MH44 EFI

I got the distributor pickup mounted on the 44 tonight. I changed the system to only use the distributor pickup, but the timing seems to be bouncing a few degrees. I am not sure if I like this erratic timing. I will probably go back to crank sensor for degrees, and add a cam reset pulse in the distributor so I can use port timing. This will allow me to test port timing for now.

David,

There's a lot that you know that I do not. WHat is a cam reset pulse? Forgive my ignorance, but I am intrigued as to your endeavors.

D.

A four cycle engine takes 2 360 degree rotations, or 720 degrees to complete it's cycle. Half of the cylinders fire on the first 360 degrees and the other half on the second 360 degrees. A reset pulse coming from the camshaft will let me know which half it is in. I need to know this to go from a single common fuel injector to port injection.

even tiny bushing wear on the shaft holding the wheel will cause deviation in trigger timing angle. If there is measurable movement with light pressure and a dial indicator, I would replace the bushing, or substitute a precision ball bearing. Jim

The bushings are good, no slop, but I have about .010 of end play right now.

Since it is open to the world, put a single ball bearing ball in the end of a piece of tubing and push in on the end of the center shaft. A right angle drive can make thrust an issue. A cover with a spring loaded ball would keep it under control! Jim

that is a good idea.

Something has me stumped on this, so opening comments.

The distributor rotates CCW, looking down, my calculations had this position as TDC, but I had to rotate shell CW about 30 degrees to get the timing right. The TDC should be either the missing tooth, or one on either side.

What am I missing here?

That is what I do. sometimes they actually work. Jim

Could the prox,or the sensor be to close to the gear or to far away to read it just perfectly?

There is a guy on facebook that's doing something like you show with the distributor, just using it for the impulses for the spark, with 1 coil per 2 cylinders, and has a spark to both cylinders at the same time, so one on the power stroke, one on the exhaust stroke.

Name is Paul Crowe, (920) 810 0946

Seems like he may be able to help you out.

Donovan from Wisconsin

It is reading fine, just the TDC position does not line up with what I expect.

It has been really neat to see this transformation of your tactor. This would be a really great project for someday. What a you using for a controller? How do you figure what injectors to use?

Could the missing tooth could be tripping the proximity sensor near the edge of the sensing pattern instead of directly in front of the sensor? Some proximity sensors have a sensing range and a sensing width twice the diameter of the barrel.

I am using a Microsquirt controller.

I research and calculate initial settings, then adjust for best operations. I am on my third upsize of fuel injectors, trying to meet the maximum fuel demand, but still get a good idle. There are basically two ways to do fuel injection, he first is throttle body, the second is port injection. Throttle body is by far the easiest, as it is really just a more precise carburetor. You still have all the intake runner warming and fuel dropout issues that a carburetor has. The second method is port injection, where the fuel is injected as close as possible to each intake valve. This method removes all the limitations of an intake manifold, so it does allow more precise injection.

I started with throttle body, it really works very well, but I am taking the challenge of moving to port injection, really just for the challenge.

Now for some talk on port injection. The best operation has all the fuel delivered at the intake valve right before it starts to open, so it can warm. You will notice that all newer inline engines have the intake manifold on one side and the exhaust on the other side. This is easy to fuel inject, because the manifold has a dedicated port for each cylinder. The older inline engines combined the exhaust and intake manifolds into one to help warm the intake passages and prevent fuel dropout. This is a PIA for injection because two cylinders share an intake runner (Siamese), and there is usually an overlap between them on the intake valve openings. My engine operates at a maximum of 1500 RPM, so that equates to 40 milliseconds (ms) per revolution, or 10ms per cylinder, even though two cylinders are not firing during that cycle. I need large enough injectors to get the fuel in, shut it off, get ready and inject the adjacent cylinder.

How much endplay does the CAMSHAFT have, and how is it controlled?

If the camshsft is bouncing back and forth at all, as you know, timing will be changed by the relative movement at the helical gears both at the cam drive, and at the cam-distributor drive.

(I ASSUME the timing gears are helical-cut.)

Interesting to see and hear about this project. But I don't think I have read what HP gains if any you have over a stock original MH44. Have you tested this tractor before and after the conversion ?