MTFCA Forum

Can anybody identify the metal timing gear pictured? The number on it is: T415B and looks to be in pretty good condition. I can't locate any reference to that number.

Given the choice, would you install the used metal one of the new nylon one?

R/ Roger.

The steel 4 spoke was the first helical gear following the straight cut cam gear. I'm assuming following the introduction of the Ford electric starting system.

And, I would use the steel gear, given the choice !

Looking at it will not tell you much, needs to be fitted for a check of lash.

The only downside to a steel gear is that it is noisier than the non-steel gears. I will take noisier, any day, over a propensity to break and lose teeth like the non steel gears do. Jim Patrick

It's a Model T. You won't hear the timing gear over all the other noises.

Agree, agree, agree. I too would prefer the noise of a steel gear set over the alternative of a dead engine due to tooth failure.
I believe steel is 100% necessary if running a generator.
Alan in Western Australia

I have probably replaced 50 timing gears in modern cars. In every case the change was necessary because the nylon gear failed. If there is any reasonable alternative, I will never install a nylon timing gear. I have also never noticed any difference in the sound of the steel gear as opposed to the nylon gear (actually there was a difference in noise - with the failed nylon gear the engine would not run. With the steel gear installed it would).

And to counter with; when I lost my center main, also broke some of the teeth off the nylon gear, except; only took the top part off some of the teeth and cracked others, the car still ran. The lost teeth were still about 1/2 there and there were cracks were about 1/2 way down the on others. When this happened, I was operating outside my norm. Tried to shift the Warford from underdrive to direct at too high RPM while still on a slight incline. While I may have stripped the remaining 1/2 cracked teeth off later(?), I was able to drive the car off the road before loading on trailer and when got home into the shed.

There are two types of Ford steel helical gears. Four spoke, and three spoke.

Ok, thanks. Steel it is! I'll check the backlash when I get it together.

Anybody need a nylon one?

R/ Roger.

I’ll take the nylon gear. I’ve run various fiber and nylon gears for 48 years without a problem. But I am scrupulously careful about 100 mm cam to crank spacing and generator gear lash.

Was there not a thread a few years ago about some nylon gears made with the wrong angle on the gears. This is what caused the teeth to shear off. Dan

Steve Jelf wrote: ↑

Mon Oct 19, 2020 12:12 am

It's a Model T. You won't hear the timing gear over all the other noises.

Ha!! This is so true.

Les Schubert wrote: ↑

Mon Oct 19, 2020 4:43 pm

I’ll take the nylon gear. I’ve run various fiber and nylon gears for 48 years without a problem. But I am scrupulously careful about 100 mm cam to crank spacing and generator gear lash.

I'll keep you in mind, Les.

R/ Roger.

I read somewhere that some consider the 4 spoke steel gears to be superior to the later 3 spoke type. I can't remember the details. I wonder if all the replacement nylon/fibre/whatever are used for any other reason than either cheapness or noise reduction. My preference has always been for a new steel crankshaft gear and an aluminium timing gear.

Allan from down under.

Old thread but I will chime in. I have sold and installed "a few" nylon timing gears, never heard of one failing unless something stopped the cam from turning first. I have also used aluminum and bronze - they rang like a bell, took them out after a few miles and put fiber or nylon back in.

That being said - I found this thread looking for information on the early straight cut gears. I'm still looking.

Why? "spoilers"... https://youtube.com/shorts/42w_CPoJmN0

Anyone know what year they switched to helical, or any relevent information on straight cut? Are they reproducing them? Advantage / disadvantages?

Helical gears are stronger and quieter than spur gears. They may introduce some mild side thrust, which would probably add to quiet running. I don't trust nylon gears in auto engines. I would trust an original type bakelite/fabric gear if it was not decades old. Cast iron/streel helical gears are the most reliable, especially where a generator is involved.

I run fiber gears on nongenerator Ts without any issue. Since you can find them in a couple oversizes, it's not difficult to set them up correctly. I wonder if some of the failures we hear about are due to a bent crank or cam. I've seen both.

The Ford cam gears are not steel they are malleable iron. All Ford T crankshaft gears are steel. Just FYI.

TheSpeedsterProject wrote: ↑

Sat Dec 10, 2022 3:46 pm

I have also used aluminum and bronze - they rang like a bell, took them out after a few miles and put fiber or nylon back in.

If any timing gear “rang like a bell” the centers, or lash, or something else wasn’t quite right…

Advantages of helical and spur gears
Helical are quieter
Spur or straight tooth are stronger, more efficient, and easier to manufacture

Art Mirtes

Art M wrote: ↑

Sat Dec 10, 2022 11:17 pm

Advantages of helical and spur gears
Helical are quieter
Spur or straight tooth are stronger, more efficient, and easier to manufacture

Art Mirtes

Helicals are really no more difficult to manufacture than spurs. Usually just requires a different change gear ratio between the gear blank and the spriral hob.

Jerry VanOoteghem wrote: ↑

Sun Dec 11, 2022 8:40 am

Art M wrote: ↑

Sat Dec 10, 2022 11:17 pm

Advantages of helical and spur gears
Helical are quieter
Spur or straight tooth are stronger, more efficient, and easier to manufacture

Art Mirtes

Helicals are really no more difficult to manufacture than spurs. Usually just requires a different change gear ratio between the gear blank and the spriral hob.

Dan's photo above has me a bit humbled. Yes there's a bit more to it than gear ratios.

I suspect that timing gears in 4 cylinder engines tend to be noisier than those in 6 or 8 cylinder engines, since they are less uniformly driven and loaded. I'd also think that a Model T Ford's low speed 4 cylinder engine, which has no cam-driven oil pump, would tend to have especially noisy timing gears. Lack of a harmonic balancer might further contribute to timing gear noise at certain speeds.
The constant drag of a gear type oil pump would tend to pre-load the timing gears, which would contribute to quieter operation. A generator on a T engine contributes its own noise, adds another gear, and provides very little pre load at low speeds.