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no solenoid filter flush?
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In an effort to keep this truck conversion (6.2 L chevy) as cheap as possible I have tried to devise a system with no solenoid, but using the two needed lift pumps to do the trick. I want the truck to be cold weather tolerant so the veg filter needs to be flushed by diesel.

Do folks think the design below will work?

The pumps are both one-way, pumps 5-9 psi, allowing no backflow even when off. The switch would be a double pole/single throw I believe, so only one switch needed. The HIH is copper and is before the Veg pump. All veg lines and return loop hose is 3/8". The Veg filter is a 10 micron Goldenrod from McMaster, diesel filter is stock.


2003 VW Jetta GLS TDI Wagon:
Looped returns after filters, 2 Micron Racor, Nylon 6 HIH, Veg Therm, Nichrome Wrap, B100 when over 50 F.
1989 Chevy 2500, 6.2 L, V8, both tanks looped, copper HIH.
B50 when over 50F


Imageno_solenoid_schematic.jpg (47 Kb, 70 downloads)
 
Location: Moretown, Vermont | Registered: March 23, 2003Report This Post
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YOu will want to incorporate a diesel return line to flush out any air...even if it is just a manual valve on a tee. A solenoid valve will allow a more convenient purge in very cold weather. Leave diesel on loop for a few minutes and then switch to pure diesel and return to tank.

You will want to remember to HOH all veg lines to thaw them out in cold weather. And you may want to consider straping the vegtherm to the filter and insulating it with high temp ceramic inslation to warm the vegfilter. Even running diesel through it may leave a coating of grease on the element which will prevent the vegoil from initially passing through in cold weather unless it is warmed first.

This may work..I have used a similar design with good results...but cold weather can be a bear to deal with. Small details make a big difference.
 
Location: Central MN..Brrrrrr! | Registered: November 06, 2001Report This Post
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Hey there! I'm in the middle of converting a 6.2l Chevy as well, an '82. I'm curious about two things. Hell, they are probably addressed somewhere in this forum but there is just so much here!

Why two pumps and why two filters? Why not have both fuel lines feed stright to the valve, then the pump (I assume there is only one in there now and that you are adding the second -- or perhaps you're adding two new ones and skipping the one that's in there completely?), then to a shared filter, then the IP.

I am hoping to rig mine so there are actually three modes the truck can be in: 1- start-up: diesel with a return to tank, 2- SVO, looping back and T'd in just before the filter, 3- purge: diesel, but not returning, rather following the same loop back that the SVO follows so the whole thing is cleared and ready for start-up, and hopefully allowing any air that gets in during the SVO stage to be worked out when I switch back to start-up mode and it returns to the diesel tank.

Then if you were to add a vegtherm as Dana suggests, I assume it would go right before the filter, perhaps attached to it as Dana suggests to heat it. Personally I am holding out for Dana's how-to kit on converting the filter to serve as a high-temp heating unit - simpler, cheaper.

I'm also planning on doing thorough pre-filtering so the burden on teh single filter should be minimal.

I'm new to this though, so don't take my word for any of this -- hold off and see what the vets say in response!

Jeff Golden
Tivoli, NY


Jeff Golden
15,000+ miles on SVO, 3500+ on B100 - '82 6.2L C10 Chevy Pickup -- til the transmission died... (non-VO-related)
Common Fire Foundation
www.commonfire.org
 
Location: Hudson River Valley, NY | Registered: March 24, 2004Report This Post
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OK, I have a slightly altered plan, as I realized that to get at the line between the stock diesel filter and the IP I have to remove the intake manifold. Don't want to do that so I am trying to go around the stock filter altogether (using the ports on the mounting bracket for access). My 6.2 is a version with the model 75 filter that is on the maifold itself, not remote. Keeps it warn but a major pain the ass.

Is there a machanical lift pump I need to be worried about here?

Thanks!
Ben


This is what I am thinking now:


2003 VW Jetta GLS TDI Wagon:
Looped returns after filters, 2 Micron Racor, Nylon 6 HIH, Veg Therm, Nichrome Wrap, B100 when over 50 F.
1989 Chevy 2500, 6.2 L, V8, both tanks looped, copper HIH.
B50 when over 50F


Imageno_solenoid_schematic.jpg (24 Kb, 49 downloads)
 
Location: Moretown, Vermont | Registered: March 23, 2003Report This Post
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Ben
unless your engine is quite a bit different from mine (doubt) I didn't have to remove the IM. I did cut that rubber portion to change the plumbing though. Look again!

The stock lift pump is mechanical ; located On the passenger side of the block PITA to get to especially with a Turbo.


1988 TurboDiesel SVO Suburban converted from gas
1991 Jetta TD SVO coupe.
1987 Vanagon SYNCRO//Westy graft//TDI SWAP//
 
Location: Essex , VT | Registered: March 20, 2002Report This Post
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Dana, what do you mean by "manual valve on a tee"? Where would this mount? Cheap part available I imagine?

Big Swifty...

Is your filter mounted to the back of the manifold?

I'd love to see your rig sometime...

What's your phone #, maybe I could see your truck sometime, or just chat on the phone - I am near the end of this conversion, but think there are a few key issues I need to address (air in the injection lines, lift pump arrangements.) Send me an email at info@bsr-vt.org if you'd like...


2003 VW Jetta GLS TDI Wagon:
Looped returns after filters, 2 Micron Racor, Nylon 6 HIH, Veg Therm, Nichrome Wrap, B100 when over 50 F.
1989 Chevy 2500, 6.2 L, V8, both tanks looped, copper HIH.
B50 when over 50F
 
Location: Moretown, Vermont | Registered: March 23, 2003Report This Post



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Manual valve on a tee.

I beleive Greael uses something like this.

It is mounted in the return loop with the tee alloing the fuel to pass through the strait leg of the tee..and the valve on the other one. The valve is plumbed to either tank..I prefer the vegoil..so if you need to purge bubbles from the loop the valve is simply opened up so air and excess fuel can escape back to the tank...and then closed when the air has been removed completely. Somce folks even leave the valve cracked just a tad so bubbles can escape anytime. If diesel is to be used for a longer period than just start/stop purges the valve is completely closed to prevent the vegoil tank from filling with diesel.

Hope this helps,
 
Location: Central MN..Brrrrrr! | Registered: November 06, 2001Report This Post
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Better yet, IMHO, is to use a small tee (1/4" or 3/8") in a return line and needle valve to allow only a very small amount of return fuel.

Put it at the highest point in your system supply line and any air in the system will go back to the tank.


Good Vegging and God Bless!!
24,000 veggie/blend miles and counting! Smile

Kugel

1991 Ford F350 7.3LNA Diesel ZF5/5-speed tranny: Currently running unheated 75/25 WVO/RUG Blend [WVO - 5 micron prefiltered and regular unleaded gasoline mix] + Power Service Diesel Kleen 6-point Cetane Booster; removed mechanical lift pump, added single electric fuel "push" pump (NAPA #6101049), back near tanks; Fram #G15 (10) micron inline filter at main Fuel Filter inlet; looped IJP return line Tees back into Fuel Filter inlet; Injector return lines still go to stock selector valve and tanks; Fuel Filter Air Bleed tees back into Injector return line. So far, she's running GREAT!!
 
Location: South Alabama, USA | Registered: October 20, 2002Report This Post
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Thanks Dana and Kugel,

I think the return side options is probably better as I can get two birds with one stone - air will all end up in the return but could end up in each of the 2 supply lines...

I am suprised that all the air would go to the tank through the T. It seems some might and some might also just continue with the fuel into the IP again...


2003 VW Jetta GLS TDI Wagon:
Looped returns after filters, 2 Micron Racor, Nylon 6 HIH, Veg Therm, Nichrome Wrap, B100 when over 50 F.
1989 Chevy 2500, 6.2 L, V8, both tanks looped, copper HIH.
B50 when over 50F
 
Location: Moretown, Vermont | Registered: March 23, 2003Report This Post
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Ben

Sent you an email


1988 TurboDiesel SVO Suburban converted from gas
1991 Jetta TD SVO coupe.
1987 Vanagon SYNCRO//Westy graft//TDI SWAP//
 
Location: Essex , VT | Registered: March 20, 2002Report This Post
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