adventures in converting a d4 to diesel pilot engine

so after the pilot engine went rattle stop and shattered half the teeth off the mag gear and bent the shaft. I wanted to make it electric start pilot as that is rare as hens teeth, I thought for simplicity make it diesel. one fuel type. no fuel to go stale.

well that meant i had to get a 80 tooth custom idler gear made that was $600bucks. i also got a bushing made to adapt the original crank gear out of the pilot engine to the new diesel engine's output shaft keyed to the gear and the output shaft. the idler gear rotates thanks to a needle roller bearing on a shaft mounted in clamp blocks that can be adjusted of the base plate with shims to set backlash for the pinion shaft gear.

I also made a baseplate to mount the gear from and blank off the coolant gallery in the bell housing from 10mm plate. the engine will also mount to a 6mm plate that bolts to the base plate and can slide for adjustment of backlash on the gears.this plate will also pick up the sae bolt pattern on the side plate of the motor.

the main engine intake will be drilled with a bung welded in to take a heater plug set to run on a timer relay.
had to relocate the hydraulic lines to clear new motor, so there's a few hundred bucks. using sae100R2 hose is quite cost effective and field attachable fittings mean a hose failure is easily repaired. the same hose also works with the original code 61 field attach fittings used by cat.over 700 bucks in hose, fittings and high pressure tight welding.
stripped out the factory generator made a longer shaft so it is now a adapter to drive a 1 wire alternator this will charge the battery and provide power for lights,radio and fan to entertain and cool me on those hot days also power the electric start for pilot. longer shaft has a taperlock pulley to get a easily changeable belt drive to the alternator also fitted new bearings and oil seals to generator body.

the new motor is 6hp single cyl 4 stroke diesel with electric and recoil start. so if the battery is flat or the starter dies can still start it.

still have to work out a cover for the gear train to keep it clean and fingers away from spinning things. will also need brackets for the main intake, a blanking plate for the head. adapter to feed the pilot exhaust into the factory spot and wire everything up. also going to fit a racor water separating pre filter. much easier to change a spin on pre filter than the factory filters will also give better protection to the engine. photos to follow. have to wait till i go back out to the machine as its currently half an hr drive away.

Trainzkidd88- quite a project, keep us posted. I was in able to view your attachments. Anyone else with that issue?

Keep safe and have fun-

you actually have to open them.works fine for me but spose it depends what browser you use and what settings you have configured

hindsight is 20/20 i have made a big project and a expensive one.
shush we wont tell mum how much dad and I have spent on it.(well mainly me as it's my idea)
the cheapest bits are the laser cut plates. i hope to have it relocated to home in the next 3 months. so its easier to work on. have to stand up a roof to keep it under first.

TK88, I thought I was the only one to make mountains from mole hills, good to see im not alone now, yes it does make sense single fuel etc, yes a big task but im sure it will work well once set up right and with a few adjustment's it will be good, yes bring on the pictures im sure some ideas from it will travel

I was thinking of using my old Harley engine as a pony start. 🤣😂🤣😂 That way I could kickstart the thing. 🤣😂
Better yet drop the Harley engine altogether and just use the kick starter 🤣😂🤣😂 . That's funny there ... you'd have to stand on the hood to start the beast.

Im not sure which one would make the most noise under load

i am only re-jigging an idea another member from the states had used on a d2. the original cost estimate has quadrupled. especially thanks to unforeseen costs like the hydraulics rerouting. while I can weld I don't trust my welds at 1200psi working pressure so that had to be professionally done. same with the machining when you don't have a lathe. i plan to change that soon.

thats also part of the job fitting a muffler to the main engine. with the scrub canopy she makes a bit of a racket as the exhuast echos under it. it also chokes you on fumes if the wind is blowing the wrong way.

I added a muffler to the pony - that makes a massive difference to the "serenity" of start-up : )

Neil, what kind of muffler did you fit? my D2 pony has the side pipe on the RHS is this the same as yours or do you have the vertical?

Hi Busso, I just picked up a generic muffler with an inlet large enough to slip over the pony exhaust outlet. My 3J has the exhaust pointing horizontally out the right/passenger side, and the 5U has the vertical outlet poking up through the hood. The muffler slips over both. I only use it when starting, otherwise I take it off and stow it. I don't clamp it on - just slip it over. Still makes a huge reduction in noise. I'd recommend any muffler you could get your hands on - prefer a muffler over a resonator (straight through) for max noise reduction. My muffler is about 15" long and about 10" diameter. Check with your local custom exhaust shop because they sometimes have take-offs lying around for $20 - that's where I got mine from. But looking online, Walmart's advertising a Walker 18150 for a Toyota Corolla that would probably work. Weld a handle on it so you can hold it without getting burned and you'd be golden for $50