[Farmall] Another O-12 project, part 2

[John Hall]

I think sooner or later we run into a project we regret following the last 
"mechanic". I got into an Economy Hit and Miss engine once that looked ready 
to run with new paint. It was rebuilt with broken rings, the mag rotor was 
installed backwards, and there was sandblast sand in lots of places it 
shouldn't have been. Oh yeah, it had a 4 inch chrome exhaust pipe that 
stopped at ear level!

John Hall
----- Original Message ----- 
From: "Karl Olmstead" <kolmstead4 at msn.com>
To: "Farmall List" <farmall at lists.antique-tractor.com>
Sent: Sunday, February 15, 2009 10:38 PM
Subject: [Farmall] Another O-12 project, part 2


>
> Warmed up my shop again today and fixed the 'Billized' O-12 crankshaft 
> nose.
>
> Had to remove the front motor mount in order to get access to the 
> crankshaft nose.  I put a floor jack with a 4x4 on top of it under the 
> engine oil pan and jacked it up slightly, then removed the motor mount. 
> Took a few pictures of the mechanical mess that I found.
>
> I measured a couple of good crankshafts in order to determine where I 
> should cut off the welded extension.  The crankshaft originally ended 
> about 0.8" in front of the first thread on the crank.  I marked the welded 
> crankshaft, and cut off the excess with a Sawzall.  I was afraid I'd run 
> into very hard metal, but it was actually quite soft.  I should have cut 
> forward a bit more; maybe as much as an eighth of an inch.  I was hoping 
> to just 'kiss' the original end of the crankshaft, but I actully left 
> about 1/16" of it attached to the stub I cut off.
>
> Used an angle grinder to clean off the excess weld on the crankshaft nose. 
> I could see the setscrew that holds the pin the hand crank engages, and I 
> could see about half of the outline of the pin on each side of the 
> crankshaft.  Ground down a screwdriver until it just fit the setscrew slot 
> and was able to get the screw started.  Lubed it and ran it in and out for 
> a few minutes until it finally came out.  Tried to drive out the pin that 
> the hand crank engages, but it was slightly welded into place.  Wound up 
> drilling it out.  Came out nicely, leaving a clean hole.  Thank goodness 
> Bill hadn't filled up the hole!
>
> Touched up the crankshaft nose with a file and ran a tap through the 5/16" 
> NC setscrew hole.  Cut off a 1.8" piece of 3/8" drill rod and drove it 
> through the hole in the crank nose.  Reinstalled and tightened the 
> setscrew.
>
> It's not pretty, but the nose of the crankshaft is back to stock.  I 
> installed the hand crank assembly temporarily, and it lines up and engages 
> the crankshaft perfectly.
>
> The front motor mount on the -12 series tractors consists of a cast iron 
> basket that surrounds the front crank pulley, and a forged steel piece 
> that reaches the frame rails on each side, into which a sleeve on the cast 
> iron basket slides.  The basket and the forged piece are usually stuck 
> together.  They certainly are on this tractor.  I put the motor mount 
> assembly in my sandblast cabinet and cleaned up the joint between the two 
> parts.  Then I put the assembly on my workbench and soaked the joint with 
> Kroil.  I'll leave it that way at least overnight, hoping that Kroil will 
> work its magic.  As I left the shop tonight, I set the assembly on top of 
> my woodstove, hoping that the residual heat would speed up the Kroil 
> penetration.
>
> If the penetrating oil doesn't do the job, I'll try heating the outer, 
> forged part with the rosebud tip on my torch.  Hopefully it'll expand 
> enough to release the inner, cast basket.  Eventually, if all else fails, 
> I'll cut the forged part off the cast iron part.  I have many of the 
> forged brackets, but no spare castings.  They are broken at least 75% of 
> the time, and I ruined one once trying to pry it out of the forging.
>
> When McCormick-Deering engineers designed the motor mount system, they 
> provided a way for the frame to twist a bit under loads, without 
> distorting the engine casting.  The cast iron sleeve inside the forged 
> steel motor mount bracket seemed like a good idea.  Over time, however, 
> the two parts rust and lock together.  If the frame then twists under 
> load, the cast iron basket breaks.  So I need to free up this connection.
>
> I'm feeling a little better about Bill's O-12 tonight.  I've repaired the 
> worst thing he screwed up.  The rest of the problems are pretty standard 
> F-12 / O-12 fare.  I will need to rebuild a fuel pump and a magneto; I've 
> run through my inventory of rebuilt units.
>
> Before too long, I'll have to move the O-12 outside and direct the spray 
> from my pressure washer into the water jacket opening in the cylinder 
> head.  Now's the ideal time to flush out some of the rust which tends to 
> plug up the cooling system.  I'll check the radiator for leaks and 
> probably dismantle it and reseal it.  The bottom radiator tanks on -12 
> series tractors are almost always packed with rust, and frequently rusted 
> through.  Having rebuilt a radiator a few months back, I know that the 
> work is tedious but not very difficult.
>
> How far am I away from getting this one running?  Two months, I think.  If 
> I were in a big hurry, I could probably  do it in a month, but that would 
> require working in the shop every night after I get home from work. 
> That's tough, because it takes about two hours to warm up the shop using 
> my leaky, smokey wood stove.  Maybe it's time to fire up the propane 
> heater.  If I position it wisely, I can have my workspace warmed up in 
> fifteen minutes or so, while the rest of the shop remains cold.
>
> Might be a while before I report in again, depending on progress.  If 
> anyone would like pictures, please let me know.  My email address is
>
> kolmstead4ATmsn.com, where the AT gets replaced by an '@'.  I can't get to 
> mail sent to my old olmstead at ridgenet.net account.
>
> -karl
> _______________________________________________
> Farmall mailing list
> http://www.antique-tractor.com/mailman/listinfo/farmall