MTFCA Forum

Has anyone installed one of these ? How did you determine you needed to shim your crankshaft ? to How did you machine yours to obtain the proper thickness ? Many thanks!!

Measuring how much end play you have is how you begin to determine if something needs to be done about it. I guess I wouldn't want to see more than maybe .015"/.020", but then I don't run a magneto, so it's not as critical. Other opinions may/will vary. Some engines will run well with lots more end play than that, but at some point, if you have your magneto installed, the magnet plates will begin to rub on the field coil posts, or the gap between the magnets and the field will become too great and you'll lose mag output. Both conditions are bad news. There's other ramifications as well, but that's enough for now.

A shim, in this case, is a bandage. I can't comment on the shim you have in mind since there were a few different varieties over the years. It's better to replace & refit the rear main bearing, which is where end play is controlled.

It's a good thing that I don't have a magneto because I have .045" of end play. I bought one of the shims to get me through the summer and I will address the rear main in the fall. I have not machined my shim yet but I have access to a Bridgeport mill for that purpose.

John, I re-read your magneto thread ( https://www.mtfca.com/phpBB3/viewtopic. ... 541#p61541 ) from last fall. While it's quite possible that the rear main wasn't fitted properly and has worn to the extent that you have excessive crankshaft end play in a relatively short period of time/miles, I would expect that extra end play to primarily occur in the "magneto gap getting larger" direction than "magneto gap getting smaller" direction. I agree with Jerry that 0.020" is about the most I'd want to see, and I'd add that the magneto should work up to that value, as well. You originally reported the magneto "cutting" in and out, so I don't really suspect end play to be the only problem, although it would certainly exacerbate it. At the upcoming KC Chuggers shop day, we can check the end play, along with the mag output (again, as you've already done it), wiring, switch, etc. prior to doing an in-car recharge if you desire. The recharge won't permanently help if there's a wiring or switch problem that will subsequently scramble the magnets, which is part of why we should check those things, as well. If the end play is ridiculous, there's no need to proceed with an in-car recharge, as the magnets would still not be able to overcome the inverse square law with an excessive gap.

Having written all that, I realize that wasn't the point of your original post - there are different shim methods (from pulley rubbers to rear main shims), but all are basically a bandaid. There are a few ways to measure end play, and as stated above, I'd try to stay below 0.020" or so. Pulling the brake lever back will move the crank one way, and throwing it forward into high will allow the crank to be able to be pried (gently) the other way. However you check end play, be sure to do this, or you won't get the full value.

I know guys that have built up the cap thrust face with solder. Seemed to work OK

I have used the brass shim that fits behind the crankshaft pulley. It lasted a bit over a year with a fair amount of driving. It was supposed to be a short term fix until I could pull the engine but I replaced it with another one after the first one wore down and got another year plus of driving out of the second one. I finally rebuilt the engine but I am convinced that I could have continued running with those shims indefinitely.

In Tinkering Tips a guy had excessive crankshaft end play in a 14 Touring he was going to drive on a Tour. It was enough endplay to cause the car to misfire and run poorly on Mag.
He came up with a quick fix and it worked pretty well.
He removed the end cap, used a round file and elongated the cap holes enough so the cap could be moved closer for less end play.
He flattened some nails to put between the bolt and the cap holes so the cap would stay securely in the closer position.
He completed the tour OK and drove the car for a good while after until he decided to fix it correctly.
I guess you could call that a farm fix! But it did work.

I remember that Tip. Not all tips were good tips, nor really recommended by today's sensibilities. That fix ruined another main bearing cap for the sake of a tour, plus, it didn't take out ANY endshake, it just moved the magnets perilously close to the flywheel. Things flapped around as much as they did prior to the "fix", just with potentially increased risk of disaster. I personally would not recommend other than to know about it for curiosity's sake.

Several years ago Ken Foster worked with Steve Coniff, John Regan and I to correct an excessive crankshaft end play on his Model T.
Ken is a detail person, was careful to document the process for posterity and wrote a great article about the process. Here is a link: http://www.funprojects.com/pdf/Excessiv ... Repair.pdf
It takes time and patience, but this process works great.
Ron Patterson

Oops.
I forgot to mention, Kens procedure is a permanent solution for the problem, not a short term patched up fix.
Ron Patterson

That was a great article, written by a guy who has a lot of patience!

I just tore an engine down that had one on the front of the engine between the lower pulley and timing cover, it was brass, bronze? and adjustable, I have seen them before and I know Tim Morsher repop some then Snyder's carries them now in the book. It is a quick and inexpensive fix that will work to get you mag back in clearance.

HOLY SMOKE, Guys!!! I believe either me or my kids can someday contract for a complete rebuild and enjoy a proper fix then. Until then I think I'll just drive her on battery and be thankful for a sweet running Lizzie. As always, THANK YOU, THANK YOU, THANK YOU, for your invaluable input.

Joe Bell wrote: ↑

Fri Feb 14, 2020 6:32 pm

... It is a quick and inexpensive fix that will work to get your mag back in clearance.

Controlling end play also reduces damaging movement in connecting rod bushings.

Mark, I pour and line bore all the time but if some one wants a quick fix this works, my self tear it down and go through it.

Rather than use solder to build up the thrust face, I have used soldering techniques to add whitemetal. This can be a permanent fix, provided the thrust face on the crankshaft is not undercut with wear. Either way, if the added material is worked back so the cap is a neat fit, any such wear will give some running clearance.

Allan from down under.