[jcgrillo]

Exactly. Electronically controlled unit injectors are expensive--like 10x the price of mechanical ones. They're super cool, they can produce like 10 separate metered injection events per cycle. This is great for efficiency, noise, emissions, etc. But I can rebuild mechanical injectors with a bottle jack pop tester I made from $100 worth of parts and a bench vise. There's no wiring harness, no computer.. If the injector is getting fuel, has decent spray pattern, and is popping at the right pressure I know for certain the fuel system is good. With an electronic common rail system I need some expensive proprietary computer equipment to diagnose it, and there's no way I can build a test bench to rebuild those injectors.

[LeifCarrotson]

You can't build a test bench to rebuild current OEM's electronic common rail injector systems that rely on expensive proprietary computer equipment, but there's no reason that has to be the case.

With a $20 CAN transceiver, documentation and/or config files from the manufacturer, and a bit of Python or something, you could absolutely bench test those electronic injectors. You might even be able to pick your injection events and adjust the metering, supporting the equipment as it ages. I'd love to see Ursa Ag put in a Megasquirt engine controller [1] or Proteus [2] or similar. You can run TunerStudio on a Raspberry Pi and show it on a touchscreen on the dash.

It's possible to build user-friendly, inexpensive and open engine and vehicle controls. You don't need to have zero electronics to not have locked-down proprietary electronics, you just need to build the electronics in the right way.

[1] https://diyautotune.com/products/ms3357-c?_pos=2&_fid=69f494...

[2] https://rusefi.com/index.html#proteus

[jcgrillo]

Controls are one thing, but there's also the problem of generating 20k psi of oil pressure and some thousands of pounds of continuous common rail fuel pressure to actuate the injector. Compared with older MW, M, P, etc. styles it's a whole different beast. Also, we're talking past each other a little--I'm talking about diesel injectors, you're talking about otto cycle equipment ;)

[amluto]

Surely there’s room for a middle ground. There are plenty of 1990s-era engines that were excellent designs, had no meaningful connectivity to anything except their own ECUs, and could be produced new for not very much money. Some of them were quite modular, too — I know someone who took the drivetrain out of a salvaged Honda Civic and built an entire car (with no resemblance whatsoever to a Civc) around it.

If a tractor with a clean-burning, efficient $7500k engine could be purchased and were designed around the theory that, in 20 years or so, the owner could reasonably quickly replace the entire engine (with a first-party or aftermarket solution), would that be a good solution?

The common tech that has solved these problems nicely (IMO) is network transceivers: SFP and similar modules are built according to multi-source agreements. They contain all kinds of exotic tech, and they are not intended to be serviced at all, but (unless your switch or NIC has an utterly stupid lockout) you can pull it out and replace it with an equivalent part from a different vendor in seconds, and those parts can be unbelievably inexpensive considering what’s in them. (Single-mode bidirectional 1Gbps transceivers are $11 or less, retail, in qty 2. This is INSANE compared the the first time I lit up a 1Gbps SMF link. To be fair, this particular tech may require one to replace both ends if one fails, but if you can spare a second fiber, the fully IEEE-spec-compliant interoperable ones are even less expensive.)

[jcgrillo]

It's not the craziest idea. A tractor is basically just a big hydraulic pump driving a bunch of linear and rotary actuators (commonly called "motors" and "cylinders"). Especially if it's got a hydrostatic transmission. If you design it in such a way that it's relatively easy to adapt different clutches and bell housings, maybe with a little driveshaft and u-joint between the clutch and the pump, you could theoretically accomplish something like this.

However one major sticking point is that (often.. maybe always?) the engine block casting is actually a structural component of the tractor "frame". Unlike e.g. a truck that has its driveline mounted between frame rails, a tractor's "frame" is its driveline . So this might add quite a bit of complexity and cost.

[cineticdaffodil]

Eh to henerate a decent nozzle takes some precision lazer drilling (e.g.trumpf) or edm drilling (e.g posalux)and some grinding + a quality test bench. Its not that easy having good lowtech solutions either.

[jcgrillo]

Yeah you're definitely gonna want to purchase nozzles. They're extremely precise and manufactured to very high tolerances. I've rebuilt plenty of 30+yr old injectors and haven't yet been unable to find newly manufactured or new old stock nozzles though.

EDIT: I did have some nozzles bored out a little bit once by a shop with EDM equipment. Terrible results, not worth it.