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ETD66SS

BD-240 LPG Conversion

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I'm having trouble finding parts to rebuild the Zenith 228 ( https://imgur.com/a/yOqwm) on a BD-240 that's in a 1971 UB240 Power Unit.

I know that someday I wanted to convert the Pettibone fork truck to run on LPG.  I figure since I am having so much trouble rebuilding the Zenith carb that was on the machine, which is not the original, I may as well just go with the LPG conversion now, if I'm spending money anyways...

I've been talking to a guy named Jerry at Nash fuel about the kit I would need, but he's not been the most helpful.  I may go off on my own and buy the components I need, and then build up the conversion system myself.  Thing is, I have never done this before, and wanted to see if anyone here has experience with IMPCO LPG components.

The kit would look something like this: https://www.ebay.com/itm/COMPLETE-IMPCO-LPG-PROPANE-CONVERSION-KIT-GM-250-4-1L-FORKLIFT-TRUCK-CHEVROLET/172194771475?epid=718635117&hash=item28179bb213:g:V9IAAOSwn9lXK0wO&vxp=mtr

It would have a carb/mixer, a regulator, and a filter/cutoff, with all the required fittings and hoses.  I have no idea how to plumb a system like this, hoping someone here has...

 

 

 

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I am no real expert in propane and only know enough to be dangerous.

You need a tank, a forklift tank and mount would be great for your application. You can then change it out with a spare or take in to get filled.

For years the high pressure line of the liquid tap if the tank goes to the regulator only and it worked fine. Just shut the tank valve off when not in use.

That vacuum lock is a good idea but so many run without it.

The propane carburetor is sized by the engine size and then an adapter is bought to fit the carb to the intake. Impco is usually used.

A small vacuum line runs from the intake to the regulator. This is the signal that tells the regulator to send LP to the carb.

The big hose off the regulator then goes to the big fitting on the carb. Run some water hoses to heat the regulator.

That is it and it should run. It is dirt simple.

Instead of the propane carb, you can run what they call a spudin. This puts the propane in the air stream aheaded for the carburetor. You see some of these on pickup engines so they can go back to gas,  if they want to. You then need a valve to shut off the gas when on propane. 

Once it is working, you will see how easy it is and how easy it works. Propane is underrated.

The rock crawler truck crews are using propane so the gas don't slosh to one side of the carburetor and the engine dies. Propane will continue to run the engine, upside down. They love it.

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That description is pretty good other than the system you referred to does not use a signal line to the converter/regulator. The propane is regulated by vacuum in the hose between the mixer and converter, usually 1/2" water column to start to draw propane. There is a small vacuum line used to open the fuel lock to allow liquid propane to flow to the converter. In the Midwest you can contact Acme Alternate Fuel Systems in Mankato MN for any questions. They are the ones that worked with Schwans to convert their trucks to propane starting in the late 70s.

 

 

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Point of order, you are right on the signal line. We just fired a 350 Chevy on propane. It started and ran like a million bucks. And there is no hesitation, stumble or issues like that. It is almost magic. The LP never breaks down, or turns to varnish and plugs your carburetor. It is great stuff for occasional use for these reasons.

I heard Schwans is now running propane fuel injection on liquid and not vapor. Of course you are then into the computer again. 

Where is the Schwans LP truck graveyard? That would be the place to go for a vehicle propane setup, real quick.

 

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Schwans started using liquid injection about 2000. After they could no longer get TBI engines on the GMC trucks the vortex manifolds caused many problems caused lots of problems. Instead of having the air/LP mix in the cast iron manifold it was now in the plastic vortex manifolds. If there was a backfire it would blow a large vacuum cap off, often it would break the mixer off the manifold, and sometimes blew the manifold apart. With those problems Schwan's was desperate for a better system.

The story I heard is that the same man that developed the IMPCO system was working with TRW backing to develop the liquid injection system. It was being tested in South America when Schwans bought them out. Bi-Phase Technologies LLC is the company that manufactures the system located in Eagan , MN. If you go to Bi-Phase.com you can find more information along with installation and diagnostic manuals.

I last worked on their trucks in 2009 when GM quit building medium duty trucks. At that time all the used GMC chassis were traded in to the dealer in Marshall Mn. They were then resold throughout the country. I once had a truck stop by my shop to pick up the three used trucks that I had. Along with two others that were already on the trailer, they were all going to a dealer in Salt Lake City. The driver I talked with said all he did was deliver new and used Schwans trucks all around the country.

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