AltFuel Suitability of Landcruiser 2H and 12H-t injection pumps for biofuels (1 Viewer)

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Joined
Sep 30, 2005
Threads
8
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449
Location
Perth Western Australia
I have come across a partially dismantled 6 cylinder inline injection pump from a Toyota Landcruiser 12h-t engine from 1988 vintage. It is essentially the same pump as fitted to a 2H Landcruiser. These are a Denso pump.

I have loaded several photos and a 65mb movie file to Injection pump video

The purpose of the inspection, and this posting, is to show how there are no seals internally inside this pump that would cause a problem if running on Biodiesel, nor go brittle with heat if running on high temperature veggie oil.

The side cover is removed from the pump and shows the six springs that control the pump pistons. These are covered in engine oil, not fuel. Fuel is carried in the gallery at the top just under the delivery nozzles and behind the 6 large Phillips head plugs. This gallery might hold 200mls of fuel, probably less.

Tolerances are so small that no fuel escapes past the pump pistons and into engine oil galleries.

There ARE 'O' rings at the base of the fuel supply nozzles, but if they leak it will be obvious on the outside of the pump and not cause any damage - just a bit of a weeping mess and a relatively easy fix after removing injector lines.

You can also see the rubber flange of the boost compensator. Boost pressure is applied to this aneroid and it moves the fuel rack to provide more fuel at boost if the full load screw at the front of the housing is turned OUT.

At the other end of the same shaft of the aneroid, another adjustments controls the fuel supply OFF boost and to increase power at the bottom of your revs and before boost comes on, then screw this screw IN a small amount.

Pictures of this adjustment on an engine are at 12H-T power boost | landcruiser

I've loaded repair manuals at 60 Series Workshop Manuals

I trust this is a useful contribution.

Tim
 
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thanks for the links


love the name of the site too: Doing stuff with a LandCruiser

can't get much more direct than that!
 
2H and biodiesel

Hi Tim I just came across this thread. Are the photos and videos of the 2H pump still available? When I click the link it sends me to iCloud. Regards, Tony
 
Hi Tim I just came across this thread. Are the photos and videos of the 2H pump still available? When I click the link it sends me to iCloud. Regards, Tony

Tony,

I've loaded the video into Dropbox and you should be able to download it from there. Go to my first post and use the edited link.

Some photos are:
12H-T injection pump
DSCF3915.JPG


Aneroid diaphragm - converts the turbo boost air pressure into a mechanical movement.
DSCF3916.JPG



Stopper assembly that sits on top of the governor. Can only be set up with the IP off the vehicle and should not be tampered with.
DSCF3917.JPG


Governor assembly. Plenty of room for looseness to develop in linkages, which create a sense of flat spots under light load.
DSCF3918.JPG


Fuel delivery valves and springs. Driven by camshaft in base of IP.
DSCF3920.JPG


This is what happens when it all goes wrong. This was a brand new piston from a 1HD-T direct injection land cruiser that was powered by veggie oil in a two tank system. The user lent the vehicle out to family who switched to veggie too early, and did not purge effectively. The consequences were catastrophic at 15,000km when the engine failed.
IMG_0379.JPG


These photos show the main seals are copper connections on the banjo bolts. Lubrication of the pump is via engine oil, not fuel.

The delivery pistons are such a tight fit then no fuel will seep past them in any quantity that can contaminate the engine oil, unless the delivery valves are completely worn out, in which case the IP could not produce enough pressure, 3000psi, for the engine to function. ie it's not going to happen.

There is an O Ring, assumed to be rubber, and a gasket of unknown composition , inside the delivery valve. These can be removed from the top of the IP. I've not pulled a pump apart to this point, but from the diagram in the manual, it looks like that if these seals failed they would leak outwards, not allow fuel to contaminate engine oil.

I hope this is useful.

Tim
 
Great photos and videos @Tim-HJ61 .. would be good to see that video uploaded to youtube for long term availability? Do you have an account? or would you mind if I uploaded it?
 
Excellent info. The pic of the damaged piston emphasizes the fact that using VO fuel is only for technically minded people who fully understand how the system works. I suspect that they switched to VO and left it in VO mode continuously. Alt fuels are not for amateurs.
 
Ouch nasty stuff not for the faint hearted.
I'm keen and converting my mid mount tank to a heated coil in stainless or cooper depending on my crash coarse on CVO fuel.
 
John
Thanks after reading about the chicken fat I decided to only run my hj75 on diesel and UVO blends so can you recommended the best diesel uvo ratio.
I don't mind filtering down and d-watering but it sounds like to much work getting the fuel system operating at the right temps for straight veg oil.
Any saving from the pump cost is significant in Australia.
Thanks
:beer:
 
I'm guessing 50/50 would still need heat on cold winter starts so best to run duel tanks with pump diesel and the 50% uvo/diesel mix with the fore mentioned heated pick up.
 
I got one three years from the local Bosch-Denso-Keiki Diesel specialists shop in a plastic bag without part number.
They must be available. ... At least they were here.
My old one was quite stiff and with the same spring preload produced less travel at the rack than the new one. However if I recall it right I compensated this with less spring preload. (as the stiff diaphragm was acting as a spring in itself)
Correctly adjusted, in the end the engine was not running better with the new diaphragm - but good to figure that out anyway.
 

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