Switching Between Fuel Tanks and Web Sites

[LowGear]

Hi,

I'm going to be converting my diesel truck over to WVO and Diesel or BioDiesel.  I'll need some help with design and strategy.  I'd like you to help me find a good site - like this one - to source such questions as:

Is it proper to run both fuels through the same filters (the truck already uses two factory filters).

Is it proper to heat both fuels? 

Do you recommend heating the WVO prior or after filtering?

Casey

[WStayton]

LowGear;

  I would guess that a lot depends on how filtered your WVO is before it gets to your vehicle.

  If your run it through a centrifuge and then finish it up by running it through a 2 or 3 micron filter, the only thing that you are going to have in the WVO when you put it in your vehicle is, maybe, some high(er) melting point HC's that fall out of solution in the WVO and gum everything up.  For these you would want to use heat in the sytem as soon as you can get it to the WVO, like in the tank!

  From a standpoint of performance through the injectors, most (!) diesel engines will have less problems if you heat the injectors and/or heat the WVO just before it gets to the injectors.

  Take what I say with a grain of salt, since my knowledge is ALL empircal, at this point (haven't burned the first liter/gallon of WVO in anything, YET!  <grin>) and most of the knowledge I have picked up is with respect to Mercedes OM616 and OM617 diesels which seem to be relatively WVO friendly, in that they have an injection pump that isn't real fussy about what is going through it, so long as it is some where near the right viscosity. 

  I have seen picture of Mercedes injector running in free air (i.e. not in an engine) and the differance in spray pattern with 50 degree WVO and 190 degree WVO was VASTLY different.  Nice spray pattern at 190 degreesand lopsided squirts/dribbles with the 50 degree stuff, through the same injector.  So, I believe that, at least in free air, there is a vast differance in spray pattern depending on temperature.

  If, on the other hand, you just filter the WVO through a sock and then dump it in to your vehicle, you need lots of filtering capacity, preferably heated (so that it doesn't get clogged with wax that falls out of the WVO) before the WVO get to the existing vehicle filters!

  As usual, your YMMV!

  The above is worth exactly what you paid for it!

Regards,

Wayne Stayton

[bschwartz]

I have about 40,000 miles or more on WVO.  I have run it in my mercedes (as wayne says, they are very forgiving) and in a'95 GMC Suburban 6.5 (also an IDI motor).

The first and MOST important question, is what is the vehicle?

This is the first forum I would frequent if I were a first timer.
http://biodiesel.infopop.cc/eve/forums

[LowGear]

Aloha bschwartz and Wayne,

Veggie and a couple of other well intentioned members have me building a better than average WVO processing station.  It will be a heated centrifuge tank system.  It won't be quite as cutting edge as theirs but far better than my previous plan.

Unfortunately I have a 1986 Isuzu NPR.  I write "Unfortunately" as NPR only produced IDI engines from about 92 until 97 as I currently recall.  When this 86 gives up I'll pick-up one of the 95 or 96 chassis that have disk brakes and low cut windows.  Back when I was sleeping with a 283 Chevy I would have never guessed I'd end up favoring this dump truck over all my other toys tools of capital production.

I've slopped some 10 micron WVO into Izzy but until I have the finer stuff out of the new processor that will not happen again.  Once I have the <5 micron VO I'll start blending it with diesel at around 40%.  It never gets below 65 in my part of paradise just in case your wondering.

I'll cruse the site mentioned above and look forward to other references.  This last electrical bill came in at 42 cents a KWH.  The Witte will know the taste of WVO and Bio Diesel as well.  Projects Rule!

Keep up the good work.

Casey

[bschwartz]

Casey,

To answer some of your questions more directly.....

Is it proper to run both fuels through the same filters (the truck already uses two factory filters).

   I would use separate filters.  If one clogs, you can use the other fuel source, and purge times are much shorter.

Is it proper to heat both fuels? 

   I do.  I don't know the fuel injection system on your NPR, but on my 6.5, the rotary pump isn't known for being the strongest.  My thinking is that by heating BOTH fuels before the injection pump, when I switch fuel sources, there is no thermal shock as they are both the same temperature (around 185 F).  There is some concern about new low sulfur diesel not being as good a lubricant when heated.  My solution to that problem is to add about 5% WVO to my diesel tank.  The WVO tank remains 100%.

Do you recommend heating the WVO prior or after filtering?

   If you mean the fuel that is in the vehicle, I say YES.  Even my best cleanest oil sometimes gets a little bit of thicker oils/fats that get in the mix.  Although it is all clean and will burn well in the engine, until it is heated, it can potentially be thick enough to clog filters.  If the filters are heated, or the fuel is heated before entering the filter, that problem can be reduced or eliminated completely.


I hope some of this opinion is helpful.

Good luck with the project,
-Brett

[LowGear]

Aloha Brett,

40,000 successful miles tells me just about everything I need to know.  The more I learn about WVO the more I understand about factory diesel.  Its beginning to look like I'll need to know a lot more about the fuel system on the NPR.  The knowledge should transfer to the Witte generator.

A fellow on CL wants $110 for two 3 port solenoid valves.  Good deal?

Casey

[bschwartz]

that being a good price depends on what brand and model the valves are .

[LowGear]

Hi,

This first link is to the valves in Hawaii.  This seller just phoned me back and has converted half a dozen trucks for his employer and the first one was five years ago.  I will be visiting him soon after I return to paradise in July.

http://honolulu.craigslist.org/big/pts/2427379548.html

Another valve I saw on eBay looks real interesting to me as well.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260803223392&viewitem=&sspagename=STRK%3AMEWAX%3AIT

The fellow in Hawaii mentioned they had tried the motor drive valves which resulted in complications but I don't know if they were even the same manufacture much more model.

This link has a pretty down to earth schematic.  You have to page down to view it.

http://www.wvodesigns.com/wiki/Mercedes_Conversion

I found it curious that the diesel line was left to return all the way to the tank while the WVO was back-fed to the heated filter?

The current plan is to strip the tank, gauge sending assembly and filters (three if you include the water separator) from another NPR.  Finding small NPR tanks is difficult so I may have to have a larger tank split into two side by side tanks but still go with second gauge sending assembly and filters. 

Do people ever run a copper fuel line up the exhaust pipe for a few feet to harvest heat for the WVO tank? 

Casey

[bschwartz]

The looped return for WVO is common, although not without it's problems.
The theory is to return already heated fuel to the filter, which helps keep the heat localized.
The only problem I've seen with that setup is if air gets into the line, there is no where for it to go....

The local valves look like they would do the job as long as the ports have a common thread size for screwing in nipples (go ahead and throw your comments in....).

I would not recommend copper lines, as they can react with the WVO causing polymerization issues.  I've had good success with aluminum lines.  I haven't wrapped the aluminum around the exhaust, but I don't see any reason it wouldn't work.

[LowGear]

Air in the lines.  I've seen automatic bleeders in water lines.  Is there such a thing as an auto bleeder for fuel lines?

Copper lines causing problems.  So that's why I see so many fancy lines or brass. 

I was thinking more of putting the (now) aluminum line inside the exhaust pipe on its way up to the engine area.

Casey

[bschwartz]

I've never seen an auto bleeder for fuel lines, as bubbles would usually just pass through to the return to tank line.  I wouldn't recommend putting the aluminum lines IN the exhaust.  I would imagine that corrosion would kill your lines in quick manor.

I would suggest either along side the exhaust, or use a Hose In Hose arrangement with coolant lines.

[Geno]

I've got about 10,000 WVO miles on my 1985 300D. I did a summer only conversion and use the same filter for WVO and diesel. It has manual valves in the trunk with the WVO tank. The WVO is returned to the tank. My 10 plate FPHE gets the oil plenty hot enough for the filter and IP. After an hour the WVO tank gets up to 125°f or so. There is a lot or return fuel on these old MB's. I have heated injector lines as well and they get the fuel up to 160-180°f. The car gives me plenty of warning when it wants a new filter and it's a 10 minute job. Timing the purge is easy with a clear fuel filter on the return line in the trunk. I didn't follow some of the standard rules as Brett has outlined but so far so good. The up side is it's real clean under the hood. Very little plumbing or wiring and no heated filters or valves. Also, when running on diesel the only place WVO sits is in the WVO tank.

http://www.genedevera.com/temp/mb/index.htm

Thanks, Geno

[mike90045]

I've got about 10,000 WVO miles on my 1985 300D. I did a summer only conversion and use the same filter for WVO and diesel. It has manual valves in the trunk with the WVO tank. The WVO is returned to the tank. My 10 plate FPHE gets the oil plenty hot enough for the filter and IP. After an hour the WVO tank gets up to 125°f or so. There is a lot or return fuel on these old MB's. I have heated injector lines as well and they get the fuel up to 160-180°f. The car gives me plenty of warning when it wants a new filter and it's a 10 minute job. Timing the purge is easy with a clear fuel filter on the return line in the trunk. I didn't follow some of the standard rules as Brett has outlined but so far so good. The up side is it's real clean under the hood. Very little plumbing or wiring and no heated filters or valves. Also, when running on diesel the only place WVO sits is in the WVO tank.
  http://www.genedevera.com/temp/mb/index.htm
Thanks, Geno

I'd be a bit concerned about the RUG you mix into the WVO, if your return line heats your WVO tank up that much.  RUG is going to want to vaporize, and go somewhere.  I'm glad you switched to diesel mix.    Nice job on it all.

[bschwartz]

Ahhh, but the RUG would vaporize in the tank pressurizing it.  That would eliminate the need for a fuel pump 

[LowGear]

Keep It Simple Smarty!

I must have been channeling your design when I started twilighting the two tank approach on my truck.  As I've mentioned it never gets below 65 here and 70 is the common early morning temperature so you're system is pretty exciting.  The real downside is I don't have the miraculous Mercedes IDI 80's engine.  And for that reason I'll be reading Brett's contribution many times.

Like heating the WVO as it comes out of the tank so that it is hot (very warm) when it hits the filters.  A complete set of separate filters is a pretty steep curve but pre heating for sure on the WVO line.

Both of you recommend or use an additional pump on or near the WVO tank.  I wonder if one of those in-tank pumps would be a sensible idea.  OK, a plausible idea.  It would save an external mount and provide physical security for the pump.  How about something like in a Toyota RUG powered truck tank?  I use the truck on a farm and drive through bushes once in a while.

I need to call Matt at Universal Welding to see how much splitting a round fuel tank into two sections would be?  200 miles is a road trip for me.

Let's keep those little gray cells cooking.

Casey