I bought a engine from a guy, that he did an exchange with Mac's in 1997. Engine was still wrapped and all looks new. What I am concerned about it has a fiber timing gear. Since the timing plate is not installed, need some input, would you put an aluminum one one it or leave the fiber gear.

There have been enough failures with fiber timing gears on T's to convince me to use any metal alternative before the fiber gear. Make sure the gear on the crank shaft is also new - not fun replacing that one when the engine is installed.

Sam:

I like the nylon ones, as well.

Sam, I think the trouble is that there are good ones and bad ones. Sort of hard to tell the difference. Many guys have run fiber gears for years with no generator. Some guys have had them fail, I for one, but it did run many thousand miles..
It's certainly easy to change when you have it out. PS when it fails there is no limping home...

I would change it without thinking twice.

I agree with the others; change it before installing the engine in a car. Better safe than sorry at the wrong time. When I put my Speedster back together a few years ago, the engine had been rebuilt in 1980, but had never been run. Had a new fiber timing gear and a new crank gear. Pulled the fiber gear off and replaced with a new aluminum timing gear. All's well so far, and I'm not concerned that it will fail anytime soon. The money spent is worth the peace of mind you'll have. JMHO

I like the fiber gears just fine. I have my theories on why some have failed, but I will decline to get into a online "fight "

Google the following:

timing gear mtfca.com

Lots of opinions. Spend some time and view by date- recent first and go back in time. The pictures alone should help you make a sensible decision.

In my case, I've never seen an aluminum or a steel one lose any teeth.

Since the timing cover is off now is the easiest time to install a new gear. This is also a much better time than to have to tow the car in and take off the radiator to get to it.
Norm

Sam:
also , when you install the timing cover ...regardless of the gear choice ...be sure to center the timer cover to the camshaft to assure proper "timing' of your ignition if you are using timer and coil system ...always an optimist Gene French

Thank you for the advise from all of you and MTFCA forum
It was a great help. Happy Holidays. Sam

Don't forget to also install a modern seal on the cam and it's a perfect time when you have access to install one on the crankshaft so you don't have any oil leaks dripping from the front and blowing back all over the rest of the car..

What's wrong with using a stock gear if it's in spec?

The fiber timing gear has always been kind of a "mystery" to me. In high school in the '50's, I had a Model A that I drove daily in Chicago, summer & winter and it was an extremely dependable car. You can believe this, or not,....but when that first engine "died" due to an old and poorly repaired crack in the block that opened up right under the water pump. And being a kid with limited "funds", I found another block and basically pulled the guts out of the cracked block engine, and put them (INCLUDING THE FIBER TIMING GEAR THAT LOOKED FINE AT THE TIME) into the good engine block. Again, I drove the car daily during my two years of college and off & on for several years after that until I finally sold the car in 1966. It always ran good and never had any trouble with that fiber timing gear!

That timing gear actually had a "quality feel" to it as it seemed heavy and hard as a rock. Now then, having said that, today's fiber timing gears are obviously of poor quality and many failures have been discussed on this forum. Almost seems like today's fiber gears might be manufactured in the same factory as Presto Logs! FWIW,.......harold

Les S. - Maybe nowadays, there might be more than one manufacturer of fiber timing gears, and accordingly, some good and some not so good, huh? It certainly is odd that some have no trouble with them and some do. I think that just to be safe, I'd use any metal gear rather than take a chance on getting a bad fiber gear,.....again,.....FWIW,......harold

My guesses: McEachern bronze gear, best; NOS original, also best; aluminum, not best, but good; nylon, no thanks. Not a guess: fiber, never. Some say metal gears are too noisy. Really? You can hear them over the other Model T noise?

I agree with Steve. Is people's hearing so good that they can tell if there's a metal timing gear in there? Between road noise, rattle, trans noise from straight cut gears turning, And a little valve clatter, I don't know how anyone could discern timing gear noise. Plus, I never talked to anyone who actually claimed they could hear timing gear noise.

There used to be fibre gears made with laminated woven fibre sheets. This was the same method of manufacture used in modern engines in the 60's and later.
The ones we can buy today are made from macerated fibre bonded together and then machined. They don't last. The same applies to fibreglass boats. Hulls formed using cross laid sheets of fibre are considerably more durable than those made with chopped fibre shot into the mould.

Allan from down under.

I had my engine re-built in 2005 and a fibre gear was installed. This was a 1917 block so no generator. Eight years down the track, I checked it, and it was like new.

Two years after that, I had the motor out for a transmission rebuild and was amazed to see many teeth missing off the fibre gear. I now have a Nylon gear on.

I guess they have a life span, and I was lucky not to be left stranded.

I bought one the other day just to use for a template for marking bronze advance timing gears.

On my '27 roadster that I did the engine in '78. It now has in excess of 20,000 miles on it. My '13 touring that I built in 2000 has in excess of 10,000 miles (the Firestone tires are about 3/4 worn). They both have almost BLACK fibre gears. Now I am "fastidious " about how I build my engines. On the '27 I used a oversized gear because I centered the crank between the bolt holes when I line bored it. By the time I built the '13 I had figured out what the correct spacing to the camshaft was (100 mm), and now locate the line boring bar using a "link" to the cam bores. This way I get perfect fit of the standard size gears every time.
Obviously on the '13 there is no generator to be concerned with. If the engine has a generator I then fit the generator BEFORE I install the front cover. Some of the gasket sets I've seen have several gaskets for fitting the generator bracket. I fit the generator gear for correct gear lash (a piece of writing paper should JUST fit by the gear teeth) (perhaps.002-.004 lash). Perceptible lash but no real "click"!! I handle the gear as if it was tough but FRAGILE.
On racing engines I do use aluminum cam gears as then I'm using BIG radical camshaft and high revs. On my new all aluminum 5 main engine I ended up needing a.005 oversized gear which I was able to buy from the local supplier (George Moir at Edmonton). It is using a OHV special Stipe cam with a Chaffin BB Rajo.
I still have a small inventory of the black fiber gears and will continue to use them on "street " engines. I may well be more fastidious than most engine builders, but that has served me well in 40 years of T driving

Some of the guys like them. At least they haven't walked home. Yet. Fact is they fail. Period. Metal gears might get noisey with time but I'd rather hear noise in my garage than no noise in the street. Dump it. Save yourself some grief.

Ah Les?

Did you have the black ones made?

First time I've heard of near black...but I don't get out much...

Curious on them...can you see the fiber? If so is it chopped or is it woven fabric with an obvious warp and weft?

From back in the OLD days it seemed to me that the ones with visible woven fabric, looks like Micarta, rarely failed,but the ones that appeared as above were not as strong. Dave in Bellingham,WA

Thanks Dave...

I've been planning to comment on that very possibility when Les said he had 'near black' that wears like iron....

Anybody of Model A co-dependency? I heard somewhere that some years had fiber gears with metal hubs right from the factory???

George
I simply bought these black gears from the local parts supplier near here.
I hope the attached photos help

Thanks Les,

Can't tell if it is chopped fiber or layered cloth from here...

But the super dark brown almost black is most probably a form of Bakelite, with mixed phenols and formaldahyde. Mother natures self curing original 'epoxy'.

My reason for asking things is that I think and can only say think that while there are several reasons for fiber gear failure including human error...is that I think the later chopped fiber is inherently weaker than the cloth fabric fiber where in the era the cloth was impregnated with? Ally-oop....ASBESTO'S and therefore why they wear like iron...

And the goo that binds on these newer things might be nothing more than acrylic resin...whereas the originals from the era were all phenol/formaldahyde self cooking resin (Bakelite, Beakalite, Micarta). There was a G.E. product that came along later...Micarta by another name and resin, but that is one where Westinghouse did prevail in suing GE and won and insisted on a cease and desist from manufacturing.

George
I'm going to guess that it is chopped fibre.
All the pictures that I have seen of ones that have failed appear to be quite a light tan colour, so your theory could certainly have merit!!

Fiber gears were quiet, worn in easily, so the manufacturers liked them. My model As all had fiber gears---BUT they were woven and used the Bakelite process. Today, you don't know for certain what that timing gear is made of, so for Ts I lean towards metal gears. Too many spurious parts out there. I recently helped in the repair of a 1922 Buick that hadn't run for years. The conclusion was that something caused the fiber timing gear to strip a few teeth. The replacement was old stock, also Fiber (with metal center) and it wasn't cheap, if my memory is correct, about $225.
We T folks are spoiled when it comes to parts availability!

Then there were some poor short lived gears made in the late seventies or early eighties that could still be on parts shelves or installed in rebuilt engines that have not been run yet.
I heard about those in '87 so I stay away from anything but metal unless I know they were made recently.

Yeah, I know. There's a bunch of them out there that haven't failed. There's also a bunch that have. Even Mister Thrifty isn't going to risk this happening again just to save a few bucks.

Interesting in that Steve"s gear is lighter tan colour. I wonder if there is a significance!!

Les,

The significance might just be lighting.

The only fiber gear I run was probably made in the 40's and has the brand name "Cylent" on it. Been in the engine for 40 years now so I guess it's a good one. Wouldn't use one of the new ones if you paid me. Have had 3 of them strip in 3 different T's. Can't prove it, but I'll bet lots of broken cranks have been caused by stripped gears, getting way out of time and catching just a bit more to make a plug fire on the upstroke.

Several factors: The crankshaft bearings must be in perfect alignment with the camshaft. The gears on the crankshaft and generator must be in perfect condition. The valve springs should be correct tension. A difference between the early T's and the later ones and the A's is the generator which is driven off the camshaft. That gear must also be in perfect alignment with the camshaft gear. The metal gears might be a bit noisier, but they are much more forgiving. The earlier cars and the Model A's would not have the cam gear turning the generator so they would only have wear caused by one gear while those pushing a generator have wear on both sides.
Norm

I agree with Norm, however consider that I and others have gotten many many years of use on generator cars (coming up to 40 for me). Not arguing,just saying

The shop that did the restoration on my '24 generator car for the previous owner (actually, it came to me with an alternator) told me they installed a fiber cam gear in 2008. The previous owner hardly drove the car at all. So far, I have put 3000 miles on the car, so far so good, keeping my finger crossed.

Mark

Just an opinion, I would replace with metal before the driving season starts. I would also check the valve timing with the current cam as if its near stock, you would benefit from getting a gear with 1/2 tooth advance. This will help a great deal in low end torque.

I had a fiber gear fail and view them like smoking. It isn't if there is bad news on the way but rather when it will arrive. Imagine if you drove out west for the national tour next year and the gear crapped itself on day 2. I'd rather change stuff like that on my time table rather than its. Just an opinion.