Thread: does anyone have any info on injector pumps for 4BD1

Originally Posted by Blknight.aus

nope you can adjust them right the way up till they burst the union fitting if you want to..

higher injection pressure generally equals a better atomisation which means a cleaner burn...

Do you need to pack them with shims or is there something in there to adjust?

Originally Posted by Larns

Looked at my maunal at work this morning, the figures it gives for adjustments to both types of injectors were the same 2630PSI, unsure what that is in kg/cm2.

2630 psi = 185 kg.cm-2

I wouldn't bother adjusting the injector pressures, since the T models stayed the same.

Originally Posted by Dougal

Do you need to pack them with shims or is there something in there to adjust?

Originally Posted by isuzurover

...according to my info on Nozzles - ALL T's had an opening pressure of 185 kg/cm2. NA models had injectors with the same opening pressure until '86/'87, when it changed to 220 kg/cm2. Maybe for emissions reasons??? At the same time, the pressure adjustment changed from screw-adjusted to shim-adjusted.

As above - if you have anything other than a late model NA engine, it should have screw-adjusted nozzles.

With regard to having a diesel camshaft ground to a different profile, be very careful of valve to piston clearance at TDC.

This is one reason small diesels (automotive types) don't have a very large valve overlap/duration. Some extend the duration by having a cam profile that opens the valve earlier then move it toward the closed position at tdc. I don't know if this is common knowledge at shops that grind camshafts.

Originally Posted by isuzurover

2630 psi = 185 kg.cm-2

I wouldn't bother adjusting the injector pressures, since the T models stayed the same.
As above - if you have anything other than a late model NA engine, it should have screw-adjusted nozzles.

If you were wanting to turbo a 1990 4BD1 is it worth changing the injectors over to the earlier type screw adjusted nozzles.

Over flow valve opening pressure is lower (18 psi vs 23 psi) is lower for the 4BD1-T.
Is it worth lowering the opening valve pressure on my motor , by the way I am putting a VGT turbo Garrett (2256V?) and if so what do I require to do it.

Garry

Originally Posted by garryseries3

If you were wanting to turbo a 1990 4BD1 is it worth changing the injectors over to the earlier type screw adjusted nozzles.

Over flow valve opening pressure is lower (18 psi vs 23 psi) is lower for the 4BD1-T.
Is it worth lowering the opening valve pressure on my motor , by the way I am putting a VGT turbo Garrett (2256V?) and if so what do I require to do it.

Garry

I know on a 300Tdi the GT2256V turbo can give about 22 psi boost. I would be interested in hearing how this turbo performs on a 4BD1. It should perform well in the lower rev range where you probably spend most time.

Given a choice, I would like a larger compressor impeller than 56mm for better performance from the higher range of a 4BD1T.

You will probably want an exhaust manifold from a 4BD1T or 4BD2T and an adaptor T2 to what is on your turbo - some info on the manifold in Isuzurover's thread from when he turbo'd his 4BD1.

With turbo upgrades, the air density in the cylinder is greater when the fuel is injected, so higher injection pressure can help the spray pattern. The screw adjustment does make pressure adjustment easier than changing shims, but I doubt there would be a cost benefit when the cost of new injector bodies is factored in.

I'm sure you know to increase fuel rate for more power and watch the EGT.

Edit, also needed are oil pressure and drain lines. From memory there would be info in the above mentioned thread from Isuzurover.

Originally Posted by Bush65

The screw adjustment does make pressure adjustment easier than changing shims, but I doubt there would be a cost benefit when the cost of new injector bodies is factored in.

But if you have two engines it might be worth getting the pressures reset on the old type and swapping them over?

Btw - here is a link to the thread John mentioned:
http://www.aulro.com/afvb/isuzu-land...o-install.html

Originally Posted by Bush65

I know on a 300Tdi the GT2256V turbo can give about 22 psi boost. I would be interested in hearing how this turbo performs on a 4BD1. It should perform well in the lower rev range where you probably spend most time.

Given a choice, I would like a larger compressor impeller than 56mm for better performance from the higher range of a 4BD1T.

You will probably want an exhaust manifold from a 4BD1T or 4BD2T and an adaptor T2 to what is on your turbo - some info on the manifold in Isuzurover's thread from when he turbo'd his 4BD1.

With turbo upgrades, the air density in the cylinder is greater when the fuel is injected, so higher injection pressure can help the spray pattern. The screw adjustment does make pressure adjustment easier than changing shims, but I doubt there would be a cost benefit when the cost of new injector bodies is factored in.

I'm sure you know to increase fuel rate for more power and watch the EGT.

Edit, also needed are oil pressure and drain lines. From memory there would be info in the above mentioned thread from Isuzurover.

Yes Isuzurover thread is a great read as is Rijidig's thread, have made up the adaptor to a ex army turbo manifold here is a pic from my thread.[IMG][/IMG]

The turbo has come from BMW 3.0L diesel engine,I have angled it to point behind the hump so as to allow a bit more clearance.
regards Garry

[QUOTE=Larns;800867]If you intend on working it hard then get the original turbo motor. There is just no substitute for Isuzu engineers.
Turboing a non-t engine is ok, it's what I have done, but you miss out on the benifits of the turbo tuned pump and the turbo ground camshaft, along with the t-model injectors they all add up to getting the most out of this engine. The turbo will suck the usable torque from the low end, I have changed my pump and injectors over and that made a huge differance, and I'm currently waiting for my custom grind cam to be ground. From driving the original turbod engines a fair bit I can't wait to feel the differance that the new cam will make.

Larns did you get a standard cam grind for the turbo motor if not what specs is it and what application was it intended for.
regards
Garry