I'd be interested to hear about the other options.
I'll list a few of the options I'm thinking/reading about.
Keep in mind that my needs are very different than most.
I want increased mileage, extreme reliability, and simplicity (no ECU, no electronics preferred). I expect to take this JKU 150k miles +
It must be able to happily run extremely high sulfur diesel, and likely low quality, "dirty" diesel. Bio is a plus, not a must. I will have extensive filtration to help with longevity.
Having it drive similar to the stock 3.8 is fine, I have zero interest in >250hp or >300 ft lbs. though I expect more torque down low will make it easier to cruise at 60mph up hills, etc.
A cruise speed of 60 is great, I don't need anything over 70mph.
Emissions, registration and rules, etc. are of no concern. It's not an issue where I live.
For all of these, I want a stick shift. I much prefer sticking with the stock 6 speed NSG 370, so there is no shifter, transfer case or drive shaft mods.
I expect my JKU will be heavy with everything else I plan on adding, which will impact potential mileage. I'm not interested in over 2.5 inches of lift. Likely will run 33s,
maybe 35s
random order
Izuzu 4BDx
3.9 ltr, 4 cyl. Likely fits. Heavy. All mechanical. Not great mileage. No adapter exists, but it's well-known and I'm sure it could be made.
I think 3.9 ltr is overkill for the JKU and my needs.
Merc OM606 Turbo
Inline 6, 3.0 ltr 178hp, 243ft.lbs, should drive similar to the stock 3.8. Many people swap the Injection Pump from the OM603 onto it to make it all-mechanical. Good mileage. Has been adapted to the AX-15.
Another company is working on adapters for all the OM60x engines, and would make me one for a NSG 370.
Might be too long (at 31 inches), and would likely have front axle/oil pan issues that need resolving with something creative (oil pan from 603? rear sump? different oil pickup?)
Extremely reliable.
Merc OM605 Turbo
Same as above, minus one cylinder for inline 5, 2.5 ltr. 148hp, 207 ft. lbs.
Might do some minor tuning to bring it up to ~170hp, ~240 ft. lbs. so it drives like the 3.8 (It's common to build them to over 300hp, but I don't want to go crazy - I want reliability)
Hopefully short enough to fit, and avoid the oil pan/front axle clearance problem. Still trying to hunt down exact measurements.
I like the Merc diesels as they are relatives of the "million mile" engines, and are extremely common (parts, service) in many parts of the developing/undeveloped world.
Also, with twin overhead cams (chain, not belt driven) and 4 valves a cylinder, they are likely the most efficient all-mechanical diesels ever made, which appeals to me.
VW M-TDI
Lots of VW guys modify the TDI engines to be all mechanical, so they have absolutely no ECU.
The back of (almost) all VW engines are the same, so I could look for one of the 2.5 V6s, though I read they are not great for mileage.
HPA have a kit to bolt them up to the NSG 370, engine mounts, etc. etc.
I'm trying to investigate how the engine will handle high sulphur diesel - I can't find much on this yet.
Might be a little underpowered for the heavy JK, without an ECU it's harder to tune.
Cummins 4BT
I'm really not interested because I think it's too heavy and loud, with too many vibrations to make it enjoyable to drive for hours and hours.
I think 3.9LTR is overkill for the JKU and my needs.
The only reason it's interesting is because it's becoming very well "known", so it's a well trodden path. Reliability should be no problem.
Would require an NV4500 5-speed, which is bigger and heavier. Unsure how much lift is required.
Thoughts? Suggestions?
What else should I research?
Thanks,
-Dan
