MTFCA Forum

As mentioned in a previous thread, I found a couple of brass screw heads in the drain plug while changing the oil and what I suspected has been confirmed. I pulled the starter and found one of the magnet retainer clips resting on the pan ledge next to the starter. So, the next logical step was to remove the hogshead and do some further investigation. The pictures show that three of the magnet clips have let go and are inside the oil pan. looks like it is time for engine removal and tear down. What started out as a reasonably priced '24 roadster project just got a bit more expensive.

Any suggestions as to why the brass screw let go? Maybe excessive crankshaft end play caused the flywheel to touch the field coil? Or is it simple metal fatigue after nearly 100 years?

Don't bother pulling just the hogs head, pull the whole bloody engine, your going to have to drop the pan and remove the transmission anyway to replace that plate, might as well check the magnets whilst you're at it also (I set mine to pick up a 4 lb wrench). also when you're setting you level on the magnets, don't use a steel hammer to smack them down .001 or .002, because it can (and will) weaken you magnets, if you've got to hit them to level them use either a plastic coated dead blow like you can get at Harbor Freight) or use a brass hammer, neither one of those will transfer magnetism, but a steel hammer will.

Happened to me too, only I had two plates bouncing around within the crankcase. When they initially let go there was a loud bang and one of them put a dent in the bottom of my oil pan inspection cover, even so I ran the car for 4 more years until somebody convinced me that it was a ticking time bomb.

Sometimes those screws have defects in them (don't use them if they do, I had to buy two sets to make sure I got good ones...of course I was weighing the all too, if I found one that was off by a few grams I switched it out for one that was closer to what I set as the mean) and sometimes somebody somewhere used the old ones over (which was my problem).

Have you checked your runout lately? the magnets look like they're traveling a bit too close to the coils...older rebuilds use to set to the bare minimum tolerance (.022) rather than (.024 or .025) which still gives you a killer magneto, but with enough clearance for a little slop in the runout.

I'm right there with you.

I found two magnet keepers and screw heads in the oil pan when I pulled my engine apart. I found that there was excessive play due to a worn rear main bearing. Once I had it apart, I could see where the field coils were starting to rub against the magnet keepers. I sent the bearing to Gene French for rebabbitting. He used my end play measurement to properly oversize the babbitt to give me a very snug rear bearing. That is now back and installed on the engine.

I'm now replacing all of the magnet screws and checking the magnets to see if any are broken.

They let go because they're 95 years old and are brass.

The last one I did had 4 broken screws and when I went to remove the others after filing off the peined-over ends, 4 more broke off at the very slightest torque of the screwdriver. I believe I could have popped the heads off if I simply had pried the keeper with my fingers...there was only a tiny shiny area on the brass as they had actually cracked/broken years before and had somehow not finished parting ways with the body of the screw.

Now is a good time to look hard at the starter ring gear as well, and decide if it wouldn't be cheap insurance to replace it at the same time.

You have now joined the "club" of people who simply EXPECT to have to pull an engine from a newly purchased non-restored Model T. Particularly if it is a "Ran when parked" Special.

And when you level the magnets at reassembly, invest in all new aluminum spools and do not hit ANY magnets to level. RAISE the magnets with spacers. Excellent premade spacers of the correct size and of varying thicknesses can be purchased from McMaster-Carr.

I appreciate the input, it always helps to have insight into what fellow T drivers have experienced. I really shouldn't be surprised that the transmission would have this problem and should expect to find something else that needs attention. I have worked on T's since I was a teenager know that a lot of things can and will break. This will be an opportunity to correct any of the other unknowns inside the engine.
I will post updates on the progress. Our forum is a great resource.
Thanks for the replies!
RB

...do not hit ANY magnets to level. RAISE the magnets with spacers.

As the geologists would say, my sediments exactly. I despise the notion of banging on magnets with any kind of hammer. It never occurred to me that ready-made shims were available to raise the low magnets, so I made my own.

What if they sit too high? Then it isn't a matter of shimming them, it is to lower them and you've got to smack them a bit. My point is don't use a steel hammer, use a dead blow instead, preferably a plastic encased one.