Modding my 4jb1t for 250hp

[dieselguy86]

Ok so i spent some considerable time looking at glow plugs. The c223t in the US market came with 5v plugs, the 4jb1 uses 11v. I wanted to keep my working isuzu QOS to keep it as factory as possible. I know that sounds funny since im adding another turbo, but the turbo isnt integrated into the vehicle like the glow plug system. Sensors, fusible links, controllers, etc. i really didnt want to hack up the “system”, so my hunt began.

Downloading the Bosch glow plug product catalog gave me all the measurements i needed:


The m12x1.25 is a somewhat uncommon size, had it been m10x1.25 it would have been much easier.

I couldnt find anything of bosch that was 5v, but a look through denso’s glowpug catalog showed a perfect match, down to the mm and 6v. Denso glowplug DG-241:


The only downside is these arent available in the states, so i had to pay $60usd for 1 plug shipped from uk. I want to make sure everything fits as it should before i spend a whole lot of $$$ on plugs. Ill have to make a new bus bar, but atleast i should have a factory performing system.

-Joe

[geeves]

Where in USA do you live? Chances are that you wont need the glow plugs as that engine will start without a glow down to 0C

[dieselguy86]

Wow, totally different animal than the c223t, that needed a glow below 15°c. Depending on the weather pattern ive seen anywhere from -40°c to +4°c. I live in northern ohio so we can get what we call “polar vortex’s” come out of the arctic. This will be garaged in the winter so I really wont have to worry, but i wouldnt be able to stand knowing i wouldnt have a functioning glow system.

[geeves]

The record low in the city I live in is -3C That took up 5 pages in the newspaper. The airport was closed for a couple of hours trains stopped running etc. People in Nz wouldnt even comprehend -40.

[dieselguy86]

The -40 was a somewhat rare event, and was a whole different type of cold. Alot of peoples cars over-heated because the snow would melt on the radiator, and then freeze. It would keep building up until the entire radiator was froze over. Your nose hairs would freeze everytime you inhaled, it was wild. The normal range is -20 to +4. Believe it or not but my il c223t started in that -40 with a block heater and a freshly restored and operational Quick On System.

[dieselguy86]

Been a bit, time for an update.

The stock exhaust manifold has an ihi turbo bolt pattern. Didnt measure it but i need a garrett t25 bolt pattern. The easiest thing i could think to do was to weld the flange on and machine the manifold out to match. The t25 pattern is alot bigger and will definitely open the manifold up more.

Here the flange is only tack welded into place, and starting the machining. It is a tiny hobby mill and this filled it up. Ive got the bulk of the excess material out of the way now, ill take it to work tomorrow and use a die grinder to remove the rest and blend it all.





Before i forget, the new glowplug arrived and it fit PERFECT. Still stoked about it lol.

Also, ive ordered a couple needle bearings, im going to experiment and see if i can machine the block and cam to accept needle bearings. Obvious advantages are more power freed up, less oil flow needed, and smoother running. If it can be done or not i cant say yet, ill have to have a good chat with my machine shop.
Been doing some research into retro-fitting some roller rockers too, not easy as i thought it would be. Fortunately for me summit racing is 1hr 45min from me, so i might run over there and see if they can help match something up.

[dieselguy86]

Almost 5 months since an update! Work and life kept me out of the garage, but here it is winter time so i have some more time to get back on this project.

Ive scrapped my original turbo idea. Wasnt making me 100% happy. Ive decided to go with an IHI vf38 hybrid turbo for the high pressure turbo, and a Borg Warner EFR 7163 turbo for the low pressure. Im not done with the VF38 so ill leave those details out, but the 7163 is awesome, its the exact turbo used on indy cars, and the math showed it was a perfect fit for this application. Features dual ball bearings, a very lightweight titanium-aluminide exhaust wheel, a forged milled compressor wheel, aluminum water-cooled bearing housing, and stainless steel exhaust housing.



I also received my 12mm pump head today, and will be dropping the pump off at my local fuel injection shop to clean, re-seal, install the new head, and recalibrate the pump.

Hopefully ill get the pistons all ceramic coated within the next couple weeks, then the rotating assembly will be sent out for balancing. After that, itll be ready to assemble. Still need to get some 4jh1 injectors. Anyone have a set? Or can get a set? Hard to find here in the states.

[isuzurob]

4jh1 have a different spray pattern to 4jb1 injectors as the pistons are different so just run 4jb1 injectors

[dieselguy86]

Could you explain a little more what you mean? The 4jh1, 4jb1, and 4jg1 all have relatively the same size/shape bowl in the same spot of the piston. The only thing that could change the pattern would be if the injectos are installed in the heads at a different angle. The size and number of holes may be different too for a cleaner burn, but as long as the installed angle is the same that shouldnt matter.

That being said im definitely open to listening to experience.

[geeves]

I think the 4jj1 is closest to the 4jb1