Pollock valve problems on dual tank WVO conversion

[sunnyintx]

I've searched and searched, and now I need you guys to help me figure out what's wrong.

1984 300D, came with the dual tank conversion. New to me in mid-March. It worked great when I got it -- two three-port Pollock valves controlled by two toggle switches where the ashtray used to be -- one valve "chooses" the source of fuel (main or auxillary tank), and one "chooses" the destination for the return in order to properly purge the lines before shut-down. There's a bunch more to the system, but I won't bore you with it unless someone says it's needed to address the problem, which I think is electrical, my weakest area. Since it seems electrical problems are often gremlin-like with lots of seemingly unrelated stuff failing or going haywire, I'm going to give a fair amout of detail on the issues we've had since getting the car.

It had a short that was blowing out the horn fuse, and also shut off the power antenna. I hadn't gotten around to addressing that problem beyond replacing the fuse pretty often when the transmission began to fail, and we ultimately ended up replacing the tranny. We did not do the work -- we had it done by an indie we've used before that we found through the forum. He's gotten a bit flaky, so we're shifting away from using him for everything, but the transmission install seemed good with a couple of small glitches that were easily corrected.

On a subsequent road trip, we found that the fuel tank selector switch was not working -- the auxillary tank was full, and stayed that way! We also noticed a slight leak out of the auxillary tank cap. When we got home, we drained about 3 gallons out of the aux tank thinking I'd perhaps overfilled it, and the leak stopped. For a while.

The PO had bypassed the CCU with some weird system connected to a toggle switch to direct drive the blower motor and the compressor. He'd disconnected it from the power source before I got the car, but the wiring was still in place. I managed to restore some of it to where it was supposed to be, but couldn't find some of his handiwork, so I took it to our electrical guru. He undid the rest of the bypass and returned it to it's stock condition, and as soon as I replace one of the hoses, I should have A/C. While our electrical guy had the car, I told him about the problems with the switches for the Pollock valves, and asked him to try to fix it. He told me he had -- that the 10 amp fuse had blown and on replacing it everything seemed to be fine. [I failed to ask him to find the short affecting the horn and antenna -- I just forgot, since the fuel issue and A/C had become the really distressing problems.]

However, while driving the 100 miles back from his place, I tried switching over to the aux tank (source) and found I had no fuel at all. I switched back immediately and the car recovered. Later, I tried it again, and the car starved for fuel and even on switching back to the main tank, it took me a good 10 minutes to get it started again. That problem is new since the electrical work -- before the electrical work, the valve just wouldn't switch. Now it seems to be closing both ports when I toggle the switch.

In neither instance did I move the return switch from main to aux -- the return should have been going into the main tank. But the leak was back -- diesel (the aux tank has diesel in in from being away on a road trip w/o access to veg oil) dripping from the filler cap.

I finally figured out that the return selector switch, while in the "main" position (which should be returning fuel to the main tank) was returning fuel to the auxillary tank, creating an overfill and thus a leak. I have only recently figured this out, so I haven't tried switching the return to auxillary to see if it was somehow reversed during the tranny install.

This is the thing -- the only thing done to the car between the Pollock valve switches working fine and the switches not working right was the tranny install. I suppose the Pollock valves themselves could have failed, but I don't know what the symptoms are for that. This seems like a problem with getting the proper signal to the valves, but tracking down electrical gremlins is not something I'm really competent to do. As I said, our indie has become more than a little flaky in recent months, and I know for a fact that he won't take responsibility for this. So I need to figure it out without him. I don't think he'd deliberately do anything to screw it up, but what might he have done in the process of changing out the tranny that could have resulted in this problem? Obviously, there are subsequent problems related to the electrical work (the fuel starvation came after the electrical work), but since the electrical guy is unfamiliar with this conversion, I'll need to give him some direction when I take it back to him.

Any ideas or suggestions you have will be much appreciated. A referral to a good indie in the North Texas area who won't scalp me would be nice, too.....!

Thanks -- looking forward to your replies!!

Sunny

[vstech]

pollack valves are really bad items. they are known to fail. frybird sells (if you can get ahold of them) fine quality valves. that is where I would start.
I would bypass the valves altogether and run on diesel until I got this sorted out.
compare the two valves visually... no comparison

John

[sunnyintx]

Thanks, John. You're right -- there's no comparison. Frybrid's look amazing. In some of my research pre-posting, I found a lot of folks saying the solenoid Pollock valves were prone to failure but the motor driven ones were good, but I can't tell the difference looking at mine -- I've no idea which they are.

I also looked at the 6-port v. 3 port thing -- it seems that the 6-port would purge oil into the main tank. Not that it would be much of an issue here in Texas, but the whole idea of a two-tank system is to keep the veg oil out of the main [diesel] tank.

So you think both my valves are fried? Weird that they'd both go at the same time, and right after other work on the car, but I know such things can happen.

Thanks again. I had already planned to drain the aux tank completely this weekend (put it in the main, since it's diesel anyway), run on diesel as I have been for the last several weeks (ouch!), and keep an eye on the return issue until I sort this out. Sheesh! If it's not one thing, it's another!

[WD8CDH]

Even the motor driven pollack valves are failure prone at the temperatures in a WVO system.

[Diesel Dan]

To test your valves, have someone operate the switches with power on, but the engine not running, while you are inspecting the solenoid valves. My pair of 3-way solenoids (made by Greasecar) make a clicking sound so I know they are working. If you hear nothing, then use an electrical tester to see if you are getting power to each solenoid at the appropriate time.

In order to determine that they are selecting the proper supply and return sources, disconnect your valve intake fuel hoses and put them in containers of veg oil, then use a hand operated vacuum pump to suck through the exit hose. Watch to see which container is getting emptied. This will tell you whether or not the valve selector switches are doing what they are supposed to be doing.

By the way, my solenoid valves are set up so that if no power is applied, they default to diesel supply and diesel return. I have a 3-way rocker switch, so if the switch is in any other position than center, then power is being applied to one or both solenoid valves.

There is also a chance that you have large air bubbles/pockets in your fuel system somewhere.

Hope this helps. Good luck!

[sunnyintx]

Thanks, Ron. That makes sense -- temp being the missing piece of the puzzle on why these things fail when we're not using them to do anything they weren't meant to do.

Dan, I'll try your suggestions. I will likely have questions, and won't get to it until next weekend since this one's already spoken for with way too much to get done! I like your description of your switch set-up -- was that a Greascar kit item, or can you tell me how that was done? Yeah, later -- I've got enough on my plate right now without trying to redesign the system!

The road trip was to Austin -- I shoulda taken my laptop along and asked you then!! Will you be going to the Centerville GTG at the end of this month?

[cgunderm]

Originally Posted by WD8CDH

Even the motor driven pollack valves are failure prone at the temperatures in a WVO system.

I agree, they are crap. I had a motor driven 6 port in y 1985 300D, and one day it started quitting on me. Overnight I had a huge diesel spill because the purging diesel overflooded the veg oil tank, and I was woken by my neighbor after midnight informing me that the whole parking lot was covered in diesel fuel. This was when I still lived in a condo association in town with some nasty prissy neighbors (not the one who told me). I went out and got the famous clumping cat litter to start containing it, was up half of the night, man did I curse this thing. It kept overflowing until I cut the lines. It had gotten stuck open and the vacuum in the lines kept pulling diesel fuel into the veg tank. These valves don't deal well with higher fuel temperatures, and apparently can't handle biodiesel either. I don't know why anyone would still promote them.

[sunnyintx]

OK, THAT sounds awful!! In 37 acres of woods, my only prissy (I think you've probably got an extra letter in there...) neighbors are 'coons, 'possums, and the occasional bear, but I don't want to spill that much diesel (or oil) anywhere, and when I'm in Dallas where I do a lot of my work, there really are prissy neighbors!!

So what did you replace the Pollock with? The Frybrid valve or something else?

[Diesel Dan]

Originally Posted by sunnyintx

Dan, I'll try your suggestions. I will likely have questions, and won't get to it until next weekend since this one's already spoken for with way too much to get done! I like your description of your switch set-up -- was that a Greascar kit item, or can you tell me how that was done? Yeah, later -- I've got enough on my plate right now without trying to redesign the system!

The road trip was to Austin -- I shoulda taken my laptop along and asked you then!! Will you be going to the Centerville GTG at the end of this month?

Yes, the switch and solenoid selector valves are all part of the Greasecar kit. Greasecar sells them as stand-alone items. But no, I don't think I'll be able to make it to Centerville this month.

[runnysucklehose]

I have not bought anything from this company so I cannot recommend them, but they do sell nice valves, among other things...The centrifuge filters, davco heated filters, and Hot Fox heat exchangers they sell are all products I can recommend because I use them, but they are all available for purchase direct from thier manufacturers.

http://www.vegpower.com/order/prodpage.cfm?cat_selected=&product_selected=267

I would also follow Diesel Dan's advice before replacing your existing valves, he is right on.

When I was testing out the on my Isuzu box truck's conversion I found out the hard way that I had my return lines crossed. Diesel fuel was returning to my veggie tank located in the truck's box, the fuel mixture was leaking out of the front and sides of the box onto the highway. Some guys in a beat up pinto drove up along side me and started pointing so I pulled over and saw what had happened. Good thing I keep a large supply of Oil-Dry with me...

I'm just glad what spilled was mostly WVO.

Next time I do a conversion I am going to by several different colors of hoses to keep everything sorted out.

[sunnyintx]

Yeah, different color hoses makes good sense. I'd be totally lost except the guy who installed these actually has arrows painted in white on each hose to show direction of flow, so that's helpful. That's assuming it's right.....

I think I'll modify your idea -- when I do Diesel Dan's test, I'll use colored electrical or duct tape around the lines as I figure out which are veg oil and which are diesel....

Thanks for the link -- I haven't visited Vegpower's site in a long time, but it looks like I need to do some shopping soon. Greascar's valves look pretty good, and Frybrid's & Vegpower's look the same -- same price, too. I'm really kicking myself for not thinking of the fuel temp creating problems with the Pollock valves!

[cgunderm]

Originally Posted by sunnyintx

OK, THAT sounds awful!! In 37 acres of woods, my only prissy (I think you've probably got an extra letter in there...) neighbors are 'coons, 'possums, and the occasional bear, but I don't want to spill that much diesel (or oil) anywhere, and when I'm in Dallas where I do a lot of my work, there really are prissy neighbors!!

So what did you replace the Pollock with? The Frybrid valve or something else?

Greasecar valve. The "new" one (they've used it for the last 2 years or so, and sell it separately, too, for about $60)
I got rid of the whole purge function, just one three port valve, and just drive a couple of miles on diesel until there is no more oil in there. I just didn't want to give any bad valve a chance to do that to me again, ever. Even though my neighbors are the same as yours now, and I live on 32 acres of woods, too....

[Rick H]

been using the same pollack 6 way valve 4yrs no problems.

[Don DS]

Plantdrive system stands behind the pollak 6-port valve and gives a 5 yr warranty on them because they have seen so few failures.