Thanks for the info. I have read of people pulling out engines out of NPR trucks, including 4JB1-T. There is a place in Phoenix that is a salvage oppertation for Isuzu commercial trucks and they are searching their inventory for me. The 4JB1 was replaced by a lager series of engines in the NPR, so maybe we'll see. However there still is that little problem of the transmission. Is the tranny for the 4J too torquee for the 4EZ tranny I have in my truck. Appearently you can get a plate fabbed at a machine shop that retrofits about any bell housing to a transmission (within reason). Anyway as fuel prices keap rising and the politics of oil escallates (see China) I really want to get of the oil dependency and start making my own bio-diesel.

Not sure what you mean here exactly, but the 4JB1-T transmission has got a different bellhousing than the 4ZE1, although they seem to be identical otherwise. In fact, the bellhousings are almost the same between the two except the starter and clutch release are on opposite sides.

It's possible that the 4JB1 would bolt up to the 4ZE1 transmission, but you'd have problems with the starter (as it would want to go right where the turbo and exhaust are on the diesel) and probably the clutch lever as well.

All right, I may have some excellent news. Recall how I had posted earlier that the 4JB1-T would NOT bolt right in? It appears, for now, that I was incorrect. Sometimes, it feels pretty damn good to have been wrong.

I've just finished bolting the engine into the truck, using the frame brackets and mount pads/isolators (the rubber part) that came with the diesel. This was meant to simply be a test fit, to see how everything lined up and what needed to be modified. Well, the engine went in just like it was from the factory! This should allow enough room for the fan to clear the radiator in the front, and it fits in the bay just fine. The heater hoses and A/C lines even match up!

This mounting will place the rear edge of the block about 2" rearward of where the rear edge of the gas block was located. This, in turn, should move the transmission rearward by the same amount, which means the crossmember mount will have to move back about 2".

Still with me? Good, because here's where it gets interesting. Upon inspection of the crossmember (it was still attached to the old transmission until this afternoon, when I had time to get it torched off - mount bolt was spinning and not backing out), and on JLEMOND's suggestion, there are another set of mount holes I hadn't noticed. Only these are forward of the holes used for the gas engine. Sounds bad, right? Hold on, the crossmember looks like it's symmetrical - there's even a front driveshaft indent on both sides, and holes for the bash guard on the front and rear!

Well, if the crossmember is rotated 180 degrees so that the previously unused holes are now at the rear of the truck, the other holes are about 2" farther back than the gas mount holes (I measured from the most forward outer mount bolt center to the transmission mount hole rough center with the crossmember in both positions, stock and 180 degrees rotated, to come up with this difference. The transmission mount holes themselves are about 3" apart, but since the unused holes are on an asymmetrical outcropping, this seemed the only way to measure. See the photos on my site...). According to my measurements, this thing should bolt right in! The driveshafts will have to be modified, but that should be all.

This is still all a very good guess at this point, but I've been shocked at how well the engine fits and am feeling optimistic. I'll try a test fit of the transmission and crossmember soon and post the results.

I'll be posting detailed photos on my site to illustrate this, as it's rather hard to describe, but it looks very favorable.

As usual, more later ...

Awesome news! Keep those updates coming.

Thanks for the support. Here's the official word:

The 4JB1-T(C) is most assuredly a bolt-in engine. The driveshafts will likely have to be modified, but I've now got the drivetrain all bolted in using the crossmember rotation trick mentioned previously. The transmission was a bit tough to get in, as it needed to be rotated as it was lifted and fitted (much like the C223 trans on the '86 diesels, so I've heard. In fact, I got the idea from this post: Da Wire Thanks, NCDiesel!)

I've added a few things to the site, but there's more to come complete with photos. Stay tuned, in the next day or so I'll get the photographic proof online!

Sorry for the delay in updates. The blog site has been updated to show the final transmission mounting. See it here: blog

I've been working on the fuel system lately, trying to figure out how I'll install the pickup tube and eliminate the fuel pump etc. I've started a new thread with a question about the venting design, which should be near the forum top (as of 8/22/05) so if you've got ideas, toss them there!

Thanks for the interest in the project.

Well into the wiring modifications now. I've removed the dash and HVAC system to ease access and am now trying to determine what's what with the harness. I've made a post in the tech section, if anyone knows anything about the wiring of these vehicles please have a look! Thanks.

wiring thread

Wiring is coming along, thanks to member barak for the diagrams. Once the Helm ETM comes in the mail, I'll be able to make better progress.

I need to order some viton hose to continue with the fuel system, so that's on hold for now, but I think I've got it figured out.

Also added a couple entries to the blog with photos, for those interested.

This is very interesting. What year and model was the donor truck? Is the 4JB1T you used not the same basic motor available in the commercial cabover trucks here in the US? I ask as I'm interested in doing a conversion in a '94(Gen 2) Trooper. I'm eagarly awaiting the results of your conversion...

THE ENG YOU WANT TO BE LOOKING FOR IS THE 4JB1 4JB2, 4JH1 , DON,T EVEN THINK ABOUT THE CAB OVER ENG ANY OF THEM ARE WEIGH TOO HEAVY AND ARE NOT EVEN SIMILAR IN DESIGN THEY ARE HEAVY DUTY DSLS AND THEY WEIGH IN AROUND 6-700 LBS PRETTY BARE, ALSO THEY HAVE AN SAE TYPE OF BELLHOUSING THAT IS CAST IRON, 4BD1 AND 2 AND THE NEW 4HKI AND IT PREDACESORS ARE ALL MUCH TO HEAVY TALL AND LONG TO FIT A TROOPER , AND THEIR RPM RANGE IS ONLY AROUND 2800 TOPS , FANTASTIC VERY DURABLE ENGS AND ARE PROBABLY THE MOST ABUSED ENGS BEING USED IN COMMERCIAL VEH , AND THEY STILL WILL RUN 200K PLUS .. LOOK FOR THE 4J SERIES ENG , THE TROOPERS CAME WITH THAT ENG IN THE REST OF THE WORLD , ANOTHER ENG THAT IS BEING OVERLOOKED, AS THEY ARE KIND OF RARE IS THE OLDER 4FC1, 4FD1, 4FG1, SAME BELL HOUSING PATTERN AS THE 2.3 2.6 GAS ENGS AND THEY WERE AVAILABLE IN 1.8, 2.0, 2.2 AND I BELIEVE THE LAST ONE WAS A 2.4 L ENG BEST PART IS THEY ARE OVERHEAD CAM ENGS , AND THE MTR MT BRACKETS FROM THE GAS 4 CYL WILL BOLT RIGHT ON , EVEN SOME OF THE OIL PANS WILL INTERCHANGE THIS FAMILY OF ENGS, IS THE ORIGINAL STARTING POINT FROM A 1.8 DSL UP THRU THE 2.3 2.6 GAS ENGS, LOTS OF THE DESIGN POINTS ON THIS ENG ARE THE SAME , ENG MTS A, OIL PANS EXHAUST OUTLET POSITION, OILPUMP DESIGN AND THE PISTON COOLERS SAME DESIGN AS THE GAS ENGS
HTH SOME JERRY