Lesser of two evils..cracked main babbit or used replacement?

[Nosetime]

Gentleman, I need some experienced engine builder advice. Save the "rebuild it", I know what is best practice, but I need to get some miles out of this engine before a complete rebuild. I posted my question a while back and some of the best here agreed to just run it, without to high of expectations. But, this weekend I bought 3 rear mains with one that has good babbitt...for $5. It looks like shelf wear scratches and very solid. I did not clean it up so the pics are as found. It appears to fit the crank very well, so my question. Would you try and use this instead of the cracked one? My thought is to assemble with prussian blue or something, Give it a few turns..carefully fit, then spec carefully on assembly. I assume this has been done before?

[Kurt in NJ]

Ford sold pre finished caps, fit it and put it together

[Nosetime]

Kurt, any advice on the fitment? BTW, I noticed the picture makes it look worse than it is. I will be thrilled if it works, as the rest of my engine is looking pretty good. Thanks, Greg

[Bill Pursel]

you need to keep in mind that the crank main could be std. .010,.020,.030 or more so replacment main cap needs to be the same.

[Synchro909]

Originally Posted by Bill Pursel

you need to keep in mind that the crank main could be std. .010,.020,.030 or more so replacment main cap needs to be the same.

Those are the standard sizes for undersized inserts. For babbit, they can be anything. One of the things I like about babbit is that a reconditioner can grind the shaft just enough to clean it up, then bore the babbit to suit. Only the bare minimum is removed from the journals. If the cap the OP has is an originall Ford replacement, what you say may be correct but otherwise, there is a good chance it is not.

[Nosetime]

Sponsored Links (Register now to hide all advertisements)

Yes, Bill I thought the same thing. But, would the proper original that is broken, be better than a "close enough" replacement? Again, my expectations would be realistic either way. Would there be a way to spec out what I have to help the decision? I'm runnin' one or the other either way.

[Tom Wesenberg]

I'd also fit it and run it. Shim to get .0015" clearance. If the diameter is correct, then you shouldn't be able to move the main left and right against the block more than .0015". If you can move it 10 or 20 thousandths, then you need to find a better fitting main cap.

[zzlegend]

Greg, you did not mention if you have shims on that main, but why not install a few shims and then a small piece of plastigage, tighten down the cap and then remove it and check for clearance and repeat with less or more shims if needed. Would not take long. That looks like a nice cap. Just my 2 1/2 cents.

[Ernie Vitucci]

I agree with ZZ...Ernie

[Kevin in NJ]

By fitting, put the crank in and spin. High spots should be shiny chect fit. Bit of an art to know what to do next, but if the crank turns tight and the clearance if good then you need to bring down high spots. I am not very experienced at it so I do not dare go further. Obviously you will playing with shims at the same time to get the fit.

FWIW there are special babbitt scraping tools. You may have to make due with a knife edge.

[Railcarmover]

I dont care for plastigage,especially if your fitting a cap like this..the reading the plastigage gives is too narrow for fitting. Id use aluminum foil,Ford used a red lead compound to read the entire face of the bearings,not just the 1/8" the plastgage reads. Its important to figure out what kind of babbit the caps you are considering to use have.Model T US grade 2 babbit is hard and will take a sharp knife to shape,stock model a babbit is way softer,and easier to shape.

Aluminum foil ,heavy duty folded is about .002,use a mic to set. Cut foil for full width of the bearing shell,install the shell and torque it.remove shell and 'read' the foil.Make a bearing knife and scrape the bearing to fit. Impression fluid like Ford used is good as well,it will tell you where you need to concentrate with the knife..patience is key,cut,fit and check,repeat till you hit the sweet spot.002 to .0025. Grade 2 babbit is harder to dress with a knife,A babbit cuts easy.Take you time,hand fitting babbit takes time and patience,its the method Ford mechanics used.

Its important to do all work using .030 shims,that way when its fitted you get full life out of the bearing..but dont worry if you remove a shim or two to make up for overzealous knife work,it happens.Babbit wears about .001 per ten thousand miles or so,so losing a shim or two fitting will still give good life.So many neglect to properly check and maintain their bearing clearances, with the engine in the car its hard dirty work..but necessary for full engine life.

[ryanheacox]

Originally Posted by Railcarmover

Model T US grade 2 babbit is hard and will take a sharp knife to shape,stock model a babbit is way softer,and easier to shape.

Not to get off topic but why would Ford have used much softer babbit in the Model A?

[Kevin in NJ]

Originally Posted by ryanheacox

Not to get off topic but why would Ford have used much softer babbit in the Model A?

Umm, Ford didn't use softer babbitt then grade 2.

The copper makes it harder and hotter to pour. The 2 stuff is just what is easy to get and works ok. You have to have a large batch made to the Ford spec if you want the original numbers. At least that is what we have found trying to source the correct babbitt for our own cars.

Babbitt grades

[Nosetime]

Well, got my Babbitt tool, what a beautiful piece of art! Then it occurred to me I have the extra main caps to practice on! A few strokes on the stone and my tool was sharp. But, what I did not expect is how enjoyable...read therapeutic or stress relieving to pull a few curls on the babbitt! I really had fun getting the feel of this and am really looking forward to fitting my cap! Thanks to all for the help. BTW, I just ordered a 30-31 Brookville roadster body today. I hope scraping my own rear main babbitt will give me a pass on the new body from the Barn! Ha ha. I just could not do an original body build, but think I am staying true to the spirit of the car. I will do another post later on that whole deal! Greg

[Kohnke Rebabbitting]

Originally Posted by ryanheacox

Not to get off topic but why would Ford have used much softer babbit in the Model A?

Ford used 86-7-7, in his Model T's, A's, and Model B's. If any one has lead in there motor, it has been replaced. During the war, the government had most of the Tin, so bearing builders had to use lead.


If Plastigage does not work for you, its not being used correctly.


Just about all Bearing Manufactures in the U.S. used Grade No.11, Grade 2, and Fords are all right, But Fords is dirty to machine, because of the amount of Antimony used.


Ford said, a 1 inch square of there Babbitt compressed to 14,000 pounds, would only compress, 2%, and that is way over what is needed. The proper clearance for a Model A shaft is .001-60 to not over .002-10


When a bearing has been adjusted down .006 thousandths, it is about time for new Babbitt any way, as the time gears are closer, and after you scrape, is even worse. The rear main will leak more, as the clearance up and down may be right, but the sides will always be standard, or what ever the hole size was when the new Babbitt was put in.


I built 3 engines for a Howard Kittleson in Mn. in the 80's some time. Two Model t's, and one Model A. His 1927 T Roadster went on the AK. tour. There is a lot to tell, but I will make it as short as I can. When he got back, he had 18,000 miles on it and wanted the mains and rods checked. I pulled a.001 shim out of each rod, and stuck the engine, so I had to put them back. Done the same with the mains. He run the car wide open all the time. I told him to use 30 Wt., but he said he used 10-30 Wt., What could I say, NOTHING.


If you have Babbitt that is wearing, better check, and see why. The shaft should not be touching the Babbitt, it should be setting on oil molecule.


I have a few pictures of failed main cap, and showing what happened. I will put the first set on of what a original Ford Babbitt job looks like. The failed caps are of builders, we all know, and love.


Herm.

[40 Deluxe]

Originally Posted by Kohnke Rebabbitting

Ford used 86-7-7, in his Model T's, A's, and Model B's. If any one has lead in there motor, it has been replaced. During the war, the government had most of the Tin, so bearing builders had to use lead.


If Plastigage does not work for you, its not being used correctly.


Just about all Bearing Manufactures in the U.S. used Grade No.11, Grade 2, and Fords are all right, But Fords is dirty to machine, because of the amount of Antimony used.


Ford said, a 1 inch square of there Babbitt compressed to 14,000 pounds, would only compress, 2%, and that is way over what is needed. The proper clearance for a Model A shaft is .001-60 to not over .002-10


When a bearing has been adjusted down .006 thousandths, it is about time for new Babbitt any way, as the time gears are closer, and after you scrape, is even worse. The rear main will leak more, as the clearance up and down may be right, but the sides will always be standard, or what ever the hole size was when the new Babbitt was put in.


I built 3 engines for a Howard Kittleson in Mn. in the 80's some time. Two Model t's, and one Model A. His 1927 T Roadster went on the AK. tour. There is a lot to tell, but I will make it as short as I can. When he got back, he had 18,000 miles on it and wanted the main and rods checked. I pulled a.001 shim out of each rod, and stuck the engine, so I had to put them back. Done the same with the mains. He run the car wide open all the time. I told him to use 30 Wt., but he said he used 10-30 Wt., What could I say, NOTHING.


If you have Babbitt that is wearing, better check, and see why. The shaft should not be touching the shaft, it should be setting on oil molecule.


I have a few pictures of failed main cap, and showing what happened. I will put the first set on of what a original Ford Babbitt job looks like. The failed caps are of builders, we all know, and love.


Herm.

Would that be Howard Kittleson of Blooming Prairie?

[Nosetime]

Thanks to all. The engine is completely disassembled on a stand. Kevon and Rails method is about what we had figured. Thanks for the nicely described instructions! ZZ, yes of course we will shim everything correctly. I am finally at the end of a year of parts collecting, cleaning, fixing and info gathering! We are doing the Tardel rear frame step this week and frame is ready to be blasted/painted and start putting it all back together! The engine is ready to be assembled. I am really happy to have found that main, the broken one would have bugged me everyday, now maybe I can drive it for some time before a complete rebuild.

[Nosetime]

Railcarver. Any suggestion on making the babbitt knife? Thanks, Greg

[Railcarmover]

Hardest steel you can get your hands on..german kitchen knife,wood chisel..Ford mechanics made them out of old files. Sounds like the engine is out on a stand,nice,it makes the work easier.Test your replacement cap first,if its oversize it will be tight at the parting line(edges) so you'll most likely be working the edges first. Here's to hoping you roll a 7 on the comeout,that the cap you scored for 5 bucks fits on the first fit up.DONT FORGET THE SHIMS!!

Once you are done you can polish the babbit and take out micro abrasions with the BACK of a piece of emory cloth.

The biggest part of the job is you,get frustrated? back off,this is time consuming tedious work,I spend time on ergonomics..no hunched over squinting to see stuff..

If all else fails you can run that cracked one,polish it up good,fill the cracks on the thrust with epoxy..if the cracked chunk is still adhered to the cap..

[dlshady]

Scrapers show up on eBay fairly regularly.