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My pump has 9.5 mm elements. On a test bench it delivered 180 cc/1000 when the rack was pushed to the stop bt hand (governor removed). With the governor controlling, it could deliver something like 170 - 175 cc/1000 - that is with a modified torque cam.
Do tell, I seem to recall you mentioning that before, but I don't recall the mods in question.
The injection pump on my 4BD1T doesn't have a boost compensator, so when it was calibrated to maximise the fuel delivery rate, the profile of the torque cam was modified, particularly to try and prevent black smoke at low speed when boost pressure was not so high.

The torque cam, in conjunction with the full load stop screw, limit the travel of the control rack - the cam is rotated by a lever that is moved by the flyweights as rpm increases. So the cam profile determines where the control rack stops at different rpm.

The mechanical stop at the end of the rack is only for cold start, when the torque cam is bypassed.
 

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Im pretty sure he was starting with the oil and shutting down with it. When i purchased vehicle it had electric fuel pump that had bypassed mechanical one. When i pulled mechanical pump off it was clogged with a gooey sticky mess that had stopped plunger. Once i cleaned gunk of and put seals through it worked fine.
Would the lubericative qualities be adequate for them injecton pump, and injectors for that matter?
You are probably aware that vegie oil can be to viscous for the engine when cold, hence the reason for starting and stopping on diesel. Also usual to have a heating system for the vegie oil.

Vegie oil provides better lubrication for the injection pump than diesel, particularly with some methods used to reduce the sulphur content in refineries that have the side effect of reducing lubricity (sulphur itself doesn't help lubricity).

Having said that, most (but not all) moving parts in our inline pumps are lubricated by the engine oil.

If the particulates were filtered out and the water was removed (heat, centrifuge maybe) it could.

I have to wonder if the lift pump was clogged how well filtered it could be though. :confused:
Exactly. with waste vegie, it must be filtered before adding to the tank.
 

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Great info and write up Dougal! I checked out the IP on my 4HE1 and it also has a boost compensator but configured a bit differently than the one from the 4BDx series. Maybe I'll get brave and open up the one on my "parts" 4HE1 to compare.
The pump fitted to the 4BD1 (and 2 AFAIK) is a Bosch 'A' type. The 4HE1 has an 'AD' type - slightly different. All 'A' and 'AD' used in Isuzu (edit) automotive applications (end edit) are fitted with Bosch 'RLD' type governors - things like the compensators are listed as accessories in Bosch handbooks, so possibly these have changed over the years.
 

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Discussion Starter #24
An update to this thread.

I've been tinkering with the motion of the compensator to keep the engine clean as it moves through the transition from no boost to full song. At present I am getting a puff of black where the boost compensator hits full stroke before enough boost has been delivered to burn that cleanly.

The issue I have right now is the boost compensator only has ~3.1mm of stroke, in factory form it appears only 0.75mm of stroke is used between on boost and full boost. I appear to be using 2mm of rack travel between on boost and off-boost. The problem being to tune out the puff of smoke requires 1.5mm of preload, which only leaves 1.6mm of travel where I need 2mm.
This is cutting me short on 0.4mm of rack travel, which is a significant amount of fuel and power.

I've got a few ideas to solve this, most involve a stiffer spring, which may be hard to find or stretching the current spring to give more preload internally which won't eat usable stroke the same way that external preload does.
 

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Discussion Starter #25
And another update

The spring behind the diaphragm in the compensator is 33mm long when removed. It is quite soft and results in the boost compensator starting to move around the 3psi mark and being fully open by about 6psi (spring fully compressed). The problem here is black smoke if you are caught in a point where you have more than 6psi boost, but not full boost and you run more power than stock. For me the problem was a puff of smoke I wanted to get rid of during acceleration.

With some pliers I stretched the spring by hand to a new length of 43mm removed. I also stretched the final coil at one end more than the others. This has made the spring somewhat progressive, taking more force to close up the final coil. In combination with the extra preload resulting from the extra length, I now have the compensator starting to move around 4psi and being fully open around 10psi. This is done on the bench with a bike pump and pressure gauge, it's difficult to get an accurate reading.

I have now set the boost compensator up so the unloaded position is resting on the needle (which is modified with a sleeve as in the first post here) and the full stroke of 3mm is available. I have test-driven it, but it's dark so smoke reports will have to wait until later. Boost rise up to 10psi is maybe 1/4 second slower than before so it at least feels like a move in the right direction.

It appears the original 0.75mm stroke on the compensator is fine for stock power and fuel delivery (~70cc/1000 shots).
2mm stroke is used for my current setup, I estimate I'm around 110cc/1000 shots.
Based on that, 3mm stroke should be good for around 140cc/1000 shots or double stock power and torque before requiring further mods.

Further mods if you hit the fuel limit will be similar to a spacer between the cap and can on the boost compensator. There is 4.5mm of stroke hidden in there unused which a longer cap can get.
 

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Discussion Starter #27
Excellent info, thanks.

Do you have any other info on the spring (wire diameter, ID or OD)?
No I didn't, but I will be back in there to measure everything at some point.
Daylight testing shows I still have a slight puff of smoke, I will take it off and adjust by another 0.2mm and see how it goes.
 

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Thanks. :)

There are a couple "hardware stores" around here that cater to the industrial crowd instead of the unwashed masses, thought I would check there as their stuff tends to be a better grade than the Home Despot and Lowest crowd want's to pay for.

Would be kind of nice to be able to find an "off the shelf" part that was close enough to be able to make it work, as stretching a spring makes me nervous (but that's me).

Oh yeah, good to know how the mod is going so far, thanks for that too. :)
 

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Discussion Starter #30
Hey Dougal, would you just use a spacer to get the 4.5mm of space needed in the cover area?
There is a small and light spring inside the spacer, so it's just a tube of those dimensions.

Another update. I pulled the compensator yesterday and added 0.2mm preload in there to add fuel a little slower when it comes on boost. It helped a little, there is no black smoke anymore, just a little grey. But I think I need a spring swap to get it completely clean when accelerating through with my foot up it.
It's a little cleaner right now than the average 1990's factory vehicles.
 

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Excellent info Dougal and well presented,
I will give it a go as I have great fuel starvation problem with the my 4HE1 turbo engine in a boat, Hard to get on the plane until the boost is all in, have No smoke at all. I will make up the sleeve and see if it cures the bog feeling before boost, also want to get the boost in earlier and up a bit as I am only just making 3,000 Rpm at .65 on the boost gauge. Have good water to air inter cooler set up that has helped a little but not as much as expected.
Adjusting the total fuel adjustment on the side of the pump an option do you think...???
I am not that well in the know with injection pumps and don't want to Blow the thing by doing something wrong,
All info greatly appreciated.
Bryon.
 

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Discussion Starter #32
Hi Byron.

First thing with a boost compensator is check the diaphragm in it is air-tight. See if you can blow down the tube or not. If the diaphragm in it has a hole then you're stuck with non turbo levels of power.

Also feel free to remove the needle for a run and see how it reacts. This will give you fuel unrestricted by boost and is great for trouble-shooting.
 

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Excellent info Dougal and well presented,
I will give it a go as I have great fuel starvation problem with the my 4HE1 turbo engine in a boat, Hard to get on the plane until the boost is all in, have No smoke at all. I will make up the sleeve and see if it cures the bog feeling before boost, also want to get the boost in earlier and up a bit as I am only just making 3,000 Rpm at .65 on the boost gauge. Have good water to air inter cooler set up that has helped a little but not as much as expected.
Adjusting the total fuel adjustment on the side of the pump an option do you think...???
I am not that well in the know with injection pumps and don't want to Blow the thing by doing something wrong,
All info greatly appreciated.
Bryon.
Increasing the full load fuel rate via the adjustment on the side of the pump, can help bring boost on earlier. The improvement results from the increase in heat energy/enthalpy (mass flow, pressure and temperature) of the exhaust gasses driving the turbine, necessary to drive the compressor faster if boost pressure is to increase.

Monitoring the exhaust gas temperature pre-turbo, together with the boost pressure, is the best method to avoid over fueling.
 

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Discussion Starter #34
Increasing the full load fuel rate via the adjustment on the side of the pump, can help bring boost on earlier. The improvement results from the increase in heat energy/enthalpy (mass flow, pressure and temperature) of the exhaust gasses driving the turbine, necessary to drive the compressor faster if boost pressure is to increase.

Monitoring the exhaust gas temperature pre-turbo, together with the boost pressure, is the best method to avoid over fueling.
Unfortunately the boost compensator over-rides max fuelling. I turned the screw the wrong way the first time and my maximum speed dropped to about 50km/h. Which took about 30 seconds to reach.

This is one of the reasons I think furthur boost compensator mods might be needed if chasing max performance, it may limit the rack travel before the governor does.
 

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Hi Dougal and bush65,
As always thanks for the valuable information provided here, I was under the impression that the compensator needle was a needle valve as in a petrol carburetor set up. Ok, I too did adjust it in and lost power in one test, I then screwed it out about 1 turn and it provided better power, this was last year. So, I will do as you say and remove it completely after checking for air leaks in this area.
Will this allow for full Boost until the waste gate opens or rev limit via governor or until I pull back on the fuel...???
A Japanese friend also said a turbo that spools a lot faster in the lower RPM range may help a lot....???
I have also noticed a big difference when the engine was in the truck that after I put it in the boat there is a significant higher load on the motor in the lower RPM range in the boat.
So injector pump mods are definitely needed. I have found out recently too that these 4HE1 engines are used in boats here in Japan.
I am of to Biwako tomorrow and will report back with the results.
Thanks all.
 

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Hi, The trip went well, I checked for air leaks.....none. then wound out the compensator adjustment screw fully, and the power screw on the side of the pump 1.5 turns. I now small have a puff of smoke when the throttle is opened up. No black smoke trail at all. The Boost is up to .85 Kg/cm and the RPM is 3,000. Boat is pulling out of the water better but still way off in the top end.
The engine in the truck did pull past 3,600 RPM in top gear. I still feel there is more HP in the motor.
I guess the next steep is to remove the compensator rod completely and have another go....???

Dougal in your opinion would the governor have any influance in this RPM area...???
Regards
Bryon.
 

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Discussion Starter #37
Do you think it's rpm limited or power limited at this point?
The governor will try it's best to hold the rpm the throttle dictates. Follow the throttle cable and you can see if it's hitting the limit screw or not.
 

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Hi, feels power limited or as if it is running out of power at 3,000 rpm. Throttle does hit its limit screw. You only have to move the throttle back from full very little and there is rpm drop off. In neutral will rev past 3,500 rpm easy when momentarily gunned.
 

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I don't have experience with the 4HE1, but 3000 rpm is about what I would expect. I'm guessing that the governor reduces fuel delivery about then to prevent over speeding. Because load and fuel requirement is low in neutral, I think the 3500 rpm would be short time, because the governor can't reduce the fuel significantly from a low rate, but would get control before too long.

If you increased the maximum speed by adjusting the stop screw, you may increase the rpm before de-fueling.

This pic is an exploded parts diagram for the boost compensator used on the 4BD1T


And this for the aneroid (altitude compensator)
 

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Thank's for that, the boost compensator is the same as the one I have, 4HE1 is the last of the Isuzu motors that came out mechanically injected after these they were electronically injected. A Japanese Boatie guy told me the Governor will most likely be the culprit limiting the rpm as the boat is up on the plain and requiring less fuel due to less load.
So now the question is John or Dougal do you have an exploded drawing of the governor area of the pump or is the governor adjustable...?? changing springs or other adjustment...??
Kind regards
Bryon.
 
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