Yes, not really sure how long.  But it WILL LIVE AGAIN IF I HAVE TO WITHDRAW EVERY LAST PENNY FROM MY 401K! (but hopefully not :), although today's spending was a good start on that).

It is a 1952 CA.  Positive.  It has no 3-point hitch, just the normal 1952 pin hitch.  In the picture, the drawbar is installed.  The lift arms are fully down and the drawbar attaches to the lift arms and fits inside the U shaped arms.  I was looking for a ready made 3-point kit for it but didn't find any.  I see a kit that mounts on a drawbar, although not the pin hitch drawbar.  I was thinking I could adapt the pin hitch drawbar to attach via split bearings to the rockshaft and thus my other post asking about the dimensions of the rockshaft.

Older CA, the lift arms run down like that, but you can put a 3ph on one, I have two CA's and I put a 3ph on one to use a finish mower on.

https://www.allischalmers.com/forum/ca-3-point-hitch_topic169749.html" rel="nofollow - https://www.allischalmers.com/forum/ca-3-point-hitch_topic169749.html

That's the snap coupler draw bar.  The pin hitch drawbar attaches to the lift arms, so I either have to first convert to snap coupler or I have to figure out a way to detach the pin hitch drawbar from the lift arms and attach to the rockshaft via split bearings or other custom mount.

I searched Steiner and several other places and they all said there was nothing specific to the CA (and probably more so the pre 1954 CA).  If you know otherwise, I'd like to know where to get it or what mods are needed.  I think I have a suitable mod in mind, if there is enough clearance behind the rockshaft.

yes

https://www.allischalmers.com/forum/2point-to-3point-hitch-ca-conversion-question_topic51797.html" rel="nofollow - https://www.allischalmers.com/forum/2point-to-3point-hitch-ca-conversion-question_topic51797.html

Borescope pics, some ok, some not so ok.  Not the best image resolution.

Engine is locked.  Brother has not decided yet.  He was the last one to put new sleeves in it, so he's familiar with its issues.  He's researching and thinking it over.  He originally thought he would soak it for awhile, may still do that.

Yes, but the 1952 did not come with a snap coupler.  After 1954 it was available as an add-on.  Since we have no snap coupler implements, only those that came with the original pin hitch and lift mechanism, I wasn't planning on converting to snap coupler at this time.  I was wanting to make do with the original drawbar, but because the cross member goes all the way across between the lift arms, the 3 point lift arms would probably hit it on the lower end unless I mount the front pivot up quite high (to get the 3 point down to the recommended 7-8 inches from the ground).

Sorry, I've looked at that one many times but missed the tiny inset image showing a second version with the snap coupler loop having a tiny pin receiver welded on top.  The images on the OKT site are mostly too small for me to read without a magnifying glass.  But I also may have not looked too hard because it says "light duty" and does not look to me to be well designed/made.  "light duty" would mean category 0 to me.  It's hard for me to tell without dimensions, but it appears to have very narrow spacing of the cat 0 version.  It does say cat 1 on the OKT site.  Another thing is the arms appear to be fixed width.  They're supposed to swing a little (maybe one swings and one doesnt).  I'm no expert in 3 point design, but at this point, I'm not liking that one.  Maybe I could be talked into it.  

the second design is one that you bolt a cross bar to your  drawbar, under the axle.. then mount the two lower 3 point arms to it.... There are other ways to do a 3 point, but the only AFTERMARKET are one of these two designs... You can do it different, but it will be "home made".

Well, darn, this is the only Cross I've seen that has a CA non-snap-coupler option:   https://oktractor.com/zen/index.php?main_page=product_info&cPath=1_13_195&products_id=204&zenid=r6hptdv2h5ihrrccehhp5nluv3" rel="nofollow - https://oktractor.com/zen/index.php?main_page=product_info&cPath=1_13_195&products_id=204&zenid=r6hptdv2h5ihrrccehhp5nluv3

I went to the Cross website itself and found no hitches at all.

OK Tractor has this one with an option premade for non-snap-coupler (that I missed before).  Like I said, didn't like the design of it, but when time comes I might choose the easy out.

I'll add that OK Tractor seems to have this one for about half the price of Steiner...

One of dislikes about the design is that I would prefer that both arms pivot separately.  In the snap coupler design, pivot of the fixed arm is relative to the moveable snap coupler tongue.  In the non-snap coupler design, it has a pipe welded across the tongue.  Unless there is a lot of slop in the size of the hole, there would not be proper pivoting of the "fixed" arm.  And I don't think you want a lot of slop in the hole for the pin hitch.

Yes, but this would be the non-snap coupler version with a weld on mod which would prevent left to right swing as well as rotational swing.

I'm up against my spending limit for this year, but when I do this, provided I can devise a suitable drawbar mount modification (keeping the existing 1952 drawbar as is if possible), I'm leaning towards a drawbar mount version for the WD45, perhaps without the sway block (my drawbar mod might suffice for sway block).  I tried sourcing the individual parts (arms, drawbar mount), but that cost was way higher than getting the equivalent kit and throwing away unneeded parts :(

possible hitch design for snap coupler loop.

Yes.  A slightly better design might be an add-on bracket that sandwiches the snap coupler tongue (top bracket and bottom bracket, with perhaps loose fitting bolts, one right in the inside circular bend of the tongue, one at the rear.  Then the pin sleeve would be welded onto either bracket.  That would preserve the integrity of the tongue as well.  Being loose fitting, it could give you enough range of motion at least side to side.

De-brushed...baby steps.  Several days soaking in atf, still locked tite.

make sure when in Neutral that the tire will move.. That tells you the transmission is not locked up also..

Some selected progress pics.  New front and rear tires.  New 12 inch rims on back with 13.6 Titans.  New tires on front.  Rims and front pedestal were sand blasted as was rear hubs and final drive near the wheels.  One front rim was welded by dad in the mid 1960s.  It's amazing that there's been almost no major deterioration since then.  Only a few tiny pin holes near the original welds.  The rear hubs and locks cleaned up very nicely.  Only one of the lock bearing surfaces was slightly pock marked.  All were very usable.  All reassembled with anti-seize lube.  The locks locked up tight.  I was amazed how smoothly they operated.  I stumbled upon the lock/lug wrench in the garage, and also the associated 5/8 inch lever bar.  I painted them orange so I can remember them :)  Everything was sand blasted primed and painted.  Some key areas like inside the front rims have approximately 10 coats rust reformer and of paint in total.  The inside of the front rims were a bit flakey (rust) but with angle grinder, wire brush, and sand blaster, they came out decent and smooth.  Tire guy had no qualms with them.  I may eventually replace the front rims, or maybe just the welded one which doesn't look as nice.  The tractor has been moved to a garage for engine assessment.  It will get rebuilt regardless, but there may need to be a section of the block re-welded.  Dad welded it in the early 70's (or thereabouts) but did not have the right welding equipment on-site at the time so it continued to have a slow coolant leak.  Believe the weld is intact though.

The starter motor was removed for unknown reason, but I tested it and it is fine with not a single issue with the gear teeth or throwout.  Was inside the garage for 40 years.   The original generator is another story.  Was in pieces with coils toasted and loose.  Believe I can get it rewound locally.  I inspected part of the flywheel which seems fine where I could view.  I think the transmission is ok but could only get it into reverse for the trailer ride.  One brake seems functional, sort of, the other seems to be rubbing full time but not forcefully and the pedal won't depress beyond an inch or so.  I can see a broken spring which may be wedged in the way.  Steering play seems no worse than I remember it.  I remember that the front rim welds were heavy enough to cause a little wobble at full speed.  I found the ammeter and control panel.  The control panel  cleaned up nicely, but all switches and ammeter were toast so I'll be rebuilding that, cleaning up the starter (maybe more if needed), and the generator if I can.  I'll probably use stainless fasteners in key exposed places.  Nearly all electrical wiring seems haphazard.  It seems to have had a regulator installed at some point, but no reference in my service manual so I'll have to research that further.

It was not uncommon to remove the light switch and put a 6 volt regulator near the generator and let it do the job.... If the battery was changed to 12v, then yes, you need a regulator to handle the job.

I found front and rear cultivators, disc, plow, and planter.  The cultivators are in the worst shape probably.  Lots of trees growing through it.  One of the sweeps is exactly in the middle of a 1.5 foot diameter scotch pine tree at ground level.  It seems to be sideways.  Couldnt see enough to see if its twisted or just on its side.  It didn't quite logically compute.

It's 6 volt.  Plan to keep it that way.  The regulator was mounted just behind the starter motor.  I don't remember it at all, so maybe my uncle added it in the 70s.

if you need a new wiring system for that project, visit our website. We do everything electrical and touch on each area of the Tractor. I do Carb, Generator, Alternator, 3 position switch and Starter rebuilding. Be happy to help you out with anything....

Steve@B&B

bb-customcircuits.com

Already bought one of your rebuilt switches.  Generator was toast, being completely rebuilt and converted to regulator style operation.  Starter was in very good condition, but I opted to have him recondition it as well.  Fort Worth Starter and Generator.  I'll be doing the new wiring harness myself.  Already have it.

While engine block was out to the machine shop, I prepared the front half.  Sheet metal was taken to a body shop for some rip and dent repairs.  Installed a new throwout bearing although the old one wasnt really very bad.  Clutch plate was relatively new.  Also ran a new wiring harness.

Crankshaft had some minor pitting but overall wasnt that bad.  Machined everywhere needed.  Had too much end play when we got it back so we sent it back out for more work.  Originally, the machine shop documented the wrong specs on the work tag so we ordered the wrong bearings and had to do that over as well.  Those issues were the source of most of the delay in getting the engine going.  I had high hopes, but it didn't happen.  Work is ongoing as time permits.  No the M doesn't run either :(

After I got most of the front half ready for the engine install (minus sheet metal), I replaced the brake pads.  This is the "good" one.   The left one was rusted in two at the hinge.  Kind of a chore to get all the rat and mud dauber nests out through those cubby holes.  Must have pulled 2 gallons of junk out of there.  The drums should probably be worked on but I think they'll be fine besides wearing the pads out a little faster.  There was plenty of metal left.  Probably because it hasn't had properly adjusted brakes since the 60s (i.e. little contact).

I was able to get the plow up out of the dirt and on some temporary blocks (I ran out of time and just used whatever I could find).  The frame looks like it will clean up ok.  The plowshare/moldboards are broken.  The pieces seem to be lying around in the garage, could probably be welded up (or replaced).

Here's the cultivator previously mentioned as having a tree growing around it.  That will be fun to remove.

And the disk.  Didn't get a picture of the planter (forgot when I decided to de-tree the bulldozer).

3 coats of primer and 3 coats of orange.  4 and more coats of primer or orange in strategic areas.

Offsetting was sometimes used in small engines when no valve rotation device was present to achieve rotation.  Offsetting is not supposed to be needed with a valve rotation device.  It certainly should not be so far off that it's barely contacting the valve stem and leaving giant divots because of force being limited to a tiny contact area.

I just came in from my morning fall ride on mine. Took the dog for a walk, so figured I'd give Allis a run too.

I just posted updates a few days ago.  It's not back together yet but mostly finished the engine rebuild internals.  I'm working on some hydraulic system mods at the moment.  I'm creating a pedestal out of a trailer pintle hitch and a hitch extension to get me the required height above the tires.  I've got the base complete except for painting.  I'll start on the platform for mounting the spools tomorrow when a connector arrives and i can determine the width of the side by side spool sets/valves.  I don't expect any significant progress before the spring.  I hate working in the cold :(

Awesome! I'll be watching for your future updates. You might teach me a few tricks to do to my CA.

Progress 10/30/2023:  Designing a removable hydraulic console intended to bolt to the left side fender.  The console consists of a pintle hitch, and a hitch extender mounted vertically with a custom tray resting on top of the extension which is removable.  Two single acting valves mount to the side, a 4 spool valve set on the top.  It sticks out over the tractor tire for space reasons.  It may or may not fit exactly where I designed it to sit (may be too close to the seat), but I can move it forward or backward if needed.  The tray itself is designed to slide left or right.  I still have some plumbing work to go for the return.  Perhaps a little goofy, but fun anyway (I'm retired, I got time) :)  It weighs a ton...

The back view showing the mechanism for sliding the tray left or right.

It includes optional hose supports that can be added or removed when the dual acting spool valves on top are used.  

Closeup of a hose support.  Since the dual acting valve hoses will come off straight up, this supports them at about 16 inches (can be lowered) to prevent sharp bends.

The bottom (pintle mount) section will be bolted to the fender wall.  I haven't drilled those holes (in the pintle bracket) yet so I can determine the best position.  I measured it and know very close where the holes will go but I made the bracket a little longer in case I need to adjust it right or left.  The top section is the removable part via the hitch pin.  I'm trying not to physically modify the tractor, just using existing bolt patterns as much as possible.  The threaded rod is designed to allow the tray to slide left or right (it is then tightened in that left or right position).  I was thinking ahead to deconflict it with my idea for a roll bar/canopy mount that mounts to the axle but will rise just outside the fender wall (so the wheels will have to be slightly spun out).  When that roll bar/canopy is installed, the tray will have to be slid right/forward to deconflict (since it sticks out over the tire).  The pintle hitch is mounted to a piece of 4 inch x 4 inch angle iron that I cut out the left and right floor sections.  The right section had to be cut to deconflict with the brake lever.  The left side was only cut for symmetry.  The forward fender bolt is around 4 inches from hole to back of brake lever.  The other fender bolt is 11 inches behind the forward fender bolt.  I have about an inch of play to adjust the position to deconflict with the brake lever and the seat.  

The console is fairly well balanced.  There is little stress on the mount when you operate the spool levers which have quite strong springs.  That was one worry with only having two mounting bolts.  I can add a horizontal support later if needed.

Quite a bit of trouble getting the severely dented gas tank fixed (someone felled a tree on it).  First took it to a large body shop.  They had it for a few weeks and decided they couldn't fix it (welded pins method).  The metal was too thick and the pins detached.  Then took it to a tractor renovation place and left it for 8 months (apparently out in the weather, I had to repeat the derust process).  They assured me repeatedly they'd have it ready but when I finally arrived they had not been able to find anyone to work it.  So I started driving from shop to shop and finally found a semi-retired guy to fix it (for a very reasonable price).  He did a pretty good job given the condition (yes I could have replaced it).  Needless to say, this caused quite a bit of delay/progress hindrance.  It came out looking pretty good.  The paint doesn't look quite as good as I'd like.  Really bad conditions:  1) Indiana is pretty darn wet and humid in May and I just could not get the water down in the line.  2) Bugs galore.  Wet paint seems like a bug magnet.  3) Sandable primer (600 grit) just never got smooth enough.  4) Oil based enamel paint takes weeks to dry and gets lots of dings if you're in a hurry.  Doing it over I'd use a faster drying paint.  The primer I used dries in minutes and is hard as a rock.

There were a few leaks in the top left over from the welded pins which I had to weld up.  Then I used epoxy as the major filler and finished with a skim coat of bondo (no picture, I kept forgetting to take pictures).

Fit check.  I should not have put the strap on yet.  The paint was still too wet although dry to the touch.  The strap goes on over the tin not the tank.  Had to make a small paint repair to the tank but it will be hidden under the tin.  I had used a rubber strip on the strap rather than a nylon strap material (fixed later).  The rubber was really sticky and welded itself to the paint :(  The tank was also internally derusted (6 or 7 times) and POR 15 gas tank sealer applied.  That stuff seems pretty good.  Hard as a rock, coated very well.

I worked on the steering wheel off and on between paint coats and maximized multitasking as much as possible.  The original was in really bad shape with most of the bakelight near each spoke all or nearly all missing.  That was a lot of small batch mixing.  Yes I could have bought 2 of them for the price of the epoxy (not to mention my time).  I could have spent a bit more time glazing.  Epoxy isn't very well suited to that.

Sand blasted and made some minor repairs to the original shutters.  They were in really good shape except for one torn hinge.

Installed.  This pic also shows the aftermarket radiator overflow tube.  The nipple sticks out way too far and the hose gets crushed by the cowling.  I shortened it and routed a smaller diameter tube differently.  I'm not quite happy with it and will probably improve it later.  The original radiator has a deep recess in the top for the tubing.  Again the aftermarket radiator shutter mounting holes didn't line up but was a simple hole size increase to fix adequately.

2000f paint on the new manifold.

Manifold and muffler installed:

Rebuilt original generator with regulator and rebuilt carb installed:

The mounting holes in the aftermarket radiator (made in Turkey) for the cowling didn't match up.  I had to increase the hole sizes for the bottom 2 holes (were 1/4 inch holes) to 3/8 inches and then had to slot the bottom holes because they still would not line up by 3/8 or so.

After reversing the radiator mounting plate to position the "hole reinforcement" towards the engine, the radiator fit properly.  This is after I rewired and installed the lights and battery.  I also had to clean up the threads on the large steering linkage on the lefthand side of the tractor.  I then installed two new castle nuts.

Likewise, the hood was pretty beat up.  I worked for hours trying to get it straight enough to avoid bondo, but failed.  I don't have the nice body metal working tools there that I have at home.  But I was running out of time so I'll consider further improvements in the future.  The hood and radiator cowling were also welded up by a body shop due to various rips and tears around the mounting holes and the oil filler hole.  The headlights were basically decapitated at some point.  One could have been easily renovated but the second one would have taken quite a bit of effort (still doable), but I elected to get new ones.

I was running out of time so I elected to do a good enough for now effort on the tin.  I can easily address that later.  There is more functional work to be done first.

We were able to get the engine to fire and briefly run.  It sounded really good, all 4 cylinders fired.  However, there seems to be a fuel problem.  I suspect my carb rebuild went astray somewhere.  There was one jet I was unable to remove and replace, but it was nice and clean.  Also, the new battery I installed was discharged when I bought it and self discharged overnight (I checked for leakage and didn't measure any).  The behavior is kind of strange with the charger, but it is one of those "automatic" chargers.  I just want a switch to select 6V and an ammeter to tell whether it's sending current in.  Basically, at 100% charge it turns the engine over really well...for 2 revolutions then it can barely turn it to the next compression stroke.  Charge it back up, you get 2 good revolutions then the same behavior.  Put it on a load tester, shows good though.  I don't trust the load tester.  The guy at OReilly told me he's never sold a 6V battery before.  I suspect it was in the back uncharged for years.  After a full charge (100%), if I disconnect the charger, wait 30 seconds and restart the charging, it behaves as if self discharged.  One time the charge indicated it started over at 13%, the next time at 70%.  I don't trust the battery or the charger :(  

I also had an issue with an aftermarket fuel bowl.  It absolutely would not screw into the gas tank.  Any of several 3/8 pipe fittings I had laying around worked fine and easily screwed in.  I ended up having to buy a die and "fix" the threads.  Even then, it wasn't really happy screwing in straight.  But I finally got it to go in properly.  I fear though next time I remove it to clean/replace the screen, I may not be able to get it back in straight.

So, in working on the timing, we found the FIRE mark on the flywheel.  Then we found a CENter mark just after the fire mark...then we found a second CENter mark.  Are there two center marks??

The throw-out hub and bearing were both completely locked up, but they cleaned up nicely.  The bearing was in excellent shape (given that it was probably not in contact with the clutch housing for 40 years).  The adjusting hub/housing looked near new after I cleaned it up.  I did need to clean up the threads to stop some binding, but nothing major.  I think that the last time the clutch was worked on they just bolted the clutch plates together, but not verified...it may just be rusted fast.

I did get the engine running fairly well.  The main issue initially was the throttle control wasn't applying enough force against the wrong carb throttle linkage spring (new one hadn't arrived yet) and it was just idling too slow to continue running.  I also had to fix a weeping leak in the carb float bowl.  The only remaining leak appears to be the oil drain plug.

Also, initially there was no oil pressure.  This caused fear and dread :(, but I was able to prime the pump and got "good" pressure of 10psi at idle and up to 12psi at a slight rev.

I improved the battery cable ground connection.  It appears I only THOUGHT about cleaning the paint off the connection (grounding was through the bolt head, but may as well get full surface contact).  There's not much evidence that this improved the battery performance, but I think after the engine loosens up and I get it timed properly it will be fine.  

I also verified that the new regulator was properly polarized and at the correct voltage before connecting.

Not wanting to fire up the compressor, I elected to use the drudgery method of wire brush and Dremel to clean up the seat spring and shock absorber.  They cleaned up well and I got them primed but not painted.  The shock absorber was still working reasonably well (pretty sure it's the original).  I also removed and cleaned up the small, curved bracket on the seat mount arm.  

I prepared the rockshaft and several other linkage parts and the tractor rear end housings for sand blasting.  It appears that the poor tractor had been buried in mud up to the seat spring at some point.  Caked on thick.  Some of it didn't want to succumb to a chisel.

I welded up the right rear final drive oil pan and sealed it with epoxy and POR15 gas tank sealer.  Primed and painted, ready to install.  I then cleaned up the new rim and tire of all the leaked oil and sand blasting grime that got stuck in the oil.

I welded up the seat.  This was a bit difficult because the metal was so thin.  Kept burning new holes but I did get all of the cracked areas attached back together and then smoothed by grinding and epoxy.  I had to grind off all around the edge.  It was jagged and sharp.  It's now less jagged and less sharp (but substantially all there).

I applied the bed liner material to the steering wheel.  I didn't think the prior new paint finish would hold up very well.  It turned out awesome.  It looks great, nearly as good as a new one.  I forgot to take pics this time, too busy trying to cram as much as possible into a week.

I installed a new 4 stage compressor air dryer on the wall and got it ready for use next trip.  This makes 5 stages given the one just after the compressor.  If it's still spitting a stream of water out after this, I'm gonna be upset :(

I was able to return the power director hitch-to-hydraulic pump control rod to its plunger hole.  Hard to imagine how it got knocked out without doing any damage at all.

I installed a solar trickle charger to the front of the barn and soldered an extension cable to the too short solar panel cable and ran it across the rafters to drop down at the tractor.  I bought another one for the garage for dad's 57 Thunderbird, but didn't get it installed yet.

I picked up my new suitcase weights from Fastenal.  Four 70 lb weights.  I think that will suffice for nearly anything I might want to do.  I also got 2 front wheel weights.

Helped my brother unload the new 6-foot finish mower and tarped it.

Took measurements for my new tach sensor design.  I'm thinking it will install at the bottom bell housing inspection hole and mount to that drop down loop just in front of it.  Since that's probably intended as a "weep" hole, I'll need to consider that.

Didn't get pics this week.  It was mostly me getting filthy removing rust and grease and mud from various parts in prep for sand blasting.  Saves a huge amount of blasting media if you get the 1/2" thick encrusted sections knocked off first.  I got a brief first start and run clip I may put up, but even it is only about 1 second long.

https://www.youtube.com/shorts/-eZ2IIsBJSQ" rel="nofollow - https://www.youtube.com/shorts/-eZ2IIsBJSQ

Your doing a awesome job. Maybe I will get some inspiration to work on our CA too.

Thanks :) It's a bit challenging for me.  I'm doing it by traveling a week here and a week there and cramming as much as I can fit in while I'm there.  If AGCO gets the clutch rebuilt within a month or so, it looks good for having it working by the end of the year.  I expect hydraulic pump issues, but not going to try it until I can get all the fluid changed out (already largely drained with some water present).

Code appears to be working.  Took roughly a day.  Most of the trouble was getting the Nano ESP32 pin references right.  With the original nano, referencing the pin number directly worked fine.  With the new ESP32, it seems to reference GPIO (internal processor) signals (sometimes).  Resorting to using the pin variable names (e.g. D13 for pin 13) seemed to work in all cases.  There is a setting in the IDE to change the pin reference to GPIO or PCB but I think there may be a bug somewhere for the Nano ESP32.  

It doesn't really amount to much, just counts IR sensor pulses in a given time span and displays the results.  All of the conversion factors are based on tractordata.com data so may or may not be accurate in every case.

As designed, it contains code for B, C, CA, WC, WD, WD45, WF, UC.  The default is CA if none of the open/ground pins are grounded (4 pins to represent 4 bits so there is a little room for growth).  I may or may not include a DIP switch to change the setting in the first one.  Verified that it works ok on 6V and per the chip spec, down to 5.5V (of course all the logic is 3.3V).

I need to research whether I can control the TFT brightness.  I think it's not controllable on this particular display (off or full brightness).  I may program it to go to sleep after 10 seconds or so and wake up if the RPM value changes by some tolerance.  I'd kind of like to avoid connecting the touch screen, but it may be necessary as an alternate "wake-up" signal.  The ribbon cable for the TFT is on order. 

I mostly completed the IR sensor to bell housing mount.  I need to adjust the IR sensor sensitivity.  New ones seem to be set to minimum which is about an inch from the sensor.  That may be just a hair too short for the mounting position.

Of course, I still need to test the pulse count accuracy. It seems like the detection is very fast 

I could also add a battery voltage sensor (have one already but it's 5V instead of 3.3V so I'd have to level shift and scale it).  That might be handy.  Edit:  It's a simple voltage divider so I just limit the max input voltage (sense no more than 16.5V) and add a zener to clamp the output at 3.3V so as to try to not damage the Nano input if it exceeds the max sense for some reason.

After all that, then decide on (weatherproof) enclosure and faceplate.  It will have an on/off switch as well.  The cable will include a weatherproof disconnect at the sensor and at the CPU enclosure so they can be worked on independently.  I'm thinking it will mount on the steering column but haven't decided.

The RPM below is how fast I waved a white ink pin in front of the sensor.  I verified that a black ink pin doesn't cause a signal.  I need to multiply it by 60 in this case (code fixed).  I haven't decided on the best sampling method/time span, but I think a 1 second update rate will be ok.

Didn't like the design of any I could find.  Making my own out of a WD45 one.

I modified the pulse measurement approach slightly.  Instead of counting pulses, I decided to just measure the time from leading edge to leading edge.  I then sample 5 sets in a row and average those to reduce noise.  This has the added benefit of being able to handle much higher pulse rates since it drops out of the loop as soon as a pulse transition occurs, ready for the next test.  I tested with a 4800 rpm 1.5VDC motor and it appeared fairly accurate (as well as reading a 3x value when it detected each of the 3 fan blades...was surprised it was that fast).  I may need to set up a more realistic test though to determine if 5 readings is enough to keep the noise down.  

I also added the code for the battery voltage sensor, but I'm unable to find the one I thought I had so a new one is on order for tomorrow (another $5 down the drain).  So I may have to tweak the resolution multiplier (changes one number) once I get the details/test of the one I ordered.  Next task is to decide if I can dim or blank the display after a period of steady state operation and how/when to "wake up".  That's the last software task that I plan, I think.

Edit:  Researching the TFT display, it appears that the brightness can be controlled via an analog signal.  Others require a PWM signal, some are not controllable.  This doesn't necessarily change my approach, but I COULD fairly easily add a brightness control interface rather than just on/off.

Edit:  Added benefit to making my own is that I can make it waterproof.  I now have the enclosure, aluminum, and acrylic sheets for the faceplate...my goal for 7/17.  I also decided to order a different PCB project board that fits the enclosure a little better than the one I have.

Edit:  I decided that the plastic enclosure was not going to be adequately sturdy.  Waiting on a metal enclosure.  Additionally, the plastic enclosure was a bit bigger than desired.  Plastic size choices are limited, but the metal one is much closer to the desired size.  Should arrive by 7/24.  I can reuse the faceplate as-is with the new enclosure.

Not a huge amount of (mechanical) progress but I have the TFT mounted in the enclosure faceplate.  I either need to cut a gasket for underneath the acrylic window or I need to seal it around the edge.  Because the faceplate is too flexible, it probably won't seal in the middle with a gasket, so I'm leaning towards black silicon seal around the edge.  I guess I could add two more mounting screws in the center.

Mostly waiting on electrical parts which should arrive today and tomorrow.  I need the PCB arrangement decided before I drill holes for switch, cables, and mount.  The enclosure is an odd size.  I didn't find any PCBs off the shelf designed to fit the mounting slides, but I found one that should be very close.  I can always make a mounting tray though, no big deal if they don't fit quite right.

I did change the software display brightness dimmer timer to 20 seconds from 10 seconds.  Ten seconds was a bit too annoying.

I also researched adding a hydraulic pressure sensor, but the sensor cost more than the entire project so far.  Besides I already have a mechanical gauge. 

My next trip is set for mid August.  I enquired the (ex) AGCO dealer progress on my hand clutch rebuild.  There was zero progress, hadn't even looked at it after 3 weeks (told me he'd look at it the following week after I left it).  I'm getting the impression there's a lack of interest although he seemed fine and interested when I left it.

The black tape is a kludge to prevent the (metal) TFT sides from contacting the metal enclosure.  I also applied some insulating glue.  With a positive ground system and a negative ground TFT, who knows what might happen, maybe WWIII :(

Edit:  just received the PCB and they fit perfectly so tomorrow I can decide on the internal arrangement and start wiring.

I've completed the enclosure parts arrangement design and drilled mounting, cabling, and switch holes.  I believe I can get by with a single PCB by dispensing with the dedicated screw terminals for power and RPM sensor (they'll go to a screw terminal anyway on the Arduino breakout PCB).  

The clamp should nicely fit the steering column (I have different rubber insert sizes to try but I believe this is the correct one).  Since the steering column is at an angle, the mount can be locked at any angle as well, but the detents are at 90 and 45 degrees.  There will be a push button on/off switch (with blue illuminating ring), and there are two waterproof cable clamps.  The large fender washers are to distribute the strain to a wider area.  I was afraid the ABS enclosure wouldn't stand up to this mounting arrangement, so opted for a metal enclosure instead.  It should meet IP6x weatherproofing requirements (resistant but not submersible).  I'll probably need to seal the switch better, it seems substandard as-is, although claims IP6 rating.  I'll probably include a silica packet inside as well.

PCB wiring is complete barring test issues.  Took quite a while to get all the parts.  I made a last minute change to add an inline fuse.  Not quite happy with the cable mess that resulted.  I may improve that tomorrow.  It was necessary for me to buy a heavy duty magnifying headset to finish the PCB.  I just can't see anymore.  Works really well, but the lenses are acrylic.  Better not splash any parts cleaner fluids :(  Only thing left before I ship it to dad's is to make the header connectors for the sensor itself.  I'll make one end of the external cables (plug/sockets)  but the other ends will depend on the routing (length) I decide when I install it, so I'll make those ends there.

Two header connectors on the PCB are for the TFT and the on/off switch.  The external inputs (power and sensor) attach via the screw terminals on the bottom.  This may not be the best mechanical approach, but I was trying to use on-hand parts as much as possible.  I may make additional labeling improvements.

First power-up of the PCB was successful (nothing blew up).  I do have a few issues to address.  1) The bezel is covering part of the display (thought I was careful, but apparently not careful enough).  2) The scaling for the battery voltage sensor is off.  I had set it for a particular prototype resistor value and that resistor disappeared into a black hole.  New resistor is a slightly different value (they have a fairly wide tolerance) plus I added a new zener clamp circuit to prevent the input from going over 3.3V (which should give a measurement range up to 16.5V power input)...slow progress in between yard work, pool work, etc.

This is the "final" tach version (depending on how well it works installed).  I still need to make the "power" harness (both harnesses will be cut to length on site).  For this to work properly, the flywheel outer edge must be coated flat black and a single IR reflective strip will be applied.  The reflective surface must be completely smooth to prevent spurious impulses.  Depending on whether I can mount it close enough (< 2 inches) a plain white strip of tape or mylar will work.  In testing, silver mylar worked slightly better, giving increased range and a stronger more consistent return.  The width of the marker is to be determined.  I'll start with 1 inch to provide a reasonable duration and reduce likelihood of missed pulses.  

I also added a nice foam rubber gasket to the faceplate bezel and cleaned up the surround that was blocking some of the display pixels.

A view inside:
 

Here is a full view.  This coating is much tougher than the paint.  I had used a very tough/hard paint, but I was worried it wouldn't hold up well.  I think this will hold very well and has a good feel to it.

I was running out of time last trip so I decided to take the axle to the local (former) AGCO dealer for hand clutch repair.  I was a little concerned because he did the repair (including religning and new springs/ball bearings) without removing the brake drum section from the axle.  I bet that was difficult.  In any case, there was little chance of actually testing/gauging the correct tolerances that way.  After I got it back, I wanted to test it before I put everything back together.  I had to put just enough structure together to operate the tractor (i.e. rails, brakes, seat).  Initially it did not seem to be releasing.  One thing that was concerning is that on at least 2 occasions, in attempting to release the clutch, a large cracking noise was heard, like a spring/ball seat popping into (or out of) place.  This happened two times.  After a final clearance adjustment, then the clutch started operating "correctly".  It still has a slightly "off" feel to it, but my memories of using it are 50 years old.  It does seem to be working correctly though as far as I can tell.

Installed the welded and POR15 sealed final drive oil pan.  Added .75qt 80W90 gear oil...no leaks (yay).  I will give the other (left side) one the same treatment later (not leaking but I bet it has some water in it like this one did).  The rust pattern was weird...just needle sized pin holes with no rust surrounding the pin holes.  How is that possible??

I spent days reworking the hood.  It was severely damaged in a logging accident plus several hail events.  I spent quite a lot of effort my prior trip but just wasn't getting the results I wanted, especially on the sides where the decals go.  That was going to look awful.  So I bought some body work tools and began pounding the heck out of it.  Then I started bondo-ing the worst areas.  I would have had to skim the entire surface to get it right.  What a mess (not to mention the numerous rips and tears I welded).  A sane person would have probably got new tin.

More bondo.  Not clearly visible are the severe rust pits all over.  Like the seat, some of the rust pits LOOK like they're deeper than the metal is thick :(

After 5000 coats of primer and days of sanding, I'd had enough (red deep fill primer).  Good as it's gonna get.

Not really clear but the paint looks MUCH better this time.  I had several issues previously:

1) Compressor was spitting out huge amount of water.  To resolve, I purchased a 4 stage air dryer (which makes 5 stages given the one at the compressor).  This made a massive difference for both painting and sand blasting.  After i got the sand blaster cleaned out of all the hard chunks/flakes of sand, it was greatly improved in performance.

2) Massive bugs and tree residue (in May), plus a lot of rain adding to the compressor moisture issues.

3) I was following the directions on the Tallman's paint can previously.  This time, I used the advice of "random internet guy" and mixed hardener and naphtha thinner in a 4-1-1 ratio.  This massively improved the paint drying time, hardness, and gloss.

A view of the rear end sand blasted and painted.  It has 3 coats of primer and 3 coats of color.   I bought a nice black seat cushion to cover up the crusty seat :)  If I had had another few hours this trip I might have installed the rest, but paint recommends waiting 7-10 days to let the paint cure.  Here I just installed what was necessary to test the hand clutch.  I also drained and put new gear oil in the tranny.  Overall, given that the hand clutch SEEMs to be working, I'm happy with my progress this trip.  A lot of progress in 6 days.  Even spent some time with my brother trying to get the M running :)

One problem I still have is that the governor seems to only bring the speed up to 1/4 throttle.  The throttle rod was "straightened" to just one bend just behind the starter and now gets me full range of the control mechanism minus 1 notch (was 4 notches short before...it starts bending the rod at the last notch now).  I can probably work the bending of the rod a little more and get the full range of the control correct.

I'm guessing that the governor spring is weak, but it doesn't look to be stretched.

The hydraulic hoses are split and frayed, I guess I'll try to replace those (hopefully I can find some swivel fittings that don't leak, I don't like the way they have to be twisted as-is).

I also cleaned up and removed some large dents in the belt pulley last fall and just installed it.

As expected, I need to make two tiny mods.  

1) The sensor housing itself (plumbing T) was cut to the correct dimensions.  But this will require me to mount the sensor on the opposite (rear) side and change the entry point of the cable (no big deal).

2) The display housing needs about 1 inch more clearance to deconflict with the throttle and starter control rods (expected).  (also need thinner rubber clamp mounts since the steering column diameter is larger than I remembered).

Showing where the seat was rusted through and welded and epoxy skim coated.  I originally didn't plan on fixing the hole, but decided to go ahead.  It came out nice and round-ish.  It was sand blasted further before painting but I didn't get a good post paint pic (but you can probably imagine painted rust pits well enough).

Those are some DEEP rust pits.

Installation clearance modifications: 

The tube clamp actually came with a slightly longer extension that I didn't remember.  If that one isn't long enough, I've made one that gives me much more flexibility.  I added a continuous groove for the pointed set screws to sit in to reduce the chance of accidentally pulling out.  There will be lock washers in addition to the jam nuts.  

The original clamp extensions only came with fixed set-screw positions.  If needed, I can similarly groove it given that it's unlikely that the fixed positions will give the correct angle for the display.

The sensor itself had to be cut to fit the opening at the bottom of the bell housing and the mounting ring just in front.  This required me to add an extension on the back side in order to provide enough clearance for the wiring harness.  The pipe nipple was grooved on the end to allow the PCB screw to mount correctly.  The nipple also decreased the clearance between the through bolt and the PCB so I ground a clearance in the middle of the through-bolt and covered it in shrink wrap tubing.  There should be enough clearance, this was just a precaution.

There will be a shortened nipple protruding upward into the bell housing hole to prevent rotation.  The exact rubber sealing arrangement is tbd.  I intended to use gloss paint, but my last can of gloss black stopped spraying properly before it ran out of paint (broken button receptacle in the can)...:(