Would you run this Main?

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Model T Ford Forum: Forum 2017: Would you run this Main?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Instness on Thursday, May 11, 2017 - 04:26 am:

Cleaning up a spare motor to have on hand and potentially run for a few months in the event that either motor in my 2 Ts ever need to come out for a full rebuild. Was hoping to avoid having the babbit redone being this is just a spare motor. After pulling the crank I discovered a chip in the corner of the front main babbit. Would you run this?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Thursday, May 11, 2017 - 05:04 am:

Rather not, but I'd be less worried with such a chip out of a main bearing than if it's missing on a rod - that would be a big no no.
I think this might hold up for some months - with a good oil supply, of course.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Thursday, May 11, 2017 - 05:17 am:

If the bearing fits well and the rest of babbit is tight to the block, I would have no concern. Consider that Ford didn't babbit the blocks of the early T engines at all , just the main caps. There is very little vertical up main bearing load on the front main bearing


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chad Marchees _____Tax Capital, NY on Thursday, May 11, 2017 - 05:56 am:

If it's good babbit, and it fits well and not worn out, I'd run it.

The other choice might be that Gene French in the classifieds is offering rebabbited main caps with no exchange. Its not necessarily the best way to go (ideally you want the cap and block line bored together) but it defiantly is an inexpensive way out if you take the time to fit it and the babbit in the block is in good condition.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank van Ekeren (Australia) on Thursday, May 11, 2017 - 07:38 am:

If you are going to take a chance on it, at least chamfer the edge off it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By john kuehn on Thursday, May 11, 2017 - 09:14 am:

That has happened more than we think to engines that have babbit mains I'll bet. And they ran that way and people didn't realize it for no telling how long.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robin Pharis on Thursday, May 11, 2017 - 09:56 am:

Chris bring the block to me. I'll take care of it for you.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James J. Lyons III - West Virginia on Thursday, May 11, 2017 - 10:19 am:

The chip is not a concern.... the babbitt being tight to the block IS. spray the babbitt edges liberally with carb cleaner and let it sit for 30 seconds or so. Then, with your fingers, press on all areas of the bearing surface. It the babbitt is loose, you'll see oily carb cleaner squeeze out of the edges as you press.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Thursday, May 11, 2017 - 07:58 pm:

What is the matter with you guys? It is MY job to say "yeah sure, I'd run it!" You are supposed to say "not a good idea" or "better get that fixed right".
The Babbitt can almost always be pealed out of the block because it doesn't stick that well into that grade of cast iron. SOMETIMES and generally only by the best of the re-Babbitters, it can be bonded really well. That is why there are holes in the cast iron main bearing beds to hold the Babbitt into place. Caps are made out of a different alloy that bonds better. If the Babbitt is loose in a cap, THAT is a problem.

A chip like that is not a good thing. If you want a top rate long term engine? The job should be done right!
For a temporary/spare engine? Yeah. I wouldn't worry about it.

Also, I would worry more if it were a center main. It is a little under size for the amount of stress it takes, and any loss of bearing surface area can result in the surrounding Babbitt hammering down and enlarging the lack of support.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Barker - Dayton, OH on Thursday, May 11, 2017 - 08:20 pm:

Why not fix it right while you have the perfect opportunity? You don't need the engine right away so there's no time pressure to get it done and ready to run as soon as possible. Repair it right while you have the chance now. The peace of mind knowing it's in good condition when you're putting this engine in a car that needs it would be worth it in the long run. Just my opinion, of course.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Nevada Bob Middleton on Thursday, May 11, 2017 - 09:34 pm:

I run something simular never had an issue


Top of pagePrevious messageNext messageBottom of page Link to this message  By Nevada Bob Middleton on Thursday, May 11, 2017 - 09:34 pm:

I run something simular never had an issue


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve McClelland on Thursday, May 11, 2017 - 11:48 pm:

While you have it in your hand is a perfect time to change it out I looked I don't have a spare or I'd send you a better one to go back in. Surely someone on here can help you avoid a future issue by putting back in a cracked main.


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