WVO Conversion Process -- My Request for Advice Page

[Ryan Grimm]

Go ahead and use the slit insulation, although the Rubaflex (rubber) insulation is, IMNSHO better than the poly foam insulation.
Make sure you seal the ENDS of the insulation, because if the air is permitted to flow through the gap between the pipe and insulation it will leak heat.

I go to a local insulation supplier for all my needs. They have a no-return policy, so I'm very careful to order only what I want.
I like them because they have EVERYTHING, or can get it.
Cruise your local Yellow pages if you are near a large enough town/city, or try on-line searches for insulation to get the sheet rubber insulation.

If your sheet metal is clean, consider using contact cement to attach Reflectix to the tank. Reflectix is fairly cheap stuff, and you can use a low-VOC type contact cement that's fairly heat- and water-resistant. And you can layer it, increasing it's efficiency. Being so thin, it'd be easier to apply to narrow spaces. OK, so it's shiny...just tell anyone that asks you're trying to avoid gamma rays penetrating the planet from going through the earth and up your kilt.

One trick to applying stuff with contact cement:
after applying the cement to both pieces, it has to dry for a bit. The problem comes when you try to apply the two surfaces together without it sticking in the wrong place.
My solution is to use wax paper! Put it on one of the surfaces, then slide the other material on. Pull out the wax paper gradually, sticking the sheet material in place as you go. Works pretty well, and it's just a variance on applying Formica countertop material.

[Eric von Kleist]

Originally Posted by lapeer20m

One more thing to consider is what to do with the return line.....

there two options, and I'm not sure which one is best.

option 1: have separate return lines for diesel and veggie that returns the fuel to it's respective tank.

Advantages:
Oil is constantly circulated, thus heating the oil in the tank faster, and filtering the oil several times prior to entering the engine. I would guess from my observations that for every gallon of fuel burned, 9 gallons of fuel is returned to the tank. Oil going towards the tank is always hotter than oil going towards the IP
Air in the fuel line is bled automatically as fuel is returned to the tank. (a lot of air in the fuel line may still require you to bleed an injector)


Disadvantages: higher pressure than stock in the return line can cause injector pump damage.

This is the way I'm going.

option2: Cut the return line, and have it "T" back into the fuel line going in to the injector pump. This seems to be the method used most often in veggie systems i've looked at.

Advantages:
Less fuel line to run

Already ran the extra line...

lower pressure in the return line

I'm guessing you mean pressure like back-pressure in an exhaust system? The distance from original tank's return inlet to the WVO tank's return inlet is only about 6 feet. Would that increase pressure that much? Hmmm...it is about double the distance when you think about it... My return line is 3/8" to the WVO tank, whereas the stock diesel return line is 5/16". That's a 44% increase in cross sectional area. Hopefully that will be enough to offset any increase in pressure due to line length.

supplemental electric (or other heat) raises the temp. of oil higher than the other option since the oil is moving through the tubing about 10 times slower.

I won't have any supplemental heat on the return line, just the heat exchanger in the tank.

no possibility of wvo mixed into diesel

That's the real advantage from my finicky perspective, and it's why I wanted to be able to control the switching valve more directly.

Would it be safe to assume that filters last longer? since far less oil is circulated through the filter?

Hmmm...Seems that once the fuel in the tank is run through the filters once or twice, all the contaminants would be trapped in the filters, and running the (clean) fuel through over and over would not add any additional burden on the filters. Don't know how that will work out.

Disadvantages:
Air in the fuel line is a HUGE headache to get rid of and can plague the engine (and operator) for long periods of time.

No thanks!

Manufacturers always run return lines to the tank leading me to believe that there is a good reason to have a return line

...and I already spent the bread on the line...and the time and effort running it...

I've tried both methods, and had poor luck with cutting the return line. I think that large diameter fuel line should be used for the veggie return line. At least 3/8" ID if not bigger. This will help reduce the pressure on the injector pump.

Again, mine is larger than stock by 44% -- although this was not something I had considered when buying the line: I just took what was available.

One more thing to consider .....
if you use an aux fuel pump, make sure it does not apply more than 5-7 pounds of pressure to the fuel line. High pressure fuel pumps will cause injector pump issues. I know this first hand. After about 1,000 gallons of wvo being forced into the IP @ 50psi, a rubber O ring ruptured inside the Injector Pump causing diesel fuel to drain into the crankcase.

The whole pressure question has been concerning me. I asked about it and where to splice in at the Professional Mechanics forum at http://www.schoolbusfleet.com. The recommendations were helpful. One guy said that the output side of the fuel filters - the line where the fuel finally goes to the injector pump - was probably under 35-40PSI coming from the transfer pump. That bothered me. If I put a TEE in the line just before the injector pump so that I could add the WVO there, I was afraid that the 35-40PSI diesel supply line would overpower the 1.5-4PSI electric WVO pump (32GPH electric fuel pump) that I installed at the WVO tank. I could just see the diesel being pumped BACKWARDS down the WVO supply line! ACK!

Now, I'm going to use the fuel selector valve as the tee. The diesel line from the transfer pump will go to one input valve side of the fuel selector, and the WVO will go to the other. The selector valve is good for 65PSI, so the pump on the engine won't overpower it.

Of course, now that school has started, my incremental progress is going to be glacially slow....

But at least I got the bus unpacked and liveable without having to walk over parts and pieces and tools strewn about the place!

One of the rangers at the park where I work and live came by to visit. He's 6' 5" tall...I have 5' 10 1/2" headroom in the center of the bus... I told him that if he's interested, they DO make taller busses!

[lapeer20m]

seems to me that you have an excellent handle on wvo systems. I'm sure you'll run many many happy miles on realatively free fuel.

[Eric von Kleist]

SCORE!! Woo-hoo!

I just got a source of as much as 50 gallons per week of free veggie oil! SWEET!

One problem...they say it has hydrochloric acid in it!

The oil is from the school cafeteria. They are PAYING someone to haul it off. Apparently when they clean whatever fryers/cookers/whatever they are cooking with, they spray them down with water and some cleaner that has hydrochloric acid in it. The H2O will separate out fairly easily, but I'm not sure what to do about the cleaner. I doubt that they are mixing gallons of the cleaner with the oil. There might be some mixed in, but probably not a huge amount, and the cleaner is probably not straight hydrochloric acid, either, so the total amount in the oil is probably very little.

I could probably just wash the oil with a water and baking soda solution to neutralize the acid. Doing that would also probably help to remove some of the particulate matter, as well.

Hot damn! I got to get the rest of that WVO plumbing hooked up!

[the_experience03]

Most cleaners that contain hydrochloric acid only contain 4% at max. I don't think this would cause you any problems. The way I see it....you ue the stright cleaner on metal parts without any problems so you would think diluted in the oil it would be fine. I think the oil might neutralize some of the acidity too with all the fat in it, but I really don't know. As long as you aren't mixing bleach with the fuel I don't think it should be an issue.

[Eric von Kleist]

I'm going to try to get a sample and take it to someone in the Chemistry department to see what kind of Ph it has, and maybe see if they have any thoughts about cleaning it up some.

It'd be nice if they'd get really interested and pay for a small scale biodiesel conversion project.....

[phillbus914]

I'm becoming more and more interested in a WVO system in my bus. The biggest problem I see (once the system is in place) is finding a good source of WVO. So it would make since to me to have the largest tank possible.

I was under my bus today looking for a spot to mount the biggest tank. It looks like just behind the battery box to the rear tires, along the outside of the frame is the biggest place for a single tank on my bus. I measured that there would be enough room to mount a 2'wide by 98" long tank which looks like it could be about 20" deep. This would give a 203 gallon capacity. At that capacity I could go about 1,600 miles before running out of veggie oil. I think this would be great on a long trip since good veggie oil is usually hard to come by when you’re on the road. I'm not concerned about the weight since 203 gallons of water weighs only 1,687lbs & oil is lighter than water.

I like the idea of using engine coolant to heat the oil, and having a return line plumbed back to the veggie tank. I already have coolant lines that run to the rear of my bus for the rear heater so all I'd have to do is tap into that.

I have a couple of questions about setting this system up.

1. What happens to the diesel fuel when you’re running on veggie oil? Isn’t the diesel fuel pump from the tank pumping it to the injection pump still? Or does it just loop back to the tank through the return line?
2. I read about using the household filters to filter the oil, should you filter before or after heating it?
3. Where is a good place to get a custom tank built? I would imagine this being the biggest cost, single item.
4. What is the approximate MPG loss using WVO vs. Diesel fuel? I would imagine there would be some loss in mileage since there is less energy in WVO than Diesel.
5. What do you do about monitoring WVO level in the tank? Can you run the tank dry and then just switch over to diesel, or would it be a pain to get it running again?

[lapeer20m]

Originally Posted by phillbus914

1. What happens to the diesel fuel when you’re running on veggie oil? Isn’t the diesel fuel pump from the tank pumping it to the injection pump still? Or does it just loop back to the tank through the return line?

Once you switch over to veggie, the valves connecting the diesel fuel to the injector pump keep the diesel isolated from the veggie. The fuel cannot get to the pump (or come from the pump) once the valve is switched over. There will be a small amount of fuel that is in the injector pump when you first switch over, and this small amount will end up back in teh veggie tank, and vice versa. IT's not enough to be concerned with.

Originally Posted by phillbus914

2. I read about using the household filters to filter the oil, should you filter before or after heating it?

Hosehold filters work excellent to filter oil before it goes into the tank. Ideally the oil should be warm. Filters must be changed after about 5-10 gallons of cold (50 degree) wvo, but a filter will last for about 100 gallons with hot oil. You should install a regular diesel fuel filter between yoru veggie tank and the injector pump. This filter should last thousands of miles. They make 12 volt heated filters that are pretty cool, but i don't know if they are really necessary. You can use your stock fuel filter for veggie oil, but the disadvantage is that once it gets plugged, you have to stop and change it....if you have a filter just for veggie, you can switch over and run diesel without stopping for a filter change.

Originally Posted by phillbus914

4. What is the approximate MPG loss using WVO vs. Diesel fuel? I would imagine there would be some loss in mileage since there is less energy in WVO than Diesel.

IF i remember right, my old bus got 8.5 mpg on diesel, and about 8mpg on veggie. It's difficult to tell exactly though, since you're not useing a metered pump to fill yoru veggie tank, you just estimate how many gallons are going in. You'll get more mpg with some veggie oil than you do with others.

Originally Posted by phillbus914

5. What do you do about monitoring WVO level in the tank? Can you run the tank dry and then just switch over to diesel, or would it be a pain to get it running again?

You can buy a universal fuel guage and sending unit online if you look. they were less than $100 bucks...might have even been in the 35 range, i forget. I could see through my tanks, so it make checking the level pretty easy. You could fashion a dipstick rather easily. The guage would be pretty handy to use while driving though. Once you feel the bus start running out of fuel, if you switch over immediately to diesel you'll prob be ok. A cheap 30 dollar low pressure fuel pump from autozone in the diesel fuel line would make priming the system super simple. You'll definately want one of those fuel pumps in the veggie line for sure. Do not have it on all the time, but it makes priming the system so easy.
One note: Most veggie systems i've seen do NOT have a return line. Not having a return line makes priming the engine after running out of fuel nearly impossible. One major function of the return line is to get rid of air in the system. The return line also returns Hot veggie oil to the tank. Fuel in the return line is way hotter than fuel on it's way to the engine. In case your'e not clear, you need a separate return line for the veggie oil. The return line also filters the oil over and over and over again. I would estimate that with a return line, for every gallon of fuel you burn, 10 gallons gets returned to the tank. Perhaps your fuel filter would last much much longer without a return line, since the oil would not constantly be getting filtered, but filtering your oil lots can't be bad for yoru engine.

I don't know if you've read this link or not...but this is an explaination of my first veggie conversion....Is cross linking ok??

http://www.skoolie.net/forum/viewtopic.php?t=223

One more thing...Having a tank that is too big is not so desirable. It takes time to heat the oil before you switch over to veggie. The bigger your veggie tank, the longer you have to run on diesel fuel.

[lapeer20m]

last year on our way home from nevada, the other bus i was traveling with broke down in Elko nevada. That is a great town. I spent a bit of time there.

I think they're smoking crack if they think someone is gonna pay 3K for a bus with a busted IP. Just my opinion.

[phillbus914]

Originally Posted by lapeer20m

Once you switch over to veggie, the valves connecting the diesel fuel to the injector pump keep the diesel isolated from the veggie. The fuel cannot get to the pump (or come from the pump) once the valve is switched over. There will be a small amount of fuel that is in the injector pump when you first switch over, and this small amount will end up back in teh veggie tank, and vice versa. IT's not enough to be concerned with.

Yeah I wouldn’t be concerned with cross contamination either, but what I meant is, isn’t there a lift pump or something that gets the fuel from the tank to the injection pump? With the diesel fuel not being used, what does the pump do?

Originally Posted by lapeer20m

Hosehold filters work excellent to filter oil before it goes into the tank. Ideally the oil should be warm. Filters must be changed after about 5-10 gallons of cold (50 degree) wvo, but a filter will last for about 100 gallons with hot oil. You should install a regular diesel fuel filter between yoru veggie tank and the injector pump. This filter should last thousands of miles. They make 12 volt heated filters that are pretty cool, but i don't know if they are really necessary. You can use your stock fuel filter for veggie oil, but the disadvantage is that once it gets plugged, you have to stop and change it....if you have a filter just for veggie, you can switch over and run diesel without stopping for a filter change.

Ok that’s confusing to me, can you do a rundown of all the filters needed, along with the price. I understand that, the method you use (& I plan to also) filters the oil as its being collected, but how many times and with what kind of filters is it filtered between the tank and engine?

Originally Posted by lapeer20m

You can buy a universal fuel guage and sending unit online if you look. they were less than $100 bucks...might have even been in the 35 range, i forget. I could see through my tanks, so it make checking the level pretty easy. You could fashion a dipstick rather easily. The guage would be pretty handy to use while driving though. Once you feel the bus start running out of fuel, if you switch over immediately to diesel you'll prob be ok. A cheap 30 dollar low pressure fuel pump from autozone in the diesel fuel line would make priming the system super simple. You'll definately want one of those fuel pumps in the veggie line for sure. Do not have it on all the time, but it makes priming the system so easy.

My cheap ass will be using a dipstick or something else that’s nearly free I think. If it runs out, hopefully I can prime the diesel system to get her goin again, I think I can now that I know where the primer ball is on my engine.

Originally Posted by lapeer20m

One note: Most veggie systems i've seen do NOT have a return line. Not having a return line makes priming the engine after running out of fuel nearly impossible. One major function of the return line is to get rid of air in the system. The return line also returns Hot veggie oil to the tank. Fuel in the return line is way hotter than fuel on it's way to the engine. In case your'e not clear, you need a separate return line for the veggie oil.

Yeah I understood that. I like that idea because as you drive the WVO in the tank gets both cleaner and hotter.

Originally Posted by lapeer20m

The return line also filters the oil over and over and over again. I would estimate that with a return line, for every gallon of fuel you burn, 10 gallons gets returned to the tank. Perhaps your fuel filter would last much much longer without a return line, since the oil would not constantly be getting filtered, but filtering your oil lots can't be bad for yoru engine.

I don’t know if it would affect the filter life all that much, I mean once its filtered it’s clean (as far as that filters concerned) filtering it numerous times isn’t going to get it any cleaner therefore shouldn’t shorten the life of the filter. This is probably one of those things you’d just have to try to know what really would happen. Either way if the filters are only a couple bucks, its still better than $3.00/Gallon diesel.

Originally Posted by lapeer20m

One more thing...Having a tank that is too big is not so desirable. It takes time to heat the oil before you switch over to veggie. The bigger your veggie tank, the longer you have to run on diesel fuel.

I thought the coolant to WVO heat exchanger heating method was heat on the fly, meaning ambient temp veggie oil goes in one end and "hot enough" veggie oil came out the other end into the engine. With the return line pumping 10 times more veggie oil back to the tank the tank would gradually get hotter, and the then warm veggie oil going into the heat exchanger would be even hotter.

If thats not the case maybe I'll look into one of those 12volt heater/filter assamblies to mount just before the veggie oil reaches the injection pump.


How hot does the WVO have to be? If it gets as hot as my coolant (190*F) is that good enough? Could it get this hot with just one pass through a coolant to WVO heat exchanger like you have?

I’m really stuck on having a huge tank, because of the difficulty of finding good WVO while on the road. Having a 1600 mile range on a tank of fuel seems appealing to me also. Plus each tank full will save me $586.00 in diesel. I mean think about it, you’d be able to drive from Michigan to Florida or Texas on one tank of FREE fuel. That bus in the above post has 400 gallons of veggie oil tanks! That’s awesome! At 10mpg that’s a 4,000 range on one tank!

Also if I may quote you from an earlier post….

“I had to visit almost 20 restaurants before I was able to find suitable vegetable oil while i was in Traverse City. That was inconvenient, but I didn't bring enough money to drive the 200 miles home on diesel fuel.”

And..

“I took a trip to burnigman and back. At the time, I had plenty of money, but not much time. It takes time to find a suitable fuel source when on the road. I burned maybe 100 gallons of WVO that I brought with me on the trip, the rest of the driving was done on diesel fuel.”

That’s what I would see being one of the biggest headaches once the system is in place aside from a mechanical failure or breakdown and is why I want the biggest tank possible.

[lapeer20m]

Yeah I wouldn’t be concerned with cross contamination either, but what I meant is, isn’t there a lift pump or something that gets the fuel from the tank to the injection pump? With the diesel fuel not being used, what does the pump do?

The lifter pump is attached to the injector pump. The lifter pump would be moving veggie oil or diesel fuel depending what position the valve is in.

Ok that’s confusing to me, can you do a rundown of all the filters needed, along with the price. I understand that, the method you use (& I plan to also) filters the oil as its being collected, but how many times and with what kind of filters is it filtered between the tank and engine?

From grease dumpster to dirty veggie oil tank, only a screen is used on the inlet of my pump.

From dirty veggie tank to clean tank, oil is pumped through 3 water filters, 20, 10, 5 micron (I think...i might have used 20 20 10, can't remember) I use the 20 micron filters to clean the water in the jacuzzi. If it can turn that water from looking like the mississippi river to sparkling clean, i think it's good enough for veggie oil.

From the clean tank, it should go through an electric fuel pump 3-5 psi, then through a regular diesel fuel filter, then off to the engine. Most of the fuel will not be used in the engine, but will be returned to the veggie tank via the return line. This return action will send the wvo through the regular diesel fuel filter over and over again, creating sparkling clean wvo in your tank.


As far as one huge tank.....
How about a large dirty veggie oil tank, and a smaller clean veggie tank? You could fill the large tank ultra fast (15 or 20 gallons per minute) then as that tank gets heated, you can filter oil slowly into the clean tank. Maybe @ 1-5 gpm. You would hate to drive around for an hour on diesel before you switch over to veggie. It woudn't be terrible on a long trip, but that wouldn't benefit you much for around town driving.

That's a very good point you make about me not having large enough veggie oil capacity.

[phillbus914]

I bought the 1st piece of the jigsaw puzzle that will one day become my veggie oil system. A 90 gallon tank. I found it on ebay; it was a custom made fuel tank for a motorhome but was never installed. I measured and it should fit between my frame rails behind the rear axle. I might have to move the rear cross member back a few feet but that doesn’t look too hard to do. Anyway the tank is slanted on one end to allow ground clearance when exiting driveways & such.

Now I have to piece together the rest of the system and somehow put a heater into this tank. My plan is to use this 90 gallon tank as a dirty tank & use a 50 gallon or so tank as a clean tank. This tank even has a small drain plug in the bottom that can be removed to clean it out.

Since I want to get this project going ASAP I may have a temporary clean tank in the back of my bus in the form of a 55 gallon plastic barrel.

Also I found this site about a WVO conversion on a greyhound type bus. He has lots of good illustrations and pictures of his install.

http://bus.getdave.com/Infrastructure/Vegetable-Oil/