To thrust or not to thrust the block?

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Dave1
Posts: 83
Joined: Sat Jan 12, 2019 12:01 pm
First Name: Dave
Last Name: Eddie
* REQUIRED* Type and Year of Model Ts owned: 1926 Tudor, 1926 Touring, 1931 Plymouth PA, 1952 Hudson Hornet
Location: Lillooet BC. Canada

To thrust or not to thrust the block?

Post by Dave1 » Fri Dec 22, 2023 11:46 am

I realize this is a bit of a contentious topic, but I would like to put it out there just the same.
Question is, whether to add Babbitt to the sides of the rear main bearing saddle on the upper (block) side. One school of thought argument against is that in order to get the Babbitt to stick you should tin the cast iron. Because this area is oil soaked removing the oil from the cast icon is difficult if not impossible.

However in this case I have align bored the main bearings out to accommodate a large Chevy crankshaft. Along with the larger diameter the bearing width has been reduced which means cutting faces of the saddle. This obviously exposes fresh cut cast iron, which I would think? Help the tinning operation.
One of the negatives will be that in the process of boring out the bearing bores the area of the thrust contact is also reduced.
Wondering what had been done in the past, and what were the results?
Trying hard to no re invent the wheel on this project,

Dave


Erik Barrett
Posts: 531
Joined: Mon Jan 07, 2019 12:32 am
First Name: Erik
Last Name: Barrett
* REQUIRED* Type and Year of Model Ts owned: 1913 speedster 1924 touring 1925 dump truck
Location: Auburn, Ca.

Re: To thrust or not to thrust the block?

Post by Erik Barrett » Fri Dec 22, 2023 1:30 pm

Don’t bother with thrusts on the block. The best thing you can do is put a bronze thrust bearing on the front of the rear cap. Permanent solution.

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Mark Gregush
Posts: 5370
Joined: Sat Jan 05, 2019 1:57 pm
First Name: Mark
Last Name: Gregush
* REQUIRED* Type and Year of Model Ts owned: 1925 cutdown PU, 1948 F2 Ford flat head 6 pickup 3 speed
Location: Portland Or
Board Member Since: 1999

Re: To thrust or not to thrust the block?

Post by Mark Gregush » Fri Dec 22, 2023 3:50 pm

If you are going to add thrust babbitt to the block too couple of way you could do it. Angle the face back top to bottom to lock the babbitt and/or drill anchor holes like the saddle for a mechanical lock.
I know the voices aren't real but damn they have some good ideas! :shock:

1925 Cut down pickup
1948 Ford F2 pickup

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