Jima Y385T powered Mazda Pickup

[danthefamilyman]

I bought it on Ebay about 2 years ago. There was a guy that was importing them from India or China and he had a storage of them in Portland Oregon (about 60 miles from my home). They are really hard to get now, I guess because they are not EPA rated. I have read that running on bio-diesel the engines exceed EPA standards, but I have not found any more for sale in the Portland area. The engine is a blast to start, (hand crank) and just ticks along at 450 RPM. It sounds like an old grandfather clock, very relaxing to watch, with the open rocker arms and pushrods going up and down. I used a 2" wide cogbelt (timing belt) to drive the 5 KW Generator head.

 

[RonMar]

Cool, I have been building a 6/1, 5KW genset in my garage since December, and it is just about ready for installation in the generator shed. Mine is just for backup but I am employing a heatexchanger to recover the cooling system heat into my domestic hot water. About the only thing I will be missing in a power outtage will be the oven and the electric dryer It's miserly fuel consumption also means the fuel stored will go much further.

Thanks for posting the stress test info on the diesel truck engine. Good to see it appears to be surviving the installation.

 

[danthefamilyman]

I have been asked several times how the flywheel was balanced. I wanted to post pictures of the process but did not take any pictures when I did it (I was having too much fun) so I guess I will just have to describe it.

It is based on the fact that two rods at 90 degree angles to each other (one on top of the other) have very, very little contact area and thus very low rolling resistance, allowing for very fine static balancing.

How it was done:
During the machining of the flywheel, while it was still in the lathe, the center hole of the flywheel was set up to within .0001 of the crankshaft bore. This allowed the center hole of the flywheel to be used as true dead center.
I then machined a shaft 8" long with a .0015 taper from one end to the other and sized it so that it would be a slight press fit when inserted into the flywheel center hole. So, I now have a fly wheel with a shaft sticking through the center of it (shaft is sticking out of both sides)

Next: I placed two pcs of 3/4" Thompson Rod (62 Rockwell C scale -case hardened,) on steel risers about 6" apart from each other that alllowed the flywheel and shaft to be set on them and rotate until the heavy side was on the bottom. Using a machinist level I adjusted the two pcs of Thompson rod until they were level with each other.

Then:
I placed the flywheel and shaft on the Thompson Rods and allowed the flywheel to rotate until the heavy point was down. I then made a hanging wire pointer out of brass wire that hung from the tapered flywheel shaft. The wires point, pointed to the place on the flywheel that I was to drill a 1/2" diameter hole in the flywheel to remove material.

This process was repeated 8 or 10 times until the flywheel no longer rotated when placed on the two pcs of Thompson rod. In fact at the end of the process I could get the flywheel to rotate either direction just by blowing on it. I say it was within a quarter of an ounce, but in fact it was probably much closer than that.

This is the simple explaination of how it worked, there is much more to it.
The surface finish of the rods are important, the taper of the flywheel shaft is important, accurate machining and good dial / digital indicators can affect the results. I used Thompson Rods because they are very hard and have a good surface finish, I used Steel as the flywheel shaft and polished it before I used it.

How did I know how deep to drill the holes in the flywheel?
I machined a 1/2" diameter shaft of cast iron and made various lenghts of them. I would attach them to the top of the flywheel at the pitch diameter that the hole would be drilled. The length of these shafts would then be the depth of the hole that would be drilled into the flywheel.
I did one hole at a time, because as I would drill each hole location of the next 'heavy spot' would change.

It ended up with five 1/2" holes drilled into the flywheel. hole number five was only about 3/4 of an inch deep. It took 3 or 4 shots at the final hole (each one just a fraction deeper) before the flywheel no longer moved when supported between the Thompson Rods.

This was a modification of what an old journeyman machinist taught me when I was serving my apprenticeship. We used to have to balance our grinding wheels on our surface grinder before using them so that the wheel balance would not leave marks on the tools and dies we were building.

I hope this helps explain what I did. I wish now that I had taken pictures. It sure worked out well...there is no flywheel vibration at all engine speeds.

Thanks,
-Dan-

 

[danthefamilyman]

Correction:
I ended up with seven balancing holes in the flywheel when it was done. (After two years I just about forgot) The whole process took about 4 hours, but time went by real quick (it was a real, real fun to balance the flywheel!!!!)

Thanks,
-Dan-

 

[RonMar]

I dynamically balancd mine. Removed the head and crankcase door and spun the crank, flywheels, piston and rod up as close as I could get to the 650 RPM running speed and adjusted counterweights on the wheels untill the movement of the frame was at a minimum(under .005" for-aft) the whole assembly, engine, generator and frame were up on 3/4" pipe rollers and I could easilly move the 1000# of weight with the tip of a finger. I re-assembed the engine after balance and while it was still on the rollers, ran it with 2KW of electrical load on the generator. For-aft movement was about .010"-.015". It will be bolted to a 1300# block of concrete, but it runs happily under 3KW load just setting on my garage floor.

 

[Flyhiflylo]

Cool truck.

 

[BTDT]

Nice setup.. Where did you find the engine?

Soundguy

I've been debating trying to find an old unit out of a refrigerated trailer, might be able to find a salvageable engine there, but don't know what it would cost.

 

[danthefamilyman]

I found the engine brand new on Ebay. It came from Coldwater Tractors in Washington State. I paid about $900 -$950 for it.

 

[Danish]

Hi Dan,
Nice and creative project!
I had to register to ask, if you have cancelled the idea of turbocharging your Y385T?
I wanted to find out if anyone has experience on this matter.

How is the engine holding up so far?

The word is, that a Jinma 254 here in Denmark reached approx. 7,000 hrs. before the engine was replaced. The engine was replaced due to a broken valve. The damage was "minor" but the owner chose to replace the entire engine, without knowing at the time what had caused the bad noise at start attempt.

I bougt my tractor at an auktion as "unused". I wasn't able to see it before I bought it, as I was at sea at the moment.
I got it cheap, though. When the tractor arrived, the engine oil was heavily contaminated with water. Initially I suspected a cylinder liner O-ring, as I did not know the engine is fitted with dry liners. It turned out, that the engine block was cracked on the way from China, due to none or too little anti-freeze.
I ordered a new engine (at least I thought), but recieved only an engine block. So what the h..., I replaced the block. The tractor has now been doing well for 45 hrs since then, but sometimes I miss the turbo whine, and a bit more power.

When the tractor was exploded, I dismantled all transmission and gear covers and flushed it all out with diesel oil. Amazing how much dirt, paint chips etc. I was left with.

//SC

 

[SPIKER]

hey Dan I hadn't heard anything new, how has it been working in light of high fuel costs & all???

Mark M