I've been thinking about an engine swap in my LH85 cabover Hiace truck for a while now. The reasons will be obvious if you've ever driven a truck with an L series engine. They're painfully slow and gutless, especially when you add even the lightest of campers.
I started out by slapping a turbo on the original motor — and to be fair, it actually woke the truck up pretty nicely in terms of power. But the install was a pain. The tight cabover layout combined with the manual shifter linkages made the packaging super awkward. Everything felt crammed, and it never quite fit right. In the end, the whole setup pushed the little engine past its limits — ended up popping it and losing compression on cylinder #4. So yeah… good power, but not worth the headache or the blown motor.
Looking back, I kind of wish I’d just gone straight to an engine swap from the start. Would’ve saved some time, money, and a blown motor. There’s basically zero solid info out there on engine swaps for these cabover trucks — it’s a bit of a black hole. That said, I did find a few threads about folks going from L series to 1KZ or 1KD in Hiluxes, and a couple of mentions of it being done in vans. Nothing detailed though.
This project is way outside my comfort zone, but I’m jumping in anyway. Figured I’d document the process here — partly to give back and maybe help the next person, but also to get feedback and guidance from those of you who’ve been down this road before.
Life’s a little hectic right now, so updates might be a bit slow, but I’m committed to seeing this through.
Why the 1KZ?
There's no perfect engine, each choice has pros and cons, but the 1KZ is far from the holy grail of engines. I was not looking for crazy horsepower — just wanted to go from “ultra-slow” to “normal slow”. My main criteria:
Engines I Considered:
1KD
1KZ-TE
Mercedes OM605
TDI
Toyota B series
Why I Picked the 1KZ:
Checks most of my boxes:
Sourced a later-model Hiace 1KZ with the factory water-to-air intercooler (bonus!) for a very reasonable price.
I also have a mech pump and high-flow turbo from KRAE on order, planning to keep it mild — focus is on reliability and efficiency, not big boost.
Also will be doing:
Build Plan:
Breaking it into phases so I don’t get overwhelmed:
I started out by slapping a turbo on the original motor — and to be fair, it actually woke the truck up pretty nicely in terms of power. But the install was a pain. The tight cabover layout combined with the manual shifter linkages made the packaging super awkward. Everything felt crammed, and it never quite fit right. In the end, the whole setup pushed the little engine past its limits — ended up popping it and losing compression on cylinder #4. So yeah… good power, but not worth the headache or the blown motor.
Looking back, I kind of wish I’d just gone straight to an engine swap from the start. Would’ve saved some time, money, and a blown motor. There’s basically zero solid info out there on engine swaps for these cabover trucks — it’s a bit of a black hole. That said, I did find a few threads about folks going from L series to 1KZ or 1KD in Hiluxes, and a couple of mentions of it being done in vans. Nothing detailed though.
This project is way outside my comfort zone, but I’m jumping in anyway. Figured I’d document the process here — partly to give back and maybe help the next person, but also to get feedback and guidance from those of you who’ve been down this road before.
Life’s a little hectic right now, so updates might be a bit slow, but I’m committed to seeing this through.
Why the 1KZ?
There's no perfect engine, each choice has pros and cons, but the 1KZ is far from the holy grail of engines. I was not looking for crazy horsepower — just wanted to go from “ultra-slow” to “normal slow”. My main criteria:
- Ease of swap – first time doing something like this.
- Keep it diesel.
- Toyota power only. Just seems wrong putting anything else in this rig.
- Compatible with my R-series trans.
- Mechanical over electronic. Simplicity rules, no complicated electronics.
- Reasonable power and reliability.
- Compact enough to fit the cabover engine bay.
Engines I Considered:
1KD
- Great motor, good power, solid rep.
- Small footprint (same block as 1KZ, however I think the head is taller which could potentially be an issue)
- Bolts right up to R trans.
- BUT… common rail, needs electronics. This would significantly increase difficulty of swap.
- Also pricey and rare in the States.
1KZ-TE
- EFI from factory, but easy mech pump conversion via KRAE in NZ.
- Less power than 1KD but still plenty. 120-130 hp at wheels seems like a sane reliable goal with intercooler, adequate exhaust and intake.
- Very similar footprint to the L series. Same width and length, only slightly taller.
- Direct bolt-up to my R trans with the right bellhousing.
- Availability and price is very good
- Known weak point: cylinder heads can crack if cooling system is neglected. Still IDI turbo.
- But with maintenance? They hold up.
Mercedes OM605
- Tempting. Mechanical injection, solid power, diesel cult status.
- Downsides: Not Toyota. Expensive. Long. Hard fit (probably too long and too tall). Adapter needed for R trans.
TDI
- Small, compact, big owner community, lots of info out there, lots of parts out there.
- Not Toyota, though. And smaller displacement could be stressed in a heavy rig.
Toyota B series
- Legendary reliability
- Direct Injection options
- Unfortunately too big, too heavy, too rare, too expensive, too complicated to install
Why I Picked the 1KZ:
Checks most of my boxes:
- Easiest option to install.
- Toyota badge.
- Mech pump option.
- Plenty of power for my needs.
- Simple, reliable, and fits the space without major re-engineering.
- Not perfect but I think it's a good OEM+ option
Sourced a later-model Hiace 1KZ with the factory water-to-air intercooler (bonus!) for a very reasonable price.
I also have a mech pump and high-flow turbo from KRAE on order, planning to keep it mild — focus is on reliability and efficiency, not big boost.
Also will be doing:
- Injectors
- Glow plugs
- Timing belt
- Water pump
- Full gasket set and general freshening up
Build Plan:
Breaking it into phases so I don’t get overwhelmed:
- Engine mounts & general fitment
- Packaging – shifter linkages, radiator, etc.
- Engine maintenance
- Final install
- Plumbing & wiring – coolant, intake/exhaust, alternator mod (external regulator to internal, sensors, etc.)
