Excessive crank end float.

For the amount of money it would cost to weld/regrind the crank (and the time to drag it around) - I'm sure you could find either another crank and/or try the "iron a bearing fix". I like my crankshaft thrust to be between .004 and .006 inches.
 
Mart said:
Crank is low miles French military rebuild. Bearings are brand new. Saddle is not worn.

I think the French military might have ground the cranks oversize on the thrust faces and had access to oversize bearings to suit.

I have a crank with a damaged thrust face. Can someone give details on the welding process to build up the thrust face?

For example, what type of welding? Mig? Arc/ what type of wire or rod? Special gas?

If normal mig welding and wire I could try myself. Ditto if arc if I know what rods to use.

Thanks for the input so far..

Mart.
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Crank welding is done in a crank welding machine by the submerged arc method. Basically it is an automated wire feed type where the actual arc area is submerged in a special granular powder while welding.
Pre-heat and controlled cooling are part of the process.
 
I ran the engine for a few miles but have yanked it out as it does not seem happy. I'll have to look at it in more detail when time permits. Installing a plodder motor for the event this weekend.

I will look at adding babbit / white metal. I have no knowledge about it though.
 
Mart, A talented man such as yourself will have absolutely no trouble building up the thrust faces. As I mentioned above, use a big soldering iron [more control that using a torch]; you don't want to damage the existing bearing material that the journal runs on. I use 'Fluxite' paste [made in England, so you should be able to source it easily], NOT an acid based flux [spirits of salts etc]. It'll build up real easy; like, the faces are already tinned for all accounts. Practice on an old bearing first? Good luck!
 
Good advice Brian. An old guy in my model T club does this with the babet thrust on the poured babet to save an otherwise good engine. Finishes the face with a home made gizmo like a line boring tool
 
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Brian said:
Mart, What I've done a coupla times now is to build up the faces on the bearing. use a big iron and some whitemetal. easy peasy; the faces are already 'tinned' so to speak, just need a bit more of a build up each side.
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Is Whitemetal another name for Babbitt? Would you just melt a blob off a bar with the iron or can Babbitt wire be purchased? I don't have babbitt scraps, only a couple bars of new material here of unknown providence.
 
I think babbit and white metal are much the same thing. Just a lead/tin alloy. I think different grades are available, but I just use what I can find 'unknown providence'. I find it cast as ingots, normally it is melted in a pot and poured into a mold, but you can melt some off the ingot with the iron and apply. Basically, it is just like solder....
 
Sorry Mart, to buy one ingot from that site will cost 53.12 Pounds? WR89A (BS3332/A) is their code for babbit. The stuff is available, ask around, someone into the repair etc of vintage cars should be able to furnish some. Good luck!
 
Thanks Brian, I just got off the phone with another supplier, he will get me what I need. Thanks for the guidance.

Mart.
 
Mart, I had this same problem with a French motor. When the motor was being reassembled we noticed the excessive end float and came to a stop. I sold the engine to Jim T and told him about the problem before we finalised the deal. I believe it is not uncommon on these motors and Jim has a solution to it.
Give Jim a call and see if he can put you straight.
 
It sounds to me like they must have had a different (wider) rear main bearing in these French motors - especially since you said the crank is in great shape with no outward sign of thrust surface wear. I wonder if you can locate a new rear main bearing - the 'French Flathead width'?
 
Dale raises an interesting point...Ford also provided rear main bearings with oversized thrust faces. The only listing for such in my Canadian catalogue is #81A 6331T which is .015 os on thrust faces, but .030 us on journal.
 
Just a little input on this very interesting problem Mart.
I like the idea of building up the thrust surface of the bearing to restore the proper thrust, but I would do it a little differently. With your skills and tools you should have no problem using solder to attach a brass shim to the thrust surface, and machine as necessary. Tin the brass shim prior to soldering.
I personally feel the end result will guarantee a more durable fix.
 
Deuce5window.....The way the bearing fits the saddle would require the bearing thrust to be bent outward and then machined parallel to the crank thrust surface. I dont like the need to make the shim to properly backup the bearing thrust. Have i lost you........?
 
Crazy question if you can't find an org thrust bearing that has the thicker thrust surface, if you have to do something to the bearing you have would it be best to do the work on the front side that it will just have normal thrust load and not the back where it has clutch pressure against it?
Steve
 
STEVE O said:
Crazy question if you can't find an org thrust bearing that has the thicker thrust surface, if you have to do something to the bearing you have would it be best to do the work on the front side that it will just have normal thrust load and not the back where it has clutch pressure against it?
Steve
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Absolutely correct. The .015" or so that Mart needs would cause no problem if done as you suggest. :)



Terry
 
Russ/40 said:
Deuce5window.....The way the bearing fits the saddle would require the bearing thrust to be bent outward and then machined parallel to the crank thrust surface. I dont like the need to make the shim to properly backup the bearing thrust. Have i lost you........?
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No Russ, you didn't lose me (yet lol) but we are only talking .007 on each side and as far as straightening the side it could be done on a flat surface with sandpaper after the sides are forced out by the shims. Just tossing out an idea.
 
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