Getting back to MH44 EFI

I got burned out this winter, so no work on it, but getting back to it soon.

Here are my ideas:

I put in a strictly centrifugal advance table, plan to make that a combination of centrifugal and vacuum. I would like to get an advance curve from a high compression 44 or Farmall M, and use that as my high load base, then add a couple of degrees of advance under low load. I also need to check the dwell settings against the desired ones for the coil I installed so that is optimum. If anyone has that curve, I would appreciate you sending it to me.

The computer has a setting for injector delay, I put that in as 1ms. I have been researching this and it should really be between .8 and .9 ms, and found a procedure where I can determine this by changing it and looking at the AFR, so plan to do that. This setting will show up in the linearity of the fuel settings as I go from low to high load. The tractor does not blow smoke, but the inside of the exhaust is sooty, which I think is wrong. I can set the AFR table to match the load curve, then tune to it. I made that table a little rich when setting it up so that I did not burn up any pistons. The table should go from about 14.7 at no load to 12.5 - 13.5 at full load, so will look at that. I have it going to 12.5 pretty quick, would like to move that up to and see how HP varies and exhaust pipe looks. The autotune uses this curve to adjust the fuel settings.

The engine uses a siamese manifold, so the inner cylinders are always going to run richer. I added EGT sensors this winter, so will look at how that is right now, and see if it is worth messing with. I can vary the injector timing, or go to dual injectors if necessary.

Thanks for your interest in this.

Dwell is set to optimize the coli magnetic saturation. As slow as the engine turns (compared to a car) 35 to 40 degrees will work. The coil needs to be "off" at or more than 50% of the time or it will heat. Jim

I'm not familiar with the inside of that engine. Does it have a quench type combustion chamber? If so what is the quench height clearance?
I wonder if at some point (regarding soot, unburned fuel) you'll be bumping up against limitations of the basic chamber design (swirl, turbulence etc). Not to say that MH is worse than anyone else but rather it reflects the knowledge they had at the time.

Forgive me if you covered this in a previous post but what kind of fuel pressure does your system operate at?

When I was a kid our neighbor had a 44 Massey which I thought was "cool". For a while I owned a 44 Special and it was fun to use. It would be fun to have one updated as you're doing, and performing well enough to play with a 3 btm. plow.