1998 5.9L 12 Valve Cummins Conversion

A description and pics of your SVO WVO Vegetable Oil conversion, help the next person who gets that model.

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1998 5.9L 12 Valve Cummins Conversion

Postby Tmaxxrox97 » Wed May 20, 2015 12:28 pm

Hello all. After a couple months of reading (probably too much...) I have come to the point of installing my system.
I purchased this big blue behemoth with the intention of converting it to save on fuel costs (great for a soon to be college student who will more than likely have to drive a bit for school and work).

I found SunWizards thread found here after browsing the internet in my early searches which lead me here to this forum which I then proceeded to read often. I then came across mike_belbens post found here. Both of these threads were very helpful in the design and install of my system. Thanks to both of you!

I took the information that I found in both of these posts and created my own system based mainly off of SunWizards system just with a minor change.

The change is I am using electric valves from WVODesigns. I did this mainly due to the fact that I would rather flip a switch and let a computer take over than have me forget to turn a valve and end up filling up my diesel tank with WVO.

I had a couple goals when is started this whole project. One was for it to be clean, so no hoses everywhere in the engine compartment. The second was fast switch overs. And the last was a low price tag.

On to the system now I suppose.

First thing I did was get the valves plumbed up and converted to NPT thread. The valves from WVODesigns have ORB (O-ring base) fittings on them which are not the same as NPT but thankfully they are the same as JIC fittings.

My homemade ORB fitting


Once that was all finished it was on to making the HIH tubing that will supply the oil.

For the main supply line from the tank I used 1/2in PEX line mainly for the flexibility. This made it easier to worm it through all the odd turns and bends. The rest of the lines I used the aluminum line and some rubber fuel hose.

This is the line that runs from my heat exchanger to the T in the injection pump line.

Filter in its new home on the frame rail under the driver's door. I bought the filter head and exchanger off of ebay. It is an old VW oil cooler if I remember correctly.

Image Image
HIH installed under the truck. I tried to run them along the same route as the stock fuel lines but I have an extended fuel tank so I had to improvise.

One of my goals when putting this system in was to have the switch over times be as short as I could possibly make them, so I put them as close to the lift pump and injection pump return as I could.

DON'T PUT YOUR VALVES HERE! They look nice and keep lots of room in the engine compartment but as you can see (or not see) they are a pain to get to. I intend on redoing the system in order to move the valves to a more easily accessible location to work on.

Teeing into the supply to the IP.

I tapped into the heater core hose in the same place as normal but I instead ran all of the hoses back down behind the motor to achieve the goal of being clean. I will eventually add some shielding to direct some exhaust heat towards the steel coolant lines for some free heat.

Here is the picture of the dash switch used for the selection of fuel. The switch runs to an Arduino that controls the timing of the valves and will soon control an auxiliary electric heater, and display fuel system information.

This is what takes the Arduino's commands and turns the valves on or off. It has four relays that can control up to ten amps at 220 volts which is way more than my valves require. I bought it off of amazon and had it shipped to my house for around $10, I couldn't make something this clean for that much. (I tried and failed :P )

I had originally planned on going with a small 7-10 gallon tank made from some PVC pipe but then I found this 16 gallon sprayer tank that can be had from northern tool for $40 so I decided I would go with that.

So after all that it's all in. YES.

So far everything works, but does have a couple problems. First, I have a fuel/air leak that I have to track down and fix and of course the little bugs that have to get worked out when you first install a system. Other than those two minor problems everything works pretty well and I've run about 50 or so gallons through.

I will update as time goes on.

Any questions and comments are always welcome!
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