1988 Isuzu Trooper diesel conversion

And here is a shot of the current state of the engine bay. Messy, but starting to come together...

Not much fabrication here - the stock diesel Trooper airbox, filter etc. all bolt in without hassles. The flexible rubber intake hose fits with a little trimming. I did have to cut a small notch in the airbox cover which allowed it to rotate toward the engine a few degrees in order to fit the hose correctly.

The radiator used is a unit from a 1986 diesel Trooper. The hose inlet/outlet are on opposite sides of the radiator (as compared to the radiator from the gas Trooper); the core is also thicker and the tanks are larger, it's much more robust overall. The radiator and shroud are bolt-in items, no modifications needed to mount to the chassis.

The upper radiator hose, shown above right, is also from a diesel Trooper. It required minor trimming to fit.

The lower hose (above left, shown from underneath, with the near end being the engine end) was problematic. The engine-side inlet is larger than the outlet on the radiator and is located slightly to the side of the outlet. I tried to find a hose that had the curvature I needed which also changed diameter at some point, but I was unsuccessful (not to mention annoying to the fellows at the parts counter). Additionally, the distance is too short to use any sort of universal flexible hose.
I decided to have the radiator modified and have the outlet enlarged to match the inlet tube on the engine. With this done, I found that Gates hose #22364 has a curved section that fits perfectly (after removing a 90-degree bend at one end). According to the Gates site, this hose fits a 1998-2001 Ford Ranger or Mazda B2500 pickup. I am not sure which hose it is, or which engine it fits, but these trucks are common so I don't anticipate any problems finding spares in the future.

These photos show the pump connections and pressure line routing for the power steering system. The new bracket and hardline are visible in the photo on the right.

The power steering system was completed using a custom flexible pressure hose, a fabricated bracket to hold it in place and a new hardline to connect the pressure hose to the steering sector.

The pressure hose uses the pump end that came with the engine (although this is the same fitting the gas Trooper hose uses, just not as long and full of curves) and the opposite end is the same as the gas Trooper hose as well. I believe this hose is actually a Rodeo hose which has been modified at the pump end, as the Rodeo hose pump fitting looks to be correct at first glance but is actually different in inner diameter and will not work with the Trooper pump. Thanks to Jerry Lemond for the hydraulic fabrication work and consultation on this stage of the project. As far as I can tell, the diesel and gas power steering pumps are identical save for the pulley.

The pressure hose then travels down along the side of the radiator and is secured by a bracket I fabricated. The connection is the same as the stock gas Trooper and uses the top half of the factory bracket to retain the hose. The lower half of the bracket is a piece of angle iron. The bracket attaches to the frame on top of the bracket that holds the power steering hardlines that run along the frame, below the radiator.

The new hardline was made from a length of 3/16" brake line (I believe that's the dimension - I matched the old hardline I removed from the truck) which was bent to connect the pressure hose to the sector. The fittings on the ends were taken from the old hardline and re-used. It was time-consuming to get the bends just right, as the line is fairly short and has to be pretty much perfect or the threads won't start correctly in the sector or at the pressure hose.

The 1986 diesel Trooper uses the fluid return line as the cooler and this line is looped from the reservior to the sector, running along the frame below the radiator. The gas Trooper cools the fluid using the pressure line, as the pump is on the passenger side of the engine bay and the pressure line has to run across to the opposite side anyway. I removed the old pressure line and so was left without a cooler line. I decided to install the diesel cooler line, as it was the easiest solution (it bolts right in, no modifications needed).

The reservior was connected to the pump using a length of silicone heater hose, which is oil-resistant. The return line (below the radiator, as factory for diesel Troopers) is connected to a length of transmission oil cooler line which runs from the hardline up to the reservior.

If I had to do this again, I would modify the pressure hose end to match the return line from the gas Trooper, as the gas design reservior-to-sector hose screws into the sector. This way, I would be able to eliminate the bracket and hardline I fabricated and attach the new pressure hose directly to the steering sector. This would have saved hours of work.

Here is a photo from underneath which shows the new clutch hardline routing, new bracket and stock flex hose used to connect the slave cylinder.