1931 Frod Model A - Laminated Timing Gear

[KenJT]

Among other problems I've had with my Model A, my mechanic found that the timing was off. He had a lot of trouble getting the timing right. He ended up asking me for the crank, thinking (I guess) that he could slowly turn the crank to help fix the timing. The next thing I knew, he was telling me he discovered that the laminated timing gear had broken up a bit. It seem very suspicious that, for a 90 year old car, this gear would suddenly fail. I doubt the crank was used much, if ever. Can someone tell me if it's really possible for this gear to fail over time or could it have been caused by my mechanic, who although very good is not an expert when it comes to Model A's.

[pkhammer]

  Using the hand crank won't hurt the timing gear. The laminated (fiber) timing gear is what I assume he is talking about and like any mechanical part can fail. Perhaps it wasn't getting oil for some reason? I doubt that this engine has gone untouched for 90 years but I assume it's possible. In any case it's easy to inspect. Just remove the timing gear cover from the side of the block toward the front of the engine. Four bolts (two in the block, two in the front cover) and the cover will come right off exposing the timing gear.

  To set the timing on a Model A it's best to find TDC for #1 cylinder then make sure the points are set in the "just ready" to open position on the little cam in the distributor. It can be rotated easily by loosening the screw in the center directly under the rotor button. A special wrench to hold the cam while the the screw is being loosened and tightened will be necessary. The rotor button obviously needs to be pointing toward firing the #1 spark plug. Make sure the timing lever on the steering column is in the "up" position or maybe one notch down.

[Bloo]

That is exactly what happens with fiber timing gears of all sorts. They fail suddenly and leave you to walk home. I can't speak to the model A specifically, but laminated (and another type of fiber gear I don't recall the name of) were common in that period. The trouble is a camshaft, with the valve springs acting on it, is trying to jerk back and forth on the gear as the engine turns. Eventually the gear fails from all the pounding. A solution to this problem is an aluminum gear, but aluminum rings like a bell, and tends to make knocking noises at low speeds. It gets worse as the gear wears. It can be pretty obnoxious and sometimes sounds like bearings knocking. Fiber gears were commonly used in passenger cars because they were quiet, but reliability was always suspect. Trucks sometimes got aluminum gears.

 

 

[JimKB1MCV]

  When I was in high school in the late '50s I drove a '30 Model A Fordoor and as we are prone to do I accumulated  a pretty good stash of spare parts, most used but still good, sourced from various relatives and neighbors.

  in the space of those four years I sold two of the fiber timing gears to local college students who were set afoot by Model A timing gear  failure but never happened to need one myself.  My understanding is that was a known point of failure on the A, along with the pesky condenser in the distributor close to the exhaust manifold.

 

  The parts went away (mostly) in the ensuing years, the remaining item was a kingpin set that I used on another Model A project around 1993.

 

  Labor Day weekend 0f 2018 (?) saw my Studebaker President dead on the roadside with a stripped fiber timing gear but thats another story.

 

  The hand crank is the best way to turn the engine to set the timing on the Model A if the engine is at all tight, it indexes on a ratchet nut on the crankshaft, no contact with the fiber gear.

 

 

 

[KenJT]

I'm hoping to hear from my mechanic tomorrow. If he's still having a problem I'll mention some of the suggestions you've been kind enough to make. This is my third Model A. I had my other two for a total of about eighteen years and never had a problem with either. About all I ever did was put gas in the tank. I guess this kind of problem was bound to happen sooner or later. I just hope all the work my mechanic has helped me with will get me back on the road soon with a long happy future ahead.

[MCHinson]

Turning the engine with the crank did not harm your timing gear. If he was having trouble with the Model A Ford's timing, the timing gear was probably already in need of being replaced.

 

It has been more than a decade since I owned a Model A Ford, and they seem to be a bit more expensive than I remember but a new timing gear is readily available and easy to change. 

https://www.brattons.com/LAMINATED-STANDARD-TIMING-GEAR/productinfo/8750/

[viv w]

Original model A timing gears were made completely of fibre, but some aftermarket ones were made of alluminum . I found an aftermarket one on a worn model a motor, it was fibre and had a splined hub pressed into the centre of the fibre gear, this one had come loose on the splines and was so worn that the timing was all over the place, up to about 10 degrees.

 Generally fibre timing gears are like modern timing belts, it is best to change them at or before 50k miles.

[F&J]

2 hours ago, KenJT said:

He ended up asking me for the crank, thinking (I guess) that he could slowly turn the crank to help fix the timing.

Nobody mentioned exactly "why" the mechanic needed the hand crank.  He was doing the Ford factory suggested timing testing correctly, so this sucks to hear that you wonder if he broke something.  Geez.

 

On that Ford A engine, to "properly" set timing, you must remove the special long pointer bolt which is the "timing tool", that is sticking out of the timing cover (pointing forward, towards the radiator).  Then turn the timing bolt around backwards to have the long rounded end tip fit back into the hole.... Then rotate the engine very slowly by hand crank until you feel that tool slightly drop into the timing "divot" in the timing gear.   If that fiber cam gear has spun a bit on it's metal hub or teeth nearly worn off, then he sees proof of that failure when the tool hits that divot, and he sees that the #1 piston is not really at 100% top dead center by looking in the spark plug hole. 

 

most people set the Model A timing by adjusting the point cam in the distributor (which is how it's done), but they never think to see of the piston is at TDC as I just described above.  They may have used that timing bolt tool to 'find' TDC, but then failed to check where the #1 piston is when the timing divot is felt by hand. They have only assumed that the cam gear is OK instead.

 

I typed too slow, and viv w also backs up the fact that fiber gears can be loose on the hub.

[JV Puleo]

If that is the original gear, it's surprising it lasted so long. Back in the 70's we had problems with Volvo fiber gears...and that was on cars that were, at most, 8 or 10 years old. It was a commonplace to change it if you had to take the engine apart. As the others have said, turning the car with the crank had nothing to do with failure of the gear.

[Mark Gregush]

Some were laminated, they normally are pretty good. Others were macerated (chopped short fiber) very prone to loosing teeth. Then there are the ones that could be made of either material but have a steel or aluminum center, those are well known to give out. 

 

[KenJT]

9 hours ago, pkhammer said:

  Using the hand crank won't hurt the timing gear. The laminated (fiber) timing gear is what I assume he is talking about and like any mechanical part can fail. Perhaps it wasn't getting oil for some reason? I doubt that this engine has gone untouched for 90 years but I assume it's possible. In any case it's easy to inspect. Just remove the timing gear cover from the side of the block toward the front of the engine. Four bolts (two in the block, two in the front cover) and the cover will come right off exposing the timing gear.

  To set the timing on a Model A it's best to find TDC for #1 cylinder then make sure the points are set in the "just ready" to open position on the little cam in the distributor. It can be rotated easily by loosening the screw in the center directly under the rotor button. A special wrench to hold the cam while the the screw is being loosened and tightened will be necessary. The rotor button obviously needs to be pointing toward firing the #1 spark plug. Make sure the timing lever on the steering column is in the "up" position or maybe one notch down.

I was just rereading the replies to my question. After reading your reply I'd like to ask you another question. You say that the timing gear is easy to expose so that it can be checked. My mechanic told me that in order to replace the gear he had to remove the radiator and other related parts. Clearly this is a much bigger job than just removing the timing gear cover. Can you tell me if my mechanic is right? Obviously he'll be charging me for a much bigger job than removing the cover if that would have allowed me to change the gear. 

Edited June 6, 2022 by KenJT (see edit history)

[Mark Gregush]

You don't have to remove the radiator/hood but would make it easier. I have replaced one with it still in place. The front of the engine has to be supported. Yoke/generator removed. Then remove the timing cover/side cover. Make sure the pan bolts are out. Break the nut free and remove, it's tight. Remove timing gear and make sure the timing marks are lined up when installing new one. Replace the rope seal in cover, install gaskets and reinstall parts. Hope no bits and pieces fell in the pan. Think the one I did, had two blade fan, don't know if 4 blade would be in the way. 

[Dave39MD]

You should probably go to the shop and let him explain it so you can see what he is talking about.

 

Dave

Edited June 6, 2022 by Dave39MD (see edit history)

[dictator27]

With all due respect to you sir, you are making.a mountain out of a molehill.  A model A has to be one of the simplest vehicles there is to work on.  Removing the radiator is not a big job and will make accessing the timing gears much easier.  All the advice given here is spot on.  If that is the original fibre timing gear it has done well to last 90 years.  

[Rusty_OToole]

Have heard of certain cars (not Ford) where the manufacturer changed the fibre gear to metal and rivetted a leather or fibre ring to the gear to damp out noise.

[pkhammer]

Removing the radiator makes accessing the front of the engine much easier. It's an easy job to INSPECT the timing gear without doing all of that but to REPLACE the timing gear it makes the job much easier.

[Mark Gregush]

But if you are paying someone by the hour....

[JimKB1MCV]

"But if you are paying someone by the hour...."

 

  Well, if you have to pay someone by the hour its a pretty good argument for getting a set of tools and a manual for the car.

 

  Just sayin'...

 

 

[Bhigdog]

3 hours ago, JimKB1MCV said:

"But if you are paying someone by the hour...."

 

  Well, if you have to pay someone by the hour its a pretty good argument for getting a set of tools and a manual for the car.

 

  Just sayin'...

 

 

There's some folks that pay by the hour to have their lawn cut........Just sayin..........Bob

[JACK M]

I would bet that taking the radiator out of the mix would save time in the long run and might even save denting the thing up.

Kind of like taking out a front seat to do under dash work. Usually only takes a few minutes and makes the job so much more comfortable.