Fourth Main Woes

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Model T Ford Forum: Forum 2015: Fourth Main Woes
Top of pagePrevious messageNext messageBottom of page Link to this message  By Nathan Fahrni on Monday, April 13, 2015 - 08:40 pm:

Is there anybody who can pour a custom diameter fourth main? I have an engine in my T that has had the tail shaft turned down to 1.500" (NOT BY ME!!!) I first discovered the issue when I kept losing engine oil to the rear axle and that the aftermarket needle bearing fourth main leaks like a sieve. According to the vendors' catalogs, the standard size of the output shaft is 1.560" and fourth mains are available up to .010" undersize. I need one that is .060" undersize. I'd really hate to have to pull the engine out and clear down to put a new tail shaft in it. Hopefully there is somebody out there that can help! If I can get my hands on one I'm not afraid to scrape it down and fit it, sure beats pulling the engine. I also plan on calling the T vendors tomorrow to see if their supplier/s can make me a custom poured 4th.
Thanks,
Nathan


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett - Australia on Monday, April 13, 2015 - 08:58 pm:

Nathan, perhaps the shaft has been turned down to accommodate one of the ball bearing fourth mains which have been offered over the years. If so, and you can find a replacement with a fully sealed bearing, it might just be a simple replacement job.

Otherwise, I have freshly poured bearing caps which are un-machined, ready for use when needed. Whether they have enough material to be machined to 1.5" I would have to check. If you have no success getting what you want, I could post one to you, machined to size.

Hope this helps.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Walker, NW AR on Monday, April 13, 2015 - 09:05 pm:

Nathan -- Ron's Machine shop in Shandon, Ohio rebabbits the 4th mains sold through all the vendors. They will make one any size you want.

http://www.ronsmachineshop.net/


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Bender Tulsa Oklahoma on Monday, April 13, 2015 - 09:10 pm:

The drive plate shaft was ground smooth, "bearing surface".

I would bet the finish on the turned down portion will not be smooth enough and the fourth main will not last.

Yes I could pour one that size but it really will be a waste of both of our time.

Why not put another 1.5" type fourth main with modern bearing. The bearing is sealed.

My 2 cents worth, I am not a fan of the modern fourth main.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Nathan Fahrni on Monday, April 13, 2015 - 09:37 pm:

The tail shaft bearing surface is very smooth for being turned down. I didn't even realize that is was machined until I really looked and noticed the step since it is flush with where the clutch spring cup rides. The current aftermarket bearing fourth mains won't work because my driveshaft bell is not modified and I will not cut 3/8" off of my driveshaft, that will be just as bad as turning down the tail shaft in my book. I'm not sure where this needle bearing fourth main originated from. It looks just like a standard babbit fourth main except that it has a thin cage like needle bearing in it. It doesn't interfere with the driveshaft at all, just won't hold oil unfortunately .I'll call Ron's machine shop tomorrow.
Thanks,
Nathan


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Monday, April 13, 2015 - 10:51 pm:

Ball cap bearings are not sealed, they are only shielded. A sealed bearing, add's a lot to the price.

We are the only ones making a ball cap with a 1.500 bearing I.D., and you don't have to butcher the driveshaft tube ball.

But, we only sell to machine shops, as the tail shaft has to be cut with the right amount of clearance, and straight with the center line, and you can't do that by just holding the tail shaft in a head stock.

Herm.






Top of pagePrevious messageNext messageBottom of page Link to this message  By Dean Yoder, Iowa City IA. on Monday, April 13, 2015 - 11:04 pm:

Nathan, I sent you a PM


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Huson, Berthoud, Co. on Tuesday, April 14, 2015 - 12:47 am:

Nathon: If Kohnke does it, it is RIGHT. Another easy cure would be a different clutch plate that has not been ground down. Gene French will also pore you new babbit but will need your clutch plate.

picture


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kenneth W DeLong on Tuesday, April 14, 2015 - 10:47 am:

[A sealed bearing add's a lot to the price] A broken crankshaft is more expensive!!!!!!!!!!!!!!!!! Bud in Wheeler,Mi.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Tuesday, April 14, 2015 - 12:38 pm:

Your right Kenneth, a bent pan will do it every time, along with a bad center line from the front of the crank, to the end of the tail shaft.!!!!!!!!!!!!!!!!!

Herm.


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