, one with pressurized mains/OHV stoker.., Chevy 3 speed/Ruxstell 3 to 1, all day at 75 mph with burst up to 95 mph. The other, flat head, high compression head with all the whistles and bells, Warford 3:63 to 1.., 65 all day long.

Hope this Helps,

Hank

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Re: Top speed/rpm for lightweight T?

Post by Kaiser » Fri Oct 22, 2021 8:31 am

Hey Rob, crazy idea maybe, but for experimentation purposes you could fit a Model A Banjo rear with a Halibrand Quick-change....
It would make finding the right ratio for the Special a lot easier, and when the right ratio is found the Halibrand will be a quick sell.
It would require some 'light' fabrication to fit the rear spring and the torque tube, but hey, that's whats part of the fun right??
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A rear with Halibrand Quick-change.jpg
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Re: Top speed/rpm for lightweight T?

Post by speedytinc » Fri Oct 22, 2021 8:53 am

Henry K. Lee wrote:
Fri Oct 22, 2021 8:29 am
Rob an auxiliary transmission is definitely your friend in preventing lugging the engine. We have two speedsters, one with pressurized mains/OHV stoker.., Chevy 3 speed/Ruxstell 3 to 1, all day at 75 mph with burst up to 95 mph. The other, flat head, high compression head with all the whistles and bells, Warford 3:63 to 1.., 65 all day long.

Hope this Helps,

Hank
Dittos. Without a rux or other lower gear choices 3.25 could be an acceptable compromise. My roadster functions ok in direct with this ratio(eliminating rux use) 3.00 or 3.07 is much less friendly for starting & braking, but would be the ideal racer end ratio. (Still need a gear reduction for street use.)


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Re: Top speed/rpm for lightweight T?

Post by Been Here Before » Fri Oct 22, 2021 9:59 am

OK, this discussion mentions ratios and speeds. But at what RPM? Tyre size considered? I seem to remember that 30x3.5 and a 2:1 ratio. Transmission at 1:1, 80mph can be achieved at about a RPM of 1760. What is the top rpm for the T motor? The 410 c.i. Ford Special racer at 109 mph what was the engines top RPM for the motor?


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Re: Top speed/rpm for lightweight T?

Post by TXGOAT2 » Fri Oct 22, 2021 10:09 am

Opinion: Stock crank, aluminum pistons, engine balanced: 2,000 RPM.

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Re: Top speed/rpm for lightweight T?

Post by Rob » Fri Oct 22, 2021 10:32 am

Thanks guys, all good ideas. This racer has 32 inch wheels (as per Ford factory drawings for the 300 c.i. racer. I thought of a Model A configuration, as well as a new Warford. However. Everything is so “exposed” I hate to deviate from the original appearance.

I wish I knew what ratio Ford used when they ran the big racer 109 mph. I know when it beat the Blitzen Benz (fastest car in the world at the time, including 1 mile circular track record) in the one mile timed race the Ford averaged 72 mph from a standing start.

At Algonquin hill climb in 1912 the big racer had 2:1 gears and averaged 65 mph from a flying start. Below is what the pumpkin looked like on the big racer in 1911, when it had 1.5:1 gears:
308557EC-7183-44AB-8D8B-82E6D8502615.png
D152EEA6-FDA1-428A-99CA-D42D0C902892.png

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Re: Top speed/rpm for lightweight T?

Post by Henry K. Lee » Fri Oct 22, 2021 10:59 am

Something to add.., we only use Made in USA, 21” or 20” tires for speeds above 45 mph. Have had 30 x 3 1/2” separate at 50 mph.

Hank

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Re: Top speed/rpm for lightweight T?

Post by Kaiser » Fri Oct 22, 2021 11:34 am

The A Banjo/Halibrand combo is not meant as a permanent instalation, just to experiment with ratios, once ratios are worked out just replace with your Special's own rear end (with appropriate ratio Crown and Pinion fitted) and sell the Hallibrand to the first Hotrodder to bid good money for it 8-)
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Re: Top speed/rpm for lightweight T?

Post by Norman Kling » Fri Oct 22, 2021 12:17 pm

I notice you live in Nebraska so a higher gear ratio would probably work for you. I have a 22 standard runabout with a 3:1 in it. It also has Ruckstell. It zips right along on flat or downhill. Since I don't have a speedometer, I don't know my top speeds. However, living here, with hills I find I use Ruckstell more than on my other T's with standard gear ratio. Another thing I find interesting, is up a 6% grade, on tours the other T's go along about 25 in high gear, and I can pull the same hill at about 35. However, in tours, I almost always have to use Ruckstell because it lugs on the hill at 25. Also when pulling out from a stop, on a small grade where I can use standard low and high, with my higher ratio, I have to go from low to Ruckstell and can't get into Ford High, sometimes never and others after I get going about 25 up the hill. I know there are some hills in Nebraska, but not many steep ones, so maybe a higher gear would work for you.
Norm

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Re: Top speed/rpm for lightweight T?

Post by George Mills » Fri Oct 22, 2021 12:50 pm

Rob. my 15 Roadster creeps up to 52-55 when I'm not looking and on country roads. It's stock...and it gets there because I don't hear it whining. I've driven that white speedster that circulated around for a while with the gal in the swimsuit and heels cranking it...that did 60 in a heartbeat and ran sleek but got scary, one good run was enough for me.

I'll share a very common practice done in the first decade of the 20th century concerning castings. Having patterns carved cost something, experimenting with shrinkage took a couple of try's. the iron part was the easiest to do! In my research on other industrialization windmill chasing, I find many large company of the time had drawings where the material spec would say, "Found pattern at Chicago Iron". Same for other cities but always the 'pattern found at' comment.

A deduction on my part... that tells me that they probably did not go through a development process for small quantity work. Simply find a nice day, walk through the local foundry yard as they stored customer specific patterns for free (made it hard to shop a casting buy), and point to one with a 'close enough' thought. Tell the ironmonger you'll buy two or three poured to that pattern and...the parts just showed up. In many cases the ironmonger already had poured stock around the corner. Even then they knew that aged iron machined better and stayed stable longer so if you wanted the appearance of a quality iron foundry...just pour an order ahead for a few good customers on your own dime...then produce what are now aged castings to the customer on his order.

Just a thought...that pumpkin has an even chance it started on someone else's design. The 'who' is the bottom pickle in the barrel.

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Rob
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Re: Top speed/rpm for lightweight T?

Post by Rob » Fri Oct 22, 2021 7:57 pm

Thanks again guys. Maybe this will help.

This is a video from this summer. You see the racer start out, shift pretty easily into high, and easily accelerate to 50 mph. This is with 3:1 gears. We've had it up to close to 70-75 mph, but as the numbers will show below, that's pretty high rpm. I'm leaning toward 2.25:1. 2.5 doesn't seem like enough of a step up to justify the expense, and 2:1 may just be too tall.

Peter Fawcett in Canada is helping me, and as he said, we can make a set of gears to drop down if we need to, as he's building a wider pumpkin to accommodate a much larger pinion (see the original racer pic above).

Video going to 50 mph. It's an effortless run up:

https://www.dropbox.com/s/n7ji4bf6cx0ip ... h.mov?dl=0


Comparison of 3, 2.5, 2.25 and 2.0 ratio to rpm comparison. I used the top end of 2363 rpm just because that's what it would take to reach 100 mph with a 2.25:1 diff:

0A0511A2-3D15-4F88-91E8-4E0B2EF37058.jpeg


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Re: Top speed/rpm for lightweight T?

Post by Les Schubert » Fri Oct 22, 2021 8:10 pm

My old speedster would pull hard to about 4200 rpm (where the valves would start to float (flathead Sherman head, T springs)). Counterbalanced A pressure crank,Stromberg 97 carb. Capable of 100 mph with 3.63 axle. 19” model A wheels
I’m now building a coupe with the identical engine. Freeway should be no problem!


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Re: Top speed/rpm for lightweight T?

Post by TXGOAT2 » Fri Oct 22, 2021 10:15 pm

A full fendered T coupe will generate a lot of aerodynamic drag once you get above about 35-40 MPH.


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Re: Top speed/rpm for lightweight T?

Post by Loftfield » Sat Oct 23, 2021 6:46 am

I watched a video recently in which the owner of a 1910 Pierce was asked how fast it would go. His reply: 45 or more, but I only have brakes for 32. 'nuff said!

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