Isuzu 4bd1 T Info

[Nick B]

Just a few question I would like to ask in regaurds to the Isuzu 4bd1 T Engine in Aussie 110's.

Q1 What PSI Boost are they running standard

Q2 Has anyone done any or all of the following to their engine: ported the head, reground the cams, installed bigger valves and springs, Fitted I better flowing Intercooler, 3 or 4 inch Straight through exhuast, Custom manifold and Water cooled turbo, changed the fueling.

I want to but need to know what others have done so far and if the mods have been dynoed?

I currently run a 300tdi and have severly modified it to produce some insane amounts of HP and NM BUT I don't like the fact that it has a timing belt and a few other issues and intead of Replacing that and rebuilding the engine in 50 to 100K KLms from know I was thinking of doing the above mods to the Isuzu but would also need to change the gearbox as they (R380) don't last long without their own oil cooler while resting behind my current engine let alone the 3.9 Isuzu. I like the 3.9D becuase it has gears instead of a timing chain and belt and there is a huge amount of impovement that can be done to the egine without changing its longevity.

Any Opinions would be fantastic whether good or bad.

[mickrangie]

u might get more info from http://www.aulro.com few guys are running that combo

Mick

[def90]

nick b i think they run around 7 psi standard, i am runniing 12 psi but have not had it dynoed. big difference over stock though. i know someone on this board is running 16psi though

[Nick B]

one other question is Has anyone tried to use and mate the gearbox from the isuzu 4 tonne truck to the LT230 transfer case instead of using the week R380?

Also Does anyone know what the Isuzu Gearbox is called so that I can start looking for one

was thinking of doing the above for a better engine/gearbox setup and then maybe running portals without any suspension lift as a reliable extremly strong Tourer/expedition truck.

Any other ideas to make the truck more reliable and usable.

Ps. What rims are guy's running when they chuck the c303's under there fender's or series trucks?

[Maggot4x4]

I think Bush65 is running the 6 speed Isuzu box.

As for rims, see pics.

[def90]

nick b aounds like your building a monster!! is it a defender? what are your plan for it - comps? road drivable?

[Bush65]

There are 5 speed boxes that were fitted to the 4BD1-T.

I used a MXA-6R six speed but had to use a different bell housing to bolt to the 4BD1-T flywheel housing and fit a larger spigot bush to the flywheel.

The bell housing had to be modified slightly to suit the MXA-6R. The outer races of the bearings on the input and lay shafts protrude slightly to locate the bell housing. The bell housing that I used had to have the recess for the lay shaft machined to suit the larger centre distance between the input and lay shaft.

I am not using an LT230 with this box.

[Nick B]

No I am not Building a monster I just want to get rid of the few things that I want to change or don't like about my Fender 110. If that means it becomes something of desire so be it

oh and yes I want it to be road registered so that may mean I have to build drop downs like Daddylonglegs did I will (Inregards to that, did anyone save the posts he did on how to do that and what the measurements were, and any related photo's) Please email me if you cant post it.

Bush65 In regards to your truck What transfer case are you running?

Do you still have the measurements for the mods you made? And any other info that may help would be greatly appreciated.

The reason I like to have engines with a lot of NM not really HP is it means I can tow boats/truck and other things without the engine piking out or kicking the bucket and I love the Makc truck/tractor feeling you get from a Diesel. AND I also don't like getting stcuk and thats what the diffs are for

[Bush65]

I don't know if you will gain much from some of the engine mods that you mentioned. The govenor limits the maximum revs to between 2500 and 3000 rpm, and doubt you would want to rev past that.

With turbo, intercooler and ijection pump tweaks, you will have lots of torque - plenty to destroy rover gearboxes.

I have an Atlas t/case behind the Isuzu engine and gearbox.

I explained the bellhousing mod in the previous post. The bellhousing bolted straight onto the 4BD1-T flywheel housing. The length was correct and except for needing a little machining to fit over the layshaft bearing, it bolted straight up to the gearbox.

I also had to change the clutch plate because of the larger dia input shaft in the 6 speed box.

I made an adaptor for the t/case and used a custom coupling. I have pulled this out and am re-doing it to move the t/case as close as possible to the gearbox (because I have moved the 4BD1-T back behind the front axle to get it lower). This involves resplining the main shaft.

When I ordered the t/case I could not get an input shaft to suit the Isuzu mainshaft, so I got one that would suit resplining the mainshaft (to give me that option).

My gearbox uses cables to select gears. I adapted a cable shifter from a Toyota Corola to suit. A bit of mucking around with brackets but not difficult.

If you can't get a 4BD1 from a 110, you will have to do something to relocate the oil filters clear of the front driveshaft.

Mine (from an Isuzu truck) has a different starter (with gear reduction) to the landies and would foul the chassis rail with the engine in the same location.

The landie version also has a modified sump with a protruberance on the left side. This probably helps on steep inclines.

[Bush65]

With Volvo 303's, the stock rims are 16" dia x 7-1/2" wide (across tyre beads).

The wheels have 100% backspacing. The large backspacing is required for the correct scrub radius (because the portal box is outboard of the swivel pins). It also protects the portal boxes from the rocks.

Wheel stud pattern is 8 on 8-3/4" pitch diameter.

[Nick B]

thanks mate,

even if the engine has only a little bit more Nm than my 300tdi I would be happy as I don't trust the reliablilty of the tdi or its timing belt. I achieved a heaps of power addition without increasing the revs on the 300tdi and after looking at the head design and how restictive the exhuast/turbo/turbo manifod is on the Isuzu there is a loty of power improvent to be made with just fitting a Decent Cooler/Water cooled turbo/exhuast manifold and exhuast/tuned fuel pump. Most people look at desiel and think they are hard to get more power from but they are that restricted from factory that simple mods can make large differances. EG if I turned the boost up an extra 2psi and and changed the fueling again on the 300tdi I could get an extra 20% But it then starts blowing some black smoke so we have tuned it down a bit.

But at the moment I want strenght and long lasting reliability more than anything. I really appreciate the Help so far mate.

[ISUZUROVER]

Nick, AFAIK the 4BD1T ran about 5psi stock, but lots of people seem to run a lot more without problems.

As a guide, I drove a tweaked 300TDI 110 belonging to a mate of mine (1 turn of the star wheel, relocated boost sensor and increased boost). When I got back into my na 4BD1 powered 110 I thought it pulled a lot harder.

The 300Tdi went a bit better when you wound it right out, and held its speed better up hills, but the 4BD1 pulled much better from idle and felt generally more "driveable".

[Bush65]

Nick, I don't dissagree with your last post. It was things like reground cam from your 1st post that I was thinking might not be productive.

The Isuzu has good torque from near idle, which is one of its good points. It also has a narrow operating rev range and you would not want to run them over 3000 rpm (IMHO), even if you could mod the pump/govenor to rev higher. So if you reduce the low end grunt and can't rev higher, what have you gained.

I have a couple of other projects to finish and I will get back to my bushie. Then I will be looking at changing the turbo on the 4BD1-T and fitting an air to water intercooler, aiming for around 1.5 bar boost.

[Nick B]

in response to the cam regrinding there is usually a far improvment on engines that were designed as long ago as it was. But is say usually as some are perfect the way they are

Just would match it to the external modds if it needs it. The 300tdi didn't need the camshaft changed. But I don't like the 300tdi

Give me an email when you start playing with your 4bd1-t again So we can swap ideas

[ISUZUROVER]

I agree with John, just playing with turbocharging, intercooling and fueling should be more than enough.

The 4BD1T (stock) had variants which produced between 110-140 bhp, all with the same boost pressure and same peak RPM, just with pump/fuelling modifications.

Same as with the NA engine, which had 85bhp and 99bhp variants in trucks and LRs, and probably a few others in gen sets, etc.

All engines had the same cam and had the same flat torque curve.