Clutch Carnage

Self inflicted, of course

I just hate when I do dumb things

We recently got the derelict Model C assembled enough to try to see if it would make some noise. The B-125 combine engine was stuck so we pulled the head and pan, got it freed up and did a basic valve job, we did not pull the pistons nor did we remove any bearing caps.

Hand cranking resulted in no joy, and hand cranking to check compression showed VERY low compression, less than 45 psi on cylinders #1 & #4, less than 10 psi on #2 & #3.

We then connected the derelict Model C to my other Model C via the flat belt pulleys, gave it a whirl and it fired right up!

I immediately shoved the clutch forward to disconnect the tractors, trouble is, there was excessive looseness in the clutch pedal and the pedal slipped right past the physical stop on the torque tube, thus allowing the clutch rod to slam forward into the clutch fingers, instantly breaking them off of the pressure plate.

Besides the obvious looseness in the clutch pedal, which I have since fixed by drilling out the holes and installing an oversize clutch pedal shaft, the clutch operating rod was too long, a previous owner having lengthened it by welding a bolt in it. I had to cut off about 5/8" to get it back to the correct length.

SteveM C/IL wrote: Don't you just love life lessons....

Yup!

I am probably the only person on the planet to have ever put this particular combination of errors together to create this problem in the past 80 years

Grandson and I took another stab at firing up the derelict tractor yesterday. On the first try I forgot to remove the grounding wire I had attached to the magneto but that did allow sufficient cranking to show good oil pressure.

After removing the kill wire we spun it again (using the flat belt pulley connection) and it fired up but wouldn't keep running on its own so we just kept spinning it with the flat belt hoping to develop some compression.

We had filled the radiator with water so no worries about cooling. We let it spin for about ten minutes but it never would keep running without the additional help of the other tractor. The engine did warm up slightly but nowhere near a normal condition.

We then stopped and pulled the spark plugs, all looked good there. Pulling the valve cover revealed good tappet clearance all around.

We then did a compression test while spinning with the flat belt #1-115, #2-80, #3-112, #4-113. Not too bad all things considered, and certainly good enough to keep running even with that weak #2 cylinder. Cranking speed makes a huge difference, I couldn't get over ~45 psi while hand cranking.

The next thing we checked was the spark and timing. The timing was still good, but this Wico magneto, which had been sparking just fine last winter when I installed it, now only showed a feeble spark on #4 and none on the other plugs; it probably just needs the points cleaned again but we swapped in a spare Fairbanks-Morse unit and gave it another whirl.

This time it fired right up and kept right on running all by itself! Lo and behold, these engines do need good ignition Who'da thunk it!

It was getting late and it was time to do chores so we quit for the day; there are still lots of small details to address but we are quite happy with our success thus far.