Yanmar injection pump modifications

[1130Lilshive]

If you are not worried about rules and have a machine shop just adapt an inline pump on it, Bosch A pump or whatever. This has been done for years. It has been about 10 years but was buying 3 cylinder A pumps on ebay with 8 or 9mm plungers, if I remember right, pretty reasonable.

The guys who got serious with the 78 Yanmars split the blocks in half between the 2nd and 3rd cylinder if I remember right. Kubota"s block & bottom ends are built much stronger but you need to convert to direct injection.

You may also need a charge pump capable of something like 40-50 psi, at least you do if sticking with a cambox style pump.

Ive thought about adapting a pump on it but I got to thinking about firing order and getting it time with the gear train but definitely I'll look in to it, how much do you think a cam grind would help me? I get so many ideas but I'm use to alcohol v twins this is a whole new world for me.

 

[Bigkrank]

I have found you must go to water injection with a cam grind if you are making good power. You will likely need to check & modify other things when going to a cam grind. I quit answering my phone years ago when guys were trying to put in custom cams and were too stupid to check everything else out.

Of course the cam grinder was telling them they could just put it in and go. Dummies couldn't figure out why the rocker rail nuts wouldn't stay tight.

 

[1130Lilshive]

Ok I think I have the fuel part of all this figured out, now I just need the boost to burn it. I had two ideas spring to mind and of which would be to bypass the governor by hooking up a throttle cable set up directly to the rack. (very carefully of course I know there fragile) if I could get it up to 5,000 rpm (4,400 makes 10-12 lb) I should be around 15-20 lbs of boost which would be ideal. (any above that wouldn't gain me much without a intercooler) would it still run properly if an adjustment screw was used to set the idle? Idea number two is to have a cam ground to move more air at the rpm I got. (assuming a cam could do that) I'm not sure if a cam grind could increase boost numbers or not. Or here is another one I just thought of, what if I where to drill a 1/4 inch hole in each governor weight to lighten them? I still have about a 1/4 inch of travel left on my idel screw so it should still idel down. Would I have to change springs as well? Any help is greatly appreciated

 

[clemsonfor]

5,000 rpms!!!

How long do you expect this thing to last?

 

[4get gto]

I'd love to see that run! Don't know how close I'd want be. :firecracker:

 

[California]

Is a scattershield (for the flywheel) included in the plan?

 

[kenmac]

Is a scattershield (for the flywheel) included in the plan?

LOL, Not a bad thought. That's a lot of mass turning 5 K RPM'S....
I use to run a shield on my drag car (auto Tranny) It was mandatory !

 

[chriswheeler]

I've always wondered how the 3T84 can be used with so many different tractors from the YM2310 all the way up to ( at least I seam to remember ) the YM3810 and have the same engine output such different HP's across that spectrum ?? Yes, I do some of them do use a turbo, some don't. The answer to this would be timing and fuel pump output + injectors ?? Exactly what Yanmar is doing at the factory to the different models of this same engine to raise and lower the HP's would be interesting to know. I think the max rated RPM in all cases is less than 2800, but I think the answer to what you are trying to do is somewhere in the answer to that question. @ 5000 RPM, I hope you have several spare engines to scatter in your experiments, good luck. I saw the end result of a Cat V12 generator engine that went over speed until it exploded, very dangerous for bystanders, could have killed someone. Didn't kill anyone, but sure messed up the room.
Chris

 

[pmsmechanic]

5,000 rpms!!!

How long do you expect this thing to last?

2 liter VW TDI's are redlined at 5-6000 rpm from the factory. 5.9 Cummins used as truck puller engines hit 5000+ rpm on factory stock bottom ends. I don't know how reliable a Yanmar is at those rpm's but it will be interesting to follow this thread and hopefully find out.

 

[Bigkrank]

I made a jig to drill & lighten the weights on Kubota governors. Also used heavier spring. I would start there first before hooking directly to rack, you will have idle problems.

We were turning more than 5000 with 30-45 lbs of boost. Never saw a Kubota scatter myself, Yanmars not so much but with direct injection we are talking insane power & torque. Course stock parts will not work here. There are videos of these tractors on the internet.