MTFCA Forum

Question for the T bunch- my 1915 is fighting me on the timer lever; when I am running the car the fan belt is resisting my advancing of the timer.

When I advance the timing and let go, the fan belt pushes the lever back up. I am running a size up from the standard 23" for 1915 and my car has the aluminum fan pulley, I tried putting on a standard 23" and it is too tight. Won't work- any solutions?

Thanks,
Jim

Jim

somewhere in your fan assembly, it is running too close to the engine (timer). If the crown is worn off the pulley, that will do it. Also, I have had to place a shim between the block and fan bracket; once had to add a spacer between the fan bracket and the fan; and once, the fan bracket was bent back a little and that caused the belt to track too far back on the crank pulley.

If you've ever had to align flat belt machinery, you may recall that the relative fore/aft location of drive pully vs driven pulley can make a difference, as well as skewing the axis of drive pulley vs driven pulley. Both of those create havoc on keeping belts on machinery and the T engine is no different.

I would expect, in this order:

1. aluminum pulley has no crown and belt wanders its track
2. aluminum pulley is too far "aft" relative to the crank pulley
3. fan arm bent (tilted) forward a little (belts want to ride up to the tightest position, and tilted forward would make the fan pulley act "larger" toward the rear).

When everything is right, the belt should just barely clear the timer

I would try turning your fan bracket around. You have it now where it sits a bit closer to the engine. You’ll have to take the pulley off and then you can turn it over where it will sit a little bit further away. Might still need a shim but maybe not.

For a '15, I don't see anything that is correct! You might try putting the correct parts on your car, and getting rid of that aluminum crank pulley!

You can't turn the fan bracket around, the adjusting tab would be on the wrong side.

I can't tell from the picture, but is your fan bracket straight like the 17-25 ones, or does it have a bend near the top? It should have the bend near the top for the brass radiator cars. Look in the Lang's catalog for a good picture of each.
Ralph

Mark Gregush wrote: ↑

Sat May 25, 2019 10:03 pm

You can't turn the fan bracket around, the adjusting tab would be on the wrong side.

LOL *smacks forehead* duh, yeah. What Mark said. Just do like I did and take the fan off completely. I have an electric one I only run if I’m gonna be sitting still idling for a long time. Or going slowly up a hill. Then you don’t have to worry about it ever slinging a blade into your radiator.

Thank you for the suggestions. I do want to keep the fan I like the stock look and it belongs on the motor. It also is not bent so I have a later fan bracket – thanks for seeing that.

I will replace the fan bracket and go from there – thanks guys!

May be as easy as bending the warped timer rod away from the belt, or move those washers at the cotter pin end to the backside of the timer tab to push the rod back.

Your pan is later and you could install the larger crank pulley for these later pans, that way the current fan assembly you have will work with correct belt, longer belt will ride more straight up and place the center of the fan higher up the radiator face as needed. Seems now your fan blades ride a bit close to the crank handle shaft.

Thanks Dan, I'll start there. I appreciate the tips and sometimes the simplest answer eludes us, that's why I value this forum.

You say "I do want to keep the fan I like the stock look and it belongs on the motor."
I am not sure what "stock look" you are wanting to maintain, but that fan hub was not "stock" until at least 1919. The larger fan hub on it is the main reason why you cannot fit the one inch smaller belt. Also, the longer arm severely limits fan belt adjustment if your '15 has a '15 style radiator. The top tank of the earlier radiator is lower, and even the side is narrower (only very slightly) than the black era radiators. With the longer arm, you cannot bring the fan near the proper top adjustment, nor the lowest adjustment. I made one work once many years ago, but it just barely worked.

Just out of curiosity. What is the year of the motor? Its manufacture year does not really matter. But another thing that does really matter, is having proper pulleys to have proper fan speeds. A small bottom (crank) pulley with a large (later) fan pulley will result in a slow fan, making the fan less useful than they already are. A fan on a model T is basically useless anyway. I (and MANY others here) have run Ts for many miles without a fan, or simply no belt. At usual driving speeds, basically anything over about fifteen miles per hour, the fan contributes almost nothing to the cooling of the motor (with rare exceptions for a perfectly matching tail wind).
Worse yet, is a large bottom pulley with an earlier (small) fan pulley. This is not what you show, just for advisement purposes. The larger crank pulley runs the small fan pulley TOO fast. Model T fan blades break and severely damage radiators often enough when things are more or less correct. Basic engineering theory says that if you double the fan's speed, you quadruple the likelihood of breakage from vibration and other forces. (Those are round theoretical numbers, not precise figures.)

My motor is a 1916 block. I shimmed the fan arm and ordered a more correct bent earlier style. Looks like it'll do the trick.