Using Stock Mechanical Lift Pump Questions

For discussing the modifications needed for diesel vehicles to run with 2 tank veggie oil conversions.

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Using Stock Mechanical Lift Pump Questions

Postby every1elsesdoinit » Mon May 24, 2010 12:15 am

Hello,
Wanted to start by saying thanks to all of those who are putting so much information out there. I wouldn't even be considering this conversion without all of your help.
I'm looking to convert a B600 School Bus with a 6.6L Ford/New Holland Turbo Diesel Engine. Right now the biggest question I have is whether or not to use the stock lift pump. The bus has a mechanical lift pump and I've read several of SunWizards posts suggesting that this would be enough. I like that it is a cheaper solution, but if it was necessary, I wouldn't scrimp on the cost of a nice electric pump.
I've heard rumors of ruptured diaphragms on mechanical lift pumps (i think because of VO's solvent properties?) which flooded the crankcase with veg-oil. Anyone? Anyone?
Also, my understanding is that on my vehicle, the lift pump sits before the stock filters. So I would want a 3way valve before the lift pump and then after the lift pump as well so that I could have 2 separate fuel filters?
And the other question I have is about looped returns. Someone on a diesel forum suggested that looping the return when using the stock mechanical lift pump might be bad news because you could build up too much pressure. Basically I think he was suggesting that the return would feed into a line that already has fuel in it and build up pressure by not being able to flow freely? I'm not sure I totally follow this--without any real automechanic knowledge it seems like the return rate would be much less than the fuel intake--, but I like the idea of a looped return for heating purposes as well as purge times. Any thoughts about this? Should I just run the line back to the tanks?
Any help would be great. Also any specific knowledge about this vehicle/engine.
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Re: Using Stock Mechanical Lift Pump Questions

Postby SunWizard » Mon May 24, 2010 2:18 pm

Hi and welcome to the forum.
every1elsesdoinit wrote:The bus has a mechanical lift pump and I've read several of SunWizards posts suggesting that this would be enough.

Only on piston lift pumps like cummins and mercedes. Others with diaphragms aren't nearly as good, but they are cheap.
I've heard rumors of ruptured diaphragms on mechanical lift pumps (i think because of VO's solvent properties?) which flooded the crankcase with veg-oil. Anyone? Anyone?

Yes some dia. pumps can do that simply due to age, and maybe from VO, and its a big drawback.
Also, my understanding is that on my vehicle, the lift pump sits before the stock filters. So I would want a 3way valve before the lift pump and then after the lift pump as well so that I could have 2 separate fuel filters?

See my truck diagram here under converted vehicles, it would probably be good for yours.
And the other question I have is about looped returns. Someone on a diesel forum suggested that looping the return when using the stock mechanical lift pump might be bad news because you could build up too much pressure. Basically I think he was suggesting that the return would feed into a line that already has fuel in it and build up pressure by not being able to flow freely?

Untrue. When you loop before the lift pump (see my diagram), you get no added pressure. I am sure "someone on a forum" has done it wrong! (loop after the lift pump.) There is no benefit to a return line back to the tank if you plumb it like mine.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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Postby rkpatt » Mon May 24, 2010 3:34 pm

FWIW on mechanical lift pumps -

Taken from a catalog description for an Airtex / Master brand mechanical pump -

"...Advanced polymer pump diaphragms help ensure consistent performance in multiple fuel blends..."
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Postby every1elsesdoinit » Tue May 25, 2010 11:15 am

Thanks so much for those quick replies. I'm surprised at how quickly you are able to respond to all of the varying questions you get at this and various other forums. I imagine your breakfast being something like coffee, toast and checking all of the new posts on all of the veg-oil forums and posting replies.
Unfortunately, I am away from the bus and the shop manual for the bus (argghhh), so I'm doing as much research online as I can. One more quick question:

If the diaphragm on the lift pump were to fail I would immediately lose power to the engine and very likely flood the crankcase? If I were to flood the crankcase, can this be solved by simply changing the engine oil? Would I have to worry about changing seals, etc? Does it need a more extensive flush?

I think the plan for now will be to get home, check on the shop manual and decide how I want to proceed. I kind of like the idea of running the veg-oil on a separate pump so that I won't be putting any extra stress on the stock system. I don't really like the idea of having a the lift pump break and then just being stuck. Seems much better that if something on the veg-oil system went wrong, I could switch back and keep running. Either way I might need to start looking into towing insurance. Also, I need to find out what kind of pressure the inlet at the IP wants.


Thanks for all your patience and help,
Max
West Coast
1991 Ford B600 Schoolbus
6.6L Turbodiesel running on 2 tank VO
Hotfox pickup, TIH fuel line, coolant wrapped filter, 26 plate FPHE, temp and pressure sensors

You all are lifesavers
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Postby rkpatt » Tue May 25, 2010 11:52 am

Generally that could happen, especially if the pump is mounted on the engine lower than bottom of the fuel tank . You should have a pressure gauge on the inlet of the IP to make sure that it is getting the factory spec minimum pressure at all times with both fuels .

"If the diaphragm on the lift pump were to fail I would immediately lose power to the engine and very likely flood the crankcase? "




If I were to flood the crankcase, can this be solved by simply changing the engine oil? Would I have to worry about changing seals, etc? Does it need a more extensive flush?

If it failed I would think that multiple very short interval oil and filter changes would in order but I wouldn't foresee seal replacement assuming you identified and addressed the problem immediately .


I do not believe that if you start out with a new pump and and replace it every year or two ( preventative maintenance ) that a you would experience a pump diaphragm failure .


The reliable electric WVO pump options are gearotoer pums from FASS , Raptor, and soon a new one to be sold by www.wvodesigns.com .
Last edited by rkpatt on Tue May 25, 2010 12:42 pm, edited 5 times in total.
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Postby SunWizard » Tue May 25, 2010 11:55 am

every1elsesdoinit wrote:If the diaphragm on the lift pump were to fail I would immediately lose power to the engine and very likely flood the crankcase?

I think they fail slowly at first. Whether that is one that can flood the crankcase should be your first thing to study. If its like the Ford truck engines its made by international and that info should be easy to find since they fail on diesel too, just not as quickly.
If I were to flood the crankcase, can this be solved by simply changing the engine oil? Would I have to worry about changing seals, etc? Does it need a more extensive flush?

Depends on how quick you catch it and whether the VO polymerizes. Once that happens major engine damage can happen since the oil turns to jello and is hard to flush and fix.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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Postby every1elsesdoinit » Wed May 26, 2010 4:23 pm

Cool Cool. Thanks for all the help. I suppose I'll have to get back to CO and take a closer look at the bus and the shop manual. Until then....
West Coast
1991 Ford B600 Schoolbus
6.6L Turbodiesel running on 2 tank VO
Hotfox pickup, TIH fuel line, coolant wrapped filter, 26 plate FPHE, temp and pressure sensors

You all are lifesavers
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Joined: Sun May 23, 2010 11:38 pm

Postby every1elsesdoinit » Sat Jun 12, 2010 10:39 am

Ok so I've returned to Colorado and I'm trying to get to work on it, but I'm still feeling stumped about the lift pump. At skoolie.net two users, Lapeer20m and the_experience03 have both done the conversion on the same 6.6 engine. the experience03 posted pictures and a brief description of how he went about converting. We have exactly the same setup under the hood. http://www.skoolie.net/forum/viewtopic.php?f=16&t=2639 is the link to his description. The bus has a main filter/water separator and then 2 secondary filters after. In the experience's set up it looks like both veg oil and diesel flow through all three of these. It looks maybe too easy to be true?
I have the shop manual for the 1991 vehicle, but apparently my bus was actually made in 1990 and has a carry-over engine which is significantly different than the one described in the book. argh. Sunwizard, you told me that i should study whether its possible for this pump to flood the crankcase. Any suggestions on how to find that information? I think there's a diesel shop in longmont--I was thinking of going to them to ask a few questions. I'm a little concerned right now that the lift pump might actually be internal to the injection pump? Its pouring right now so I think i'm going to wait a little to go back out and do some more sleuthing.....
West Coast
1991 Ford B600 Schoolbus
6.6L Turbodiesel running on 2 tank VO
Hotfox pickup, TIH fuel line, coolant wrapped filter, 26 plate FPHE, temp and pressure sensors

You all are lifesavers
every1elsesdoinit
 
Posts: 22
Joined: Sun May 23, 2010 11:38 pm

Postby SunWizard » Sun Jun 13, 2010 11:36 am

every1elsesdoinit wrote:The bus has a main filter/water separator and then 2 secondary filters after. In the experience's set up it looks like both veg oil and diesel flow through all three of these. It looks maybe too easy to be true?

If its a brazilian new holland engine its not like the ford trucks so not many will have experience with it, and you will probably get all kinds of wrong advice. A conversion with shared big filters to purge can take a long time (20-30 minutes) to purge. A seperate filter for VO is the way to go for many reasons, purge is one, and if you plug a filter you can simply switch a valve and then know if that was the problem, and keep driving if its dark, raining, and not a good place to be stopping and changing filters. He gives no diagram so its hard to know what he did in the thread you link.
I have the shop manual for the 1991 vehicle, but apparently my bus was actually made in 1990 and has a carry-over engine which is significantly different than the one described in the book. argh. Sunwizard, you told me that i should study whether its possible for this pump to flood the crankcase. Any suggestions on how to find that information?

Shop manual, or follow the fuel system, find the lift pump and remove it and examine.
I'm a little concerned right now that the lift pump might actually be internal to the injection pump?

Yes it could be, and if thats the case its best to add an electric pump for VO. It sounds like you have a bosch IP which is far better than the stanadyne IP used on ford pickups.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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Postby every1elsesdoinit » Mon Jul 12, 2010 2:16 pm

Ok so its been a pretty long time, but i've been kind of busy and ultimately I figure that its better to do this right than it is to do it quickly. Plus i think I just move really slowly....

So the verdict is that my lift pump is a mechanical piston pump. Its a Bosch 9 440 080 018 and if you're really curious you can see the diagram for it at: http://www.atinet.com.br/manuais-toyota ... diesel.pdf

Which means no worries about rupturing the diaphragm and flooding the crankcase and no need to buy an expensive electric pump and then worry about removing the stock lift pump and sealing off the crankcase. Wooohooo!

I've already installed a hotfox coolant heater/pickup in the hdpe 30 gallon drum and I've received the 26 plate FPHE.

So i think the next decision is veg-oil filter and what kind of valves. Right now my thinking is that I'll just give in and buy a racor 1000H and a set of three electric solenoid valves. The valves would be a pretty long distance from the driver's seat (too far for the long stem mechanical valves i think) and I'd prefer not to have to end up opening up the hood every time i want to switch something (1. switch fuels and return to veg oil, 2. switch fuel to diesel 3. switch return to diesel). The racor would end up being installed right before the lift pump because it wants to operate on vacuum. This will all end up being pretty expensive, but worth it? This would end up being the diagram:

Image


Well I'm going to think on this a bit longer..... Anyone let me know if they have any questions, concerns, comments, etc. I'll probably end up finalizing this and then ordering later this week and I can get this going.
West Coast
1991 Ford B600 Schoolbus
6.6L Turbodiesel running on 2 tank VO
Hotfox pickup, TIH fuel line, coolant wrapped filter, 26 plate FPHE, temp and pressure sensors

You all are lifesavers
every1elsesdoinit
 
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Joined: Sun May 23, 2010 11:38 pm

Postby SunWizard » Mon Jul 12, 2010 4:08 pm

I don't think the racor is worth the large extra cost compared to a cimtek for $19.50, with cheaper and more common replacements.

I also don't like filters and connections under vacuum since it leads to air leaks which is a very common problem.

If you are going with the VO filter under vacuum you might as well put the D2 filter under vacuum (and maybe the FPHE) before the lift pump and you can eliminate 1 valve making things simpler to plumb and operate.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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Postby every1elsesdoinit » Tue Jul 13, 2010 3:26 pm

Ok so you convinced me to route it slightly differently. I thought that I would need an electrically heated filter to clear out any gelled VO that might have accumulated overnight, etc, but if Sun is in Fort Collins (read: cold winters) and wrapping his filter with coolant works for him, then I think it will be fine for me. Plus it will save around $200

Image

I'll just make sure I do a good job wrapping the filter so that it can melt out any gelled VO left in it.
I just ordered all of the parts for the HIH set-up, the filter head and a pressure sensor. I'm still thinking about the valves--three solenoids seem like a lot to buy at $80 a piece, but I have been saving a lot of money on all these other parts and I'm really not sure that I'll want to pull over, get out of the bus, open the hood, and flip some manual switches each time I'm changing over......
Also, I have to figure out how/where I'm going to be cutting into the metal fuel lines. I read that you just put hoses over the metal lines and clamped them down. I'm really glad that works, because I would've spent a long long time trying to figure out how to make those connections probably.
West Coast
1991 Ford B600 Schoolbus
6.6L Turbodiesel running on 2 tank VO
Hotfox pickup, TIH fuel line, coolant wrapped filter, 26 plate FPHE, temp and pressure sensors

You all are lifesavers
every1elsesdoinit
 
Posts: 22
Joined: Sun May 23, 2010 11:38 pm

Postby SunWizard » Tue Jul 13, 2010 9:44 pm

Now your diagram looks just like mine you can see in the converted vehicles section here, see that to add the coolant flow.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
Site Admin
 
Posts: 1723
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

Postby every1elsesdoinit » Fri Jul 30, 2010 1:06 pm

thanks so much for all the help. I've finished plumbing the fuel and coolant lines. I haven't finished wiring the electrical valves yet, but I'm going to need to move the bus soon, so I thought I would make sure i could get it running on the stock tank w/ biodiesel again and then worry about wiring the valves.
I'm having troubles getting it to start...... I've been following the shop manual's instructions for starting it again after running out of fuel: pump the hand primer on the lift pump 70ish times, open the fuel drain on top of the stock filters, let fuel and air bleed out, then close the drain, pump ~10 more times and then crank the engine for about 8 seconds. and I've been repeating this over and over again with no luck.
I opened the line that connects to the IP and hand primed and fuel indeed did start flowing out. I closed this back up, and opened the return line coming back from the injectors, hand primed, and again, fuel came out. So it seems like ive tightened all the fuel line connections that I made.
One thought: for a while, I was opening the wrong drain(it was on the fuel "strainer/dewaterer") which fits into the system before the IP return is teed back into the fuel lines and before the lift pump. Which i now believe was just introducing air back into the fuel lines. I've spent most of the morning working on this and have been cranking the engine over and over again (with periods in between to repeat the priming and let the starter cool). I'm not sure the starter has the same vigor it did when at full charge. Is it possible that I just drained the battery too much while i was doing it wrong that now I don't have the proper charge?
Any thoughts? I appreciate the help
West Coast
1991 Ford B600 Schoolbus
6.6L Turbodiesel running on 2 tank VO
Hotfox pickup, TIH fuel line, coolant wrapped filter, 26 plate FPHE, temp and pressure sensors

You all are lifesavers
every1elsesdoinit
 
Posts: 22
Joined: Sun May 23, 2010 11:38 pm

Postby every1elsesdoinit » Sat Jul 31, 2010 4:59 pm

hmmm so a new development:
I can hand prime the lift pump and fuel will come out of the line which goes to the injection pump. However, when I'm cranking and giving it full acceleration, no fuel comes out of that line.........
which is weird, because my lift pump is a bosch that looks like this:
Image
and I've opened it up before, and I'm fairly sure that the mechanism for the hand primer and for the crankshaft to push fuel are the same......
It looks like the accelerator is all working fine

so im thinking remove the lift pump, give it a look over.... maybe ill have to order a replacement?
I guess it seems a little weird that it would just crap out at the exact same time I re-plumbed all the fuel lines--I'm still suspecting something i did
West Coast
1991 Ford B600 Schoolbus
6.6L Turbodiesel running on 2 tank VO
Hotfox pickup, TIH fuel line, coolant wrapped filter, 26 plate FPHE, temp and pressure sensors

You all are lifesavers
every1elsesdoinit
 
Posts: 22
Joined: Sun May 23, 2010 11:38 pm

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