Plantoil/diesel conversion basics
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LarsNelson

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Posts: 8
Reply with quote  #1 
Dear Dana,

I have a chance to pick up an 87 F 250 for $500, I read somewhere on
the site that you had a method of converting these to wvo for about
$250 and were willing to share this info.
I also recall you telling me that you had an 84 Ford that you used as
a "test mule".

I have in the past purchased various of your plans.
I currently have 50K on my 1980 Mbz 300 SD using a diy 2 tank system,
so I am not intimidated by the Bosch system, I just have some doubts
about the Ford cav pump setup. Any help, or info, or if you can
direct me to a thread in the mass of info on this or the other site would be very
helpful. I searched the other web site for several days, and havent found what I was looking for.
I live in Santa Barbara Ca. where it rarely freezes.

Sincerely,

Lars Nelson

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Lars Nelson
1980 300SD 25k miles on80/20 WVO/Jet A blend, Fatty injection line heaters
25k more with a DIY two tank system.
danalinscott

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Reply with quote  #2 

Quote:
Originally Posted by LarsNelson
Dear Dana,

I have a chance to pick up an 87 F 250 for $500, I read somewhere on
the site that you had a method of converting these to wvo for about
$250 and were willing to share this info.
I also recall you telling me that you had an 84 Ford that you used as
a "test mule".


I did have an F250 test mule. I believe it was an 87 but would have to find the paperwork to be sure. It was the first year that a 7.3L engine was of erred.

And it may be possible to convert one for $250...depending on you fabrication ability and equipment. It will not be the "best" conversion..but it may be "good enough" for an "old Ford".

Let's see how good a one might be possible on a $250 budget. I am sure you are not the only person who will be interested in such a project.

Quote:
I have in the past purchased various of your plans.
I currently have 50K on my 1980 Mbz 300 SD using a diy 2 tank system,
so I am not intimidated by the Bosch system, I just have some doubts
about the Ford cav pump setup. I live in Santa Barbara Ca. where it rarely freezes.


I ran my Test mule F250 for several MN winters..and loaned it to a farmer who ran it for several more. I think that the CAV pump (shear) problem only appears when someone switches to too thick VO while the engine is at an RPM above idle. I had no problem avoiding this in MN..so I think it should be easily avoidable in "Sunny California".

Let's see how cheaply a two tank conversion of an F250 can be. To do so I think all of the work must be done yourself...so lets try to keep it as simple as possible and avoid such things as welding as much as we can.

First...since a VO tank can be expensive and the F250 already ash 2 tanks..let use one as the VO tank..and the other as the diesel tank.

And lets use the existing 6 port valve if possible as well.

If we use the existing filter for both VO and diesel fuel it may simplify the configuration..but the purge time will be so long such a conversion will probably only be truly suitable for long distance use.  And if/when that single filter clogs...it will have to be changed immediately. Not optimum IMO.

So..it is time for you to make the first choice.

Two filters..or one?
( I suggest two...but it will take at least $50 for a second filter and that is 20% of the budget.)

While you are making that decision lets continue...

If we are going to use one of the existing tanks I think the front one is easiest to work on..and will have to removed to get at the existing 6 port valve anyway.  So unless you have an objection lets use it for the VO tank.

It will have to be drained and removed...so I suggest running it as low as possible on diesel fuel prior to removing it since there is no drain it it. And since it has been on the truck so long I advise giving each of the nuts/bolts you will have to remove a few squirts of WD-40 right now and every few days until you try to loosen them the first time. Air tools will help when you finally do. So will a way to support the tank as you loosen its supports. A strong friend or wood "blocking" (or both) will be helpful at that point.

Once the tank is removed there is a circular port where the  fuel lines enter and the connection for the fuel level sender wiring. Disconnect the wires and then cut the flexible fuel line as closely to the tank inlets as possible. It will have to be replaced with new line anyway as it is probably not very flexible by now. Then carefully remove the port cover. I believe it must be tapped (with a hardwood buffer block and mallet) in a counter clockwise direction to loosen it. But look closely before trying to remove it as my memory from 6 or 7 years ago may not be accurate. 

Once the port cover is loose carefully remove it and the fuel level indicator. You will notice there is a fabric sock on the end of the internal fuel tank outlet. Or should be...they are known to break off fairly often. Tip the tank and drain any remaining diesel fuel into a container. It can be filtered and poured into the rear tank.

Now using a flash light inspect the interior of the tank for any rust or waxy deposits. If there is a lot of rust you should test it with a regular blade screwdriver to see if it is so deeply rusted the tank is likely to leak soon. If you can easily push a screwdriver blade through the rusty area from the outside you will have to find a better tank. If there is a heavy waxy residue on the interior of the tank you need to remove as much of it as possible. There is not an easy way to do this...but a hot pressure washer may help...especially if it has a curved tip . This waxy deposit if not removed will quickly  clog filters for at a thousand miles as it is loosened by warm VO. If you skip cleaning a heavy deposit expect to buy a LOT of in line filters. But maybe you will be lucky and no heavy wax (paraffin actually) deposit will be present.

Next we will need to provide a heated VO fuel pickup for the tank. I used a "HotRod" on my F250...but there is a better option about to be released. I will check to see if the maker is willing to provide one to you for less than a HotRod can be made...but that may take a few days.

So..now you have removed you from tank and the existing 6 port valve should be visible on the frame rail. Squirt some WD-40 on the nuts holding it...and let it sit for a day before trying to remove it. These nuts tend to be rusted so hard they break..and it is good if you an avoid that. Not a major problem if they do..just more work.

That is all the time I have today to help on this project but I will keep my eye open for your decision on the filter. When you make that ..or want more help making that decision..I will continue.







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Dana danalinscott@yahoo.com
LarsNelson

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Posts: 8
Reply with quote  #3 
Dana:

Thanks, this is the kind of detailed info that I was looking for.
I have a spin off filter holder in inventory, so lets say two filters.
I also have several facet type fuel pumps.
Is it necessary to remove the tank to access the transfer valve?
Please tell me more about your hotrod substitute. I have the plan for the hotrod but never used it on the Benz, my sense is that the Ford is a different case.
I look forward to the next chapter in this compelling narrative.

Thanks,
Lars

I mention this in passing:
My 1980 Benz had a tank full of sludge, and probably algae from disuse and storage with 1/2 tank of fuel for over a year. A tank of home brew bio and some marine algaecide seemed to clean it out. When I drained the tank after 100 miles of sloshing around in there the fuel came out an opaque black like a thin crank case oil. I changed the filters, and blew out the lines. No forther problems, done. It had been clogging filters so fast that I didn' know what to do.

Thanks again.



__________________
Lars Nelson
1980 300SD 25k miles on80/20 WVO/Jet A blend, Fatty injection line heaters
25k more with a DIY two tank system.
danalinscott

Moderator
Registered:
Posts: 934
Reply with quote  #4 
Quote:
I have a spin off filter holder in inventory, so lets say two filters.
I also have several facet type fuel pumps.
Is it necessary to remove the tank to access the transfer valve?
Please tell me more about your hotrod substitute. I have the plan for the hotrod but never used it on the Benz, my sense is that the Ford is a different case.


Make certain the spin off filter holder you have will accept a fuel filter available in the micron rating (10 micron in this case) of your stock filter.

I can't recall for certain if you can remove the existing 6 port valve without removing the front tank. (It has been many years since I last did that) You should be able to see it in the frame rail if you crawl under the truck with a flashlight.  But regardless..you are going to have to remove the tank to put a heated fuel pickup in it anyway.

I have not yet heard back from the fellow who is the "vendor" of the alternative heated fuel pickup.



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Dana danalinscott@yahoo.com
LarsNelson

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Posts: 8
Reply with quote  #5 
Dana:

Filter holder will accept a 10 micron filter of large size that is relatively cheap.
I will start spraying bolts with WD 40 asap.

Lars

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Lars Nelson
1980 300SD 25k miles on80/20 WVO/Jet A blend, Fatty injection line heaters
25k more with a DIY two tank system.
misnomer

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Posts: 3
Reply with quote  #6 
I am just about done with my conversion on my 89 F250.

I didn't move the 6 port valve, I left all the lines connected to it and instead I added a 3 port valve ($40) just before the filter head. I made a bracket and bolted a second filter ($9 at pickNpull) to it and the valve along side the stock filter. Then tied the 3 way valve to the switch on the dash so when I switch tanks it switches filters at the same time. I also moved the part of the return line that comes from the fuel rail from the diesel filter to the oil filter, I wanted to be certain I wouldn't be filling the diesel filter with oil while running on oil, which would defeat my purposes.

After the stock 6 way switch I added a inline filter (120 mesh screen) and a inline 2-4psi electric pump ($20 pickNpull) in the frame. (I didn't even have to drill any holes), Just snip the plastic line and slipped the viton hose over and clamped them on.

I chose to replace the rear tank with a 40 gal tank. It just made more sense to me to be able to carry more fuel for trips which is what this truck is for. $200 for the tank. and I went with a coolant heated fuel pickup. I could have made my own, but I opted to purchase a all stainless steel one for $200. I teed my return line into my supply line. The coolant lines I wrapped with that silver bubble wrap looking pipe wrap ($12 for 25ft) and $5 for 3" wide 20mil tape to secure it every 6 or so inches. I didn't bother wrapping the 6 way switch and left the electric fuel pump exposed. Actually that is where I left off, I haven't warpped the coolant line with the supply line once it leaves the frame and across the cross member or up to the filter. I tested it the other day and after the engine was up to temp I switched over and never felt any difference in the engine. After a few minutes I got my IR temp meter and read the temp at the filter and it was up to 130F, without any insulation around it or any heat to it. I was thinking I would wrap the coolant line around it as added insurance but I don't know that it will be necessary. I was also considering placing some of the pipe wrap over the top of the fuel rails to contain the heat for when it leaves the IP to the injectors. Is this a good idea?

See any flaws I need to address? I know I will get a little oil in my filter when I switch back to diesel from the fuel line after the 6 way to the 3 way. At one point I was planning to install the 3way immediately after the electric pump on the frame. Then run a second supply line up to the engine. But I wanted keep the mechanical pump on the engine for the oil supply and I started to think that while I was on diesel, it would create vacuum pressure while it tried to pump but nothing was there.. and thought I might create problems because of that. but it is only 4psi it probably wouldn't have mattered.

I also bought 6ft of viton hose $12/ft. And a handful of fitttings.. tee and hose barbs. ~$20


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1989 F250 7.3L 4x4 super cab, rear tank wvo w/heated fuel pickup.
danalinscott

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Reply with quote  #7 

Won't that make for very long purge times since when you switch tanks you need to wait until the diesel fuel has reached the VO filter before switching to the diesel filter. Won't there be a long "slug" of VO in the line between the 6 port valve and the three port valve when you switch fuels?


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Dana danalinscott@yahoo.com
misnomer

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Posts: 3
Reply with quote  #8 
Dana, yes, I think that slug of oil is going to mean I should wait a couple minutes before shutting down. (But I should let the tubo cool down too before shutting down too, I was considering getting one of those turbo shut down kits that lets your truck idle a couple minutes after you take the key out.)

Originally I was going to place the 3 way valve immediately after the 6 way (about a 2-3" slug), and add a separate supply line for the diesel. But I started worrying about the fuel pump not having any fuel to pump, and moved it. Now I wonder if it was worth worrying about?

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1989 F250 7.3L 4x4 super cab, rear tank wvo w/heated fuel pickup.
danalinscott

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Reply with quote  #9 
Quote:
I think that slug of oil is going to mean I should wait a couple minutes before shutting down.


I think purge is going to be a bit more than a few minutes with that much line to purge. But you can determine that pretty easily.




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Dana danalinscott@yahoo.com
misnomer

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Reply with quote  #10 

If I leave the mechanical pump inline with the oil tank and when I am on diesel it's supply is shut off, will it cause any problems?


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1989 F250 7.3L 4x4 super cab, rear tank wvo w/heated fuel pickup.
danalinscott

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Reply with quote  #11 
Probably.
Most solenoid valves are not designed to withstand much vacuum. I suspect they will not be able to prevent some VO from continuing to be pulled from the tank.

Quote:
Originally Posted by misnomer

If I leave the mechanical pump inline with the oil tank and when I am on diesel it's supply is shut off, will it cause any problems?


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Dana danalinscott@yahoo.com
Taylor

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Posts: 7
Reply with quote  #12 
Dana what conversions on your f250 did you do? Was it just a heated fuel pickup on your truck?

"misnomer" do you just have a coolant heated fuel pickup?

Quote:
I think purge is going to be a bit more than a few minutes with that much line to purge. But you can determine that pretty easily.

 
How can you test this time easily?

thanks
danalinscott

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Posts: 934
Reply with quote  #13 
My F250 (Bessie) was a test mule for a lot of different components and conversion configurations. But the minimum components it ever had was a heated fuel pickup, insulated HOH lines, a coolant/fuel heat exchanger, and a high temp heated filter.

The easiest way to test purge time is to color the VO with a bit of fuel dye and then add a clear hose on the return line just past the injectors. Then  switch to purge mode at idle and time how long it takes for the undyed fuel to appear in the line. This is the maximum time purge should take.  To see what it is a road speed use the same procedure but pull over to check the line.

Quote:
Originally Posted by Taylor
Dana what conversions on your f250 did you do? Was it just a heated fuel pickup on your truck?

"misnomer" do you just have a coolant heated fuel pickup?

Quote:
I think purge is going to be a bit more than a few minutes with that much line to purge. But you can determine that pretty easily.

 
How can you test this time easily?

thanks


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Dana danalinscott@yahoo.com
Taylor

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Posts: 7
Reply with quote  #14 
If diesel passes through a heated filter, raising the diesel temp, will hot diesel cause problems?

Thanks

Taylor
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