I always found it fascinating, these overhead shafts would run in wooden blocks as bearings, and pretty much last forever. Any wear would be on the steel shafting, and not the wooden bearing blocks. Old engineering shops too relied on one big central electric motor turning overhead shafting, each drive pulley had a free wheeling pulley beside it, a fork would jump the flat belt from one to the other to activate the selected machine. I  remember the punch had a huge flywheel that took some dexterity to get to speed without squealing the belt, and causing it to derail completely.  I have no idea on the frictional losses incurred, but it was a common way to power a factory back then. Unrelated, but when I was a kid, I watched the local inventor sit in the back seat of his fordson van, and drive across the Ormondville train viaduct. His theory was that if a flat belt will center itself on a convex pulley, then a convex car tyre should stay centered on a flat railway track.  We admired his conviction, he survived, we applauded , the railways fined him for trespass.

Just to expand on the process if anyone tries this. The alloy was cut 1 inch wider than the journal, bent roughly to shape and squashed into the big end using a 2 inch wooden dowel to force it into the shape of the big end hole. The sides are then peened over the sides of the big end to create the thrust faces. The shells then were filed to shape , the ends made nearly  level <crush> with the big end faces between cap and rod. The rest is very time consuming ,to get a good contact surface, using emery , files, and a sharp wood chisel to scrape the high spots
To repair a crank journal its not sufficient to just remove scoring, it also must be round, with as little taper as possible. Initially use strips of emery paper to remove as much damage as possible. Then tackle the finish.
The easiest way here is to make temporary steel shells to fit the rod, these become sacrificial to complete the process of final grinding with valve paste. Again, shims between cap and rod are removed as the journal  decreases in diameter. When there is no more binding throughout the rotation, job is done.
Handy Hint...... BRAZE THE OIL DIPPER TO THE ROD CAP.....

I tried this years ago, decided not worth the trouble. The amount of heat in the exhaust is reduced rapidly under partial load. This is because a diesel always ingests a complete cylinder full of cold air,  and under partial loading, the injection of fuel is just a small part of the complete power stroke, the excess air steals your heat basically.  Using cooling water to preheat the water arriving at a  normal hot water cylinder is a useful addition, but usually requires extensive plumbing alterations and can feed vibrational noise into the other parts of the dwelling. My Lister uses a car radiator mounted through the wall into my workshop, electric car fan ,so does take some chill off during winter. If your engine runs full load for lengthy periods, it may be worth doing, but for me, not.

I am gunna say its low fuel pressure. Because it starts and runs well, its not compression or injector. When trying low  speed, the fuel pressure drops causing fuel to just dribble into the cylinder without igniting. After several non firing strokes, the raw fuel vaporises from cylinder heat, causing ignition on subsequent compression, then the cycle continues.
 Years ago, a dude fitted a new fuel pump to his toyota Hilux. It needed a tow start, and then would run hot with no power. Turns out it was injecting on the intake stroke, burning vaporised fuel rather than atomised fuel., so this is certainly possible.
 Injector pumps should have constant pressure, and variable quantity. Veggie, I would loosen the injector pop pressure to see any change.... if its a fuel pressure problem then it will have little effect. Mind you, it has little effect anyway that I have seen. Setting the rack at a low speed and testing removed injector spray by cranking may point to the problem.

my 3/1 struggling cold on vege oil
https://www.youtube.com/watch?v=Hc3dXaBPpvw
theoretically a twin should run slower having twice the firing strokes,  a heavy flywheet model would run smoother at low rpm. Vege oil i suspect is possibly more reluctant to combust than diesel or kero, so possibly skipping a few bangs here and there. Also compression pressure would play a role too.

Hello Bruce. We are lucky in having a temperate climate.  I never did like milk, more into admiring  the containers it comes in these days. Maybe I was just  too young back then to really appreciate the wondrous things in life.

Take a 20 liter plastic oil drum, whack 2 x 2 inch holes thru the top. Insert a length of 2 inch PVC pipe into 1 hole to the bottom, cut the bottom end at an angle to allow and guarantee an  air gap. It just needs to exit the top of the container a few inches, this is the air inlet. Another 2 inch PVC pipe is inserted into the other hole  a few cms and is glued to keep it at the top well above the water level. This connects via flexible tubing to the Lister air inlet manifold.. A small overflow hole is drilled around 1/2 to 1/3 the way up the container to prevent the water overfilling. A third small diameter pipe is inserted thru the container top to supply a slow trickle of water into the container. I used 3/8th clear tubing for this.
Thats all there is to it. The vacuum pulled by the inlet stroke will suck air up thru the water giving a saturated air density into the engine, easy, quick with no moving parts. I got this idea by observing that cars seem to run smoother on rainy days. Keep the pipe to the engine intake fairly  short and use wire reinforced pipe to prevent suck in.
Because its cheap and easy to do, just cobble something together and try it first before making a good permanent one. I think water injection  works similarly to when throwing water onto an oil fire, the heat turns it instantly  into steam that shatters the unburned oil droplets and atomises them further causing total  chaos and mayhem. Even a petrol engine benefits from this, and I wonder why manufacturers havent seemed to follow this up. Piston WW2 aircraft used it frequently to maximise the HP and increase efficiency.  Given enough water, and it takes a frightening amount, a diesel will stop the detonation knock and  will run as smoothly and quietly as a petrol engine.

The real killer i found with lead acid is that final 20 percent or so charge, where the battery will only accept a fraction of the bulk charging current,without excess bubbling so this finishing charge takes many many  hours to complete.
 In real life, the bank is being continuously cycled, charging and discharging at the same time, the final top up never quite happens.... so the things will eventually sulphate regardless..... i know, pessimism right there.
.Forcing wont work, bubbles and fizzing is what sheds plate material. This i think is lithium's big advantage. over lead acid..... or at least they promise this.