OK, on to the latest conversion.(#4)

The candidate:
-1994 Dodge Ram 5.9 12V Cummins diesel
-Friend's truck

Considerations:
-Cold climate
-Lots of driving, much in-town
-Owner is very technically inclined


What we have so far:

-Heated tank Custom made, with basically a coolant "jacket" welded to the bottom. No chance of cross-contamination. Tank mounted underneath the truck bed.
-HoH goes from the tank to the firewall
-Heat exchanger something he picked up. Haven't even seen it yet but we'll see if it's effective. Will plumb parallel to heater.
-Pollack 6 port on the way. Getting a bit weary with reports of failures, but mine has worked for 3+ years.

What we are still trying to figure out:

-Electric Veggie pump Brand? Model? Experienced folks please chime in. I've read the threads and searched, no-one has said "I use XXX brand, model xxxx".

-Fuel Plumbing (see attached diagram)
Option A
So far, what I've read most about is Electric lift pump on veggie, mech lift pump on diesel... both going to fuel valve. Return sent back to appropriate tank, or looped on veggie. That's what we're planning at this point(hence the parts list above)
Option B
Use the mechanical fuel pump for both diesel & veggie. At least one person has done it this way.

What are your thoughts? I am very open to suggestions and criticisms... especially coming from people who have run one of these trucks. From what I have read, they are a great truck to run on SVO.


PS. It has a great big honkin Holset turbo & intercooler that almost made me pee my pants. My VW's turbo looks like a poodle hairdryer in comparison.

Cummins_plumbing.JPG (59 Kb, 37 downloads) cummins plumbing

I have a 1995 but I am not in cold weather. My pollack 6 port failled on me. After a long trip. It worked fine for almost a year that had a few long trips. But it did die. I used the same pollack 6 port in three different cars for more than 50,000 miles and it never failed in my Mercedes and 2 VW's.

I now have two 3 ports and I use the stock mechanical lift pump. The diesel returns to the diesel tank and the veggie returns to the veggie-in side of the 3 port(looped).
If you are going to not use the mechanical lift pump I think you should just get two electrics and put one for diesel and one for veggie. The only one pumping will be the one that is being used. I would not loop both the diesel and the veggie and use one 3 port. It creates an air issue. With two 3 ports there are no issues with air that cannot be fixed easily from inside the truck. I would not purchase lift pumps and 3 port valves that is just a waste of money.
My custom made tank has a U shaped tube of aluminum mounted inside the tank and welded to the sides with threaded attachment points this works excellent for me.
You should probably insulate your HOH it is cheap and easy to do and I am sure you have the space for it. While you are at it put some on the tank also, it can not hurt.
Yes mine runs excellent on grease. It is a very impressive truck. I have 260,000 miles and change the oil every 3000 miles without adding any in between. I put 1200 to 2000 miles a month mostly 10 to 20 miles at a time with some trips added in every now and then. I drive mine to the end of the block then switch to grease drive 10ish miles to work and then plug in the block heater to an outside outlet and drive home 8 hours later still in grease mode. It is nice not having to flush at work. Nobody seems to mind. I watched the boss step over my electric cord. The temp gauge before the IP usually reads 135 degree at the end of work. Nice!

Thanks maddasher,

The idea of two electric fuel pumps instead of a swtiching valve is intersting. What would I do with the stock mech lift pump? Just loop the input & output?

Any thoughts as to a suitable fuel pump?

[QUOTE]Originally posted by jake palmer:
Thanks maddasher,

The idea of two electric fuel pumps instead of a swtiching valve is intersting. What would I do with the stock mech lift pump? Just loop the input & output?QUOTE]

Yes..or remove it and install a cover plate on the opening.

Would it be reasonable to assume that an electric fuel pump used in Chev 6.2/6.5 conversions would be sufficent to supply a Cummins 5.9? I'm thinking Holley Blue, would that be overkill?

So what do we use for a fuel pump?

Holley Blue?
Looks like about $110 at Summit Racing... not too bad. Comes with a regulator too. Is that what all you cool cats are using?

Doesn't Craig / dieselrover run a Dodge Cummins? Craig, where are youze?!? What fuel pump are you using?

Hi Jake, my '97 Dodge uses the stock lift pump, and they're fine.

Craig

quote:

Originally posted by Dieselrover:
Hi Jake, my '97 Dodge uses the stock lift pump, and they're fine.

Craig

Thanks Craig!
You think it's OK even in a colder climate? He's being very careful about heat & insulation, so it's not like it will be sucking hydrogenated oil up a 1/4" pipe.

So we would still have to replump the diesel filter to go BEFORE the fuel pump.

By the way... I've edited the original post, the Truck is a 92... not a 94 as I originally stated. Does that change anything?

Thanks again!

I have been running cold blends through a 92 Dodge Cummins for several years in a colder location. The stock diaphragm lift pump has survived all the wierd cold blends that I have fed it.

This link has the info of my testing and vehicle updates.

Wow, thanks guys. Can't get much more of an endorsement than that. Stock lift pump it is!

I've attached an updated schematic for the conversion. It's just the fuel plumbing... so doesn't sheo the heat exchanger, wiring etc. Any revisions peopel can suggest?

Thanks for all the help to everyone who has posted. The guy who owns the truck has helped me a lot over the years, it's great to be able to repay him a bit.

dodge2.JPG (37 Kb, 34 downloads) cummins revised

Jake,
Just belatedly adding to your knowledge. I have tried using electric vane pumps, a Holley Blue and a Chinese copy, with vegetable oil fuels, in blends and straight. I have not been able to rely on them to deliver fuel at the rated pressure, even at idle. The viscosity of oil is just too high I believe (even in 50% blends). I suspect that the pump is slowed by the viscous oil and so the vanes are not able to develop the seal needed to obtain the fuel pressure.
I have swapped the Holley to the start tank and use the stock fuel pump for veggie oil in my '84 300D. In the '81 300D, I have 2, 6 port pollaks set up to switch the fuel source, fuel pump and individual filters to the IP and the return line to the appropriate fuel tank.

Tony, you mention that the fuel pumps have difficulty delivering the viscous fuel. DO you find this is true even when the oil is heated to 130-150*?

It looks like we're going to use the stock lift pump, but your experience with electric pumps interests me. I have often thought about adding a "looped" SVO circuit from the tank... kind of like a "booster" pump so the lift pump doesn't have to draw the fuel all the way from the tank. I've even thought about doing this in Jettas, Mercedes, etc... The other advantage is it would allow you to circulate the oil and get it fully up to temperature before switching over. You could even "preheat" the oil electrically behore you even start the car. I'll attach a schematic showing what i was considering for the vw

Jake,
Yes, it still was not 100% on the heated oil or blends. That is why, in my latest conversion, I used 2 Pollak 6 port valves to select fuel, fuel filter to the IP inlet and the return to the appropriate tank. The Injector return line is connected to the diesel return at the diesel filter. Because the fuel selection is after the stock filter, the top banjo does not need to be a solid bolt.

Gotcha.

We may end up going with a setup similar to what is attached, except the 6 port would be feeding the Mech lift pump instead of the IP. This would allow him to pre-heat the oil and circulate it before even starting the vehicle.

However, we will probably start with what was posted above... using just the stock mech lift pump and no electric pump for vegoil.

vw_with_preheat.JPG (41 Kb, 23 downloads) vw with booster & preheat

Jake,
If you use the setup in the diagram, I suggest that you put the 110V heater after the Heat Exchanger, so that when the engine is started, the cold coolant doesn't chill off the vegoil which is being heated with 110V.
A heat exchanger works both ways. Heat flows from hot to cold, regardless of what is intended.

The fuel selector can not be after the stock filter if the injector return line is going into the diesel filter. Because the minute veggie is in the injectors the excess is going into the diesel filter and then going into the diesel tank. You would have to have a switch in-between the injector return and the diesel filter.

I do not understand.

I am actually using the your last diagram in my 1995. It works great. I do not add much heat to my system since I am in florida. Make sure you have heat if you are in cold climate. And again my pollack valve failed. I replaced it with two 3 ports from greasecar. Seems to work good now even after a trip of 400 miles at 85 mph(it was just the flow of traffic).

quote:

Originally posted by maddasher:
The fuel selector can not be after the stock filter if the injector return line is going into the diesel filter. Because the minute veggie is in the injectors the excess is going into the diesel filter and then going into the diesel tank. You would have to have a switch in-between the injector return and the diesel filter.

I do not understand.

Hmmm. Which diagram are you referring to? In all of them, the return goes back to the selector valve. From there, the diesel return goes to the tank, and the veggie return is looped.

Do I need to revise one of the diagrams for clarity? Thanks for your input!

I have found the carter vane pumps to be useless with properly heated VO since the rotor vane holder is coupled to the drive motor with a plastic which can not withstand VO at 160F. The plastic fails, the pump motor spins but the pump does nothing. The Bosch rotary pumps seem to have an issue with having to suck viscous fluid for an extended period so I would definitely supplement the VO side with a pump, likely a gerotor pump like the Mallory.

It becomes a game of robbing Peter to pay Paul. If the VO is heated properly the viscosity is lowered and the pump is happy with the viscosity but not with the temps, if the VO is within acceptable temps then the viscosity is too high and again the pump has difficulty.

I feel this is true of the diaphragm pumps, and van e pumps but the piston pumps seem to do just fine so comparing a Merc 300D to a VW or a Cummins is of little use.

Just need the Gerotor pump driven by a variable speed motor that has some space between it so the 12V driving motor doesn't see any heat from the hot pump.
I've got a TEEL gear pump to play with "someday". My Chrysler gerotor is still working with no filter on the input, but I've only got about 3,000 miles on it.

quote:

It becomes a game of robbing Peter to pay Paul. If the VO is heated properly the viscosity is lowered and the pump is happy with the viscosity but not with the temps, if the VO is within acceptable temps then the viscosity is too high and again the pump has difficulty.

The "trick" is progressivly heating the VO as it is moved toward the Injectors so that the VO temp is within the design limits of the individual components when it reaches them. This of course limits your available VO fuel system configurations.