Thread: 4BD1T Swap from Isuzu NPR

Originally Posted by Tins

Not going to groan at the thread archeology, as I will now read it. Very interested in the gear linkage set up, as I need to do something similar for my OKA. I will, however, groan at the anecdote. Pretty typical of my ARA days.... Reminds me of another, not Army. Bloke was seen driving a van bodied truck. He frequently stopped, got out and beat the bejeezus out of the side of the truck. So of course people had to ask why. He said " this is a ten ton truck and I have a load of twenty tons of budgies, and I have to keep half of the bastards flying somehow.". Groan.

Back to the topic....

Let me know if you're ever interested in the linkage CAD. I think Mythbusters looked at the budgies/pigeons in a truck on a weigh bridge myth - can't remember the result for sure, but I think it was a bust.

Originally Posted by workingonit

You're 15 times our population...sorry, porous border, 16 times...sorry, 17 times...darn it, 18 times...ok, you just have a much larger population than we have.

I chuckled pretty good at this. Sometimes you have to laugh so you don't cry...

Setting aside our ridiculous border crisis, this is a lot of good info. I've read through Sheldon's thread on his MSA to LT230 adapter but hadn't read the thread you linked, so I'll go through that as well. Who knows, maybe I can get something designed here and get the 4BD1 platform more traction in the USA, they're plentiful here in the NPR trucks so I think they're a great option for those who appreciate a mechanical, reliable diesel.

Any feedback on if a stock recored copper 200TDI radiator would be sufficient for a 4BD1T? It would be nice to be able to use what I already have with the radiator and the double core intercooler I currently have installed.

the radiator will be sufficient so long as you keep adequate airflow through it and dont try to over work the engine.

if you want to do some back of the napkin math to check it for yourself.

look at the power output, specific fuel consumption of each engine under typical loadings, the tdi300 (basically the same radiator) and 4bd1-t are very close in the fuel usage for a given amount of work and have very similar thermal effeciencies, the differences come in the delivery of power.

the tdi delivers about the same number of ponies as the suzi but the suzi delivers down low whereas the tdi is a high speed diesel and delivers higher up in the RPM range. You might run into issues if you're working the bottom end at full load and low speed as you wont have the airflow to shift the heat but as someone whose running thermos in a 6x6 in an australian summer you've just got to be not scared of 115-120 degrees in the cooling system and remember to let it cool down before you shut down.

Case in point, driving from melbourne to perth across the nullabor for an xmas break at GCM in a 6x6 with a tandem trailer on the back, my thermo fans turned on exactly never, BUT, my radiator while slightly narrower than the stock unit to make way for the intercooler pipes is a little thicker but has the wide spaced fins and cores to help prevent dust build up in the radiator. The intercooler is fairly close to being the same size as the radiator.

for what you are doing, I would suggest that the stock direct drive fan is going to shift more than enough air through the radiator (assuming decent shrouding) however as you're going to be running in a much lighter vehicle than the 4bd1-t is capable of hauling thermo fans (makes the install easier) or a VC coupled fan (reduces engine load but still gives all the pull of a direct fan when hot) will save you a significant portion of noise and fuel consumption. Switching my 6x6 to thermos pretty much immediately saved me 1l/100 but with the requirement to ensure a cool down cycle before shut down if I'd been working the engine hard in low gears at low speed to allow the block to cool.

Originally Posted by workingonit

Let me know if you're ever interested in the linkage CAD.

Thanks. Not sure if it would help, but it just might. The linkages on the early OKAs were awful. They went cable on later ones, but they changed so much else it ain't plug and play.

Have you got room to move the TC back a bit? For my recent build in a series Forward Control, I used a 4JH1-TC motor and MYY5T main box. I remote mounted a LT230 TC box behind, with a Rakeway flanged input shaft in to the TC. There is a frame between the gearbox & TC to keep things rigid. I can get some photos later today if wanted.

I run a std front drive shaft in the rear (to give an idea of much longer everything gets).

One issue I had is the front driveshaft clashing with the bellhousing. I ended up running a short driveshaft with carrier bearing & uni to "bend" around the bellhousing.

[QUOTE=Tins;3218957]Thanks. Not sure if it would help, but it just might.{/QUOTE]

See what I can do in the next day or two.

I'm on ADSL (not broadband). Don't know the file size off the top of my head.

Wonder if I can post it somewhere on AULRO so others can pick at it. I believe STL format is the go, but will check or others can advise - although if you downloaded FreeCAD you could have the native file and a new experience.

Failing everything else I can post you a USB stick.

Got to consider that when I built mine it was more a case of can I even build it let alone build it perfectly?! - expected one day I would have to revisit and refine. I was happy when I found I could change gears with no problem. I did not have the transmission tunnel cover in place to judge the fit properly (still don't), so some aspects of design might need to be changed. And I think from memory that there was a ratio between the long and the short links, maybe two to one lengths or close to - must re-acquaint myself with that - wrong ratio meant harder to move the lever?

The satisfaction I got, of getting the gear stick to sit straight up in neutral, when return spring tensions were properly adjusted, would be for others akin to using viagra.

As already alluded to, the slip mechanism at the base of the gear stick is what I'm pleased with - went from design to implementation with few issues.

Guess another question is your access to machining or your skills at weld fabricating etc. One offs are so time consuming.

Can't see any reason a STL file couldn't be posted on here, say in TGO or somewhere. My son is a fitter ( def not heredity ) with a lathe and a bloody good MIG I gave him. Well, went halves eventually.

And I have no issues downloading FreeCad.