[Farmall] O-12 chronicle, part 3

olmstead at ridgenet.net olmstead at ridgenet.net
Sat Nov 22 18:01:27 PST 2008


I bit the bullet on the leaky radiator.  The new core that I had ordered
from Rice Equipment arrived after I had the radiator partly assembled
using a 'good looking' core from another tractor.  It may have looked
good, but it had one very leaky tube.  So I pulled the radiator back off
the tractor and dismantled it.  Only took one evening to accomplish that;
no rusty bolts to cope with.

I have mixed feelings about the new radiator core.  It came in a box
labeled Detroit Radiator.  Hopefully it was made in USA.  It will probably
cool a lot better than the original IHC radiator; it has three layers of
tubes vs the two layers in the original core.  The top and bottom plates
(what the tubes are soldered to) is heavy brass; considerably thicker than
the original.  One thing I didn't like about it was the square corners.  I
had to grind them off to match the contour of the radiator top and bottom
castings.  And the fins are brass foil, maybe half as thick as the
originals.  I bent some of them just by brushing my shirt against them
while lifting the radiator back onto the tractor.  The core came
unpainted, so I'll probably wind up painting it black later.  And four of
the bolt holes were punched about half a hole off; I had to drill them out
in order to get the radiator tank bolts in.

Got the radiator completed last night and bolted it back on the tractor. 
Today I filled it (first with water), and verified that there were no
leaks by driving around for a while to get the coolant nice and hot.  Then
I let the engine cool and I dumped the water and refilled the cooling
system with 50/50 antifreeze and water.

There's really not much more to do.  The engine was only running on two or
three cylinders this morning, so I cleaned and regapped the sparkplugs. 
The plugs showed a very rich mixture, so I leaned out the carburetor main
jet a bit.  I still need to check valve rocker arm clearances.  The engine
sounds a bit clattery; I don't know yet whether it is valve noise or
piston slap.  Probably slap.  Not a big deal.  I already knew that the
bores were probably a bit loose, and the rings are leaky.  But there's no
noticeable smoke, so they're good enough.

The tractor runs fine.  I was going to drive it to the nearest gas station
(about two miles away), but the idea of spending an hour cooped up in that
tiny cockpit didn't appeal to me.  What are you supposed to do with your
legs and feet?

I have one more modification to make to get the tractor ready for its
movie career.  There's a removable cover plate on the transaxle housing
right above the PTO shaft.  I'm going to take a spare plate and mount a
pintle hook on it.  Most aircraft towbars have a loop intended to be
dropped onto a pintle hook.  I wouldn't recommend this modification to
anyone who intends to pull serious weight behind their tractor; mounting
the hook on that plate puts it up too high, pretty much on the rear axle
centerline.  Drawbars and tow hooks need to be mounted well below the axle
centerline in order to prevent the tractor from doing a 'wheelie' when the
load gets too heavy.

But for the documentary, one night of pulling a relatively light aircraft
on level ground, the high hitch mount is tolerable.  I'll take it off
afterward so that I am not tempted to use it for real work.

I'd like to have a real pintle hitch for an I-12; I've seen a picture but
never touched a real one.

I'll try and get some pictures of this and a couple of other O-12s up on
PhotoBucket before too long so you can see what I've been up to.

-Karl




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