OT: removing spun bearing material from crank

[airwoofer]

A friend rents a house on a farm and we ride dirt bikes on the parts they don't plant. There is an old JD 2750 tractor there that the owner will let us bush hog the grass if we get it running. OK, it is locked up and won't break free so off comes the head and the oil pan. A rod bearing spun ion the crank, leaving melted rod bearing on the crank journal. We want to try to shade this thing back together without having to pull the crank out (major hassle on a tractor). My thinking is using some kind of acid to eat away the bearing material and polishing the rod journal as best we can and putting in a new bearing and rebuilt rod.

Any suggestions what to use to dissolve away the bearing material that is welded to the crank?

 

[HemiEd]

Wow, I would have never thought of using a chemical to do that. Interesting approach, very interesting. I will be watching this thread. :read:

I hope it works out for you. I would have been trying to pick it off, and using abrasives.

 

[67Dart273]

I don't know about that but if you can find the oldest mechanic in the area, there USED to be, back in the last century, a crank grinder that could be used "in the car." We of course are talking here of older cars in the '50's and earlier

Here's one in use at the HAMB. This is NOT being used in a car, obviously, but this is the type of machine:

http://www.jalopyjournal.com/forum/showthread.php?t=519872


Here, fixed the darn photo:

 

[waggin]

OMG...I'm gonna sound old fashioned and this ain't pretty....use a file.......one of them old fashioned things with the handle on it.....take your time...keep the file laying flat....be gentle....the bearing material is soft....the crank is harder...when you get it off take a piece of emery paper and run a leather shoe lace around it a few times and then polish the crank journal by pulling on one side or the other of the lace......:yawinkle:

 

[airwoofer]

Wow, I would have never thought of using a chemical to do that. Interesting approach, very interesting. I will be watching this thread. :read:

I hope it works out for you. I would have been trying to pick it off, and using abrasives.

I have used acid to eat the aluminum that gets stuck in a steel lined barrel when a two cycle piston got too hot and siezed , leaving aluminum embedded in the steel. Had to remove it before honing the cylinder for re-use. Just cannot remember what I used. Might have been muriatic acid.

 

[waggin]

muratic acid will eat aluminum...im not sure but I think it will cause rust on the crankshaft pretty quickly

 

[HemiEd]

I have used acid to eat the aluminum that gets stuck in a steel lined barrel when a two cycle piston got too hot and siezed , leaving aluminum embedded in the steel. Had to remove it before honing the cylinder for re-use. Just cannot remember what I used. Might have been muriatic acid.

Now that you mention it, I used muratic acid to get some siezed/swollen from corrosion pistons out of a 440 block a long time ago. Not sure you can still walk into your local hardware and buy some though. I thought I read do to the terrorist crap, they were going to pull the stuff.

 

[67Dart273]

Here's what you do. Saw off the bottom of the rod and clamp it back on the crank. Pull the piston out of that cylinder, and if safe to do so, pull the pushrods for that cylinder.

"A perfectly good X-1 cylinder engine" is the result. Best part is, it will still sound "just like a Deere".

 

[airwoofer]

As soon as that material is off we will be going in and try to polish the journal as best we can. Might use the rod cap as a curved sanding block and emory paper, ending up with very fine grit. Hopefully there will be .010 or .020 or .0303 less diameter cause that is the bearing sizes available.

Will test the muriatic on the rod which also has the bearing welded to it.

Free tractor so don't want to pour a bunch into it. Just want to be able to bush hog around the farm so we can get to the creek and ride our dirt bikes.

 

[airwoofer]

Here's what you do. Saw off the bottom of the rod and clamp it back on the crank. Pull the piston out of that cylinder, and if safe to do so, pull the pushrods for that cylinder.

"A perfectly good X-1 cylinder engine" is the result. Best part is, it will still sound "just like a Deere".

LOL! That is funny. Yeah, sound like the old "poppin John" one banger they used to make. The old guy across the street still uses one to work his garden. A friend had a cyl go bad on a V8 and he drilled a hole in top of the piston and took out the pushrods. Traded in the car.

 

[godfatherofchry]

use a long peice of emry paper about two feet wrap it around the crank pulling it back and forth untell clean.take sum carb cleaner spray it clean.put new bearing on rod with sum gress pull rod backdown and butten her back up..I would use 220 paper I know this works iv dun it..Artie

 

[HemiEd]

use a long peice of emry paper about two feet wrap it around the crank pulling it back and forth untell clean.take sum carb cleaner spray it clean.put new bearing on rod with sum gress pull rod backdown and butten her back up..I would use 220 paper I know this works iv dun it..Artie

Yeah, this is what I meant by abrasives, done it more than once. I finished it up with 400 wet and dry though. Had them come out pretty nice, but you never know how round they are, no matter how hard you try and do it evenly.

 

[daredevil]

If it spun the bearing i,d be willing to bet it will need more than a polish. Slap it back together with a piece of belt leather against the crank journal.

 

[HemiEd]

If it spun the bearing i,d be willing to bet it will need more than a polish. Slap it back together with a piece of belt leather against the crank journal.

I have heard of that a lot from the real old timers, even using bacon. I wonder how long that lasts.

The other one, was sawdust in the rear end to make it quiet.

 

[cudamark]

Whichever method you use, make sure the crank is clean before you reassemble. If it were me, I'd pull the rest of the bearings (including the mains) and then do the 'regrind". After that, spray all the oil passages in the crank with carb cleaner and blow them out with compressed air.

 

[waggin]

Thats makin sense !!!!!

Whichever method you use, make sure the crank is clean before you reassemble. If it were me, I'd pull the rest of the bearings (including the mains) and then do the 'regrind". After that, spray all the oil passages in the crank with carb cleaner and blow them out with compressed air.