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Polymerization and filter life
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Hello, i'm on my first 8k miles of SVO driving, in a 1991 F-250 (7.3 IDI) with two-tank system. I've just replaced my VO fuel filter for the 3rd time, and want to figure out if i have polymerization -- or some other problem. I had figured on the first filter plugging rapidly with debris from construction, but was not expecting the next two filter changes to happen so quickly.

I am traveling and collecting WVO as i go. So far i've been mostly able to get grease from (presumably settled) dumpsters, pumping from the middle of the tank. I pour through bag filters down to 1 micron, then pour that into the VO tank in the truck. Because i have little space, my filtering setup is very basic, made of 5-gallon buckets. There is definitely chance for dust or dirt to blow in while filtering or pouring.

I used a steel 'transfer tank' in the bed of the truck for the filtered VO. I have read that steel accelerates polymerization but budget and availability trumped intelligence in that decision. The fuel pickup is a stainless steel 'hot stick'. There's no other heating in the tank, no copper tubing. Because i collect on the fly, the VO in my tank is rarely more than a week old, usually less than a day. I haven't found any info about how long polymerization takes, but it never sounded like an 'overnight' process.

My question, then, is: Does it sound like i have polymerization, based on my ~4000 mi. VO filter life?

And i guess the follow up is: To fix this, do i have any other options besides either stocking up on fuel filters, or buying an aluminum tank?

Thanks for your help!


1999 F-250 7.3 Powerstroke
Vegistroke-type SVO conversion
37g. tank in bed
 
Location: Travelling | Registered: July 28, 2015Reply With QuoteReport This Post
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Most likely your fuel filters are clogging due to excess water content in the SVO. Many dieswel fuel filters are made of a hygroscopic material that swells when even very small amounts of water pass through it. This is meant to warn of excess water in diesel fuel since it can cause expensive damage to Injectors and Injector pumps.

It is also possible that your filter is clogging with fats if the filter unit is unheated.

To check for fats or polymerized wvo cut open a clogged filter so you can access the filter material itself. If it is coated with a layer of something scrape a sample off and heat it. If it melts it is fat and heating the filter may solve the clogging problem. This won't solve the problem with water in your fuel. IF you are doing nothing to remove water after filtering your fuel be prepared for more serious problems with injectors or injector pump sometime in the future.
 
Registered: May 26, 2015Reply With QuoteReport This Post
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Yep. What Dana said.
 
Registered: September 05, 2008Reply With QuoteReport This Post
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Yup, x3



 
Location: coldest N.America | Registered: May 03, 2005Reply With QuoteReport This Post
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Wow, what a great and detailed response. Thank you!

The filter head is heated (made by WVO designs), and i've burned myself on the oil that comes out of the filter so i'm pretty sure this isn't solid fats. But i'll still cut one open to check -- the last clogged filter already went out with the trash so i guess i'll try again in another 4k miles.

It's probably water though.

I'll get into the archives and start looking for a dewatering process that's compact and portable. I'm sure that'll be a challenge.

Thanks again for the great support!


1999 F-250 7.3 Powerstroke
Vegistroke-type SVO conversion
37g. tank in bed
 
Location: Travelling | Registered: July 28, 2015Reply With QuoteReport This Post
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One follow up question i just thought of:

I'm using FRAM PS8132 fuel/water separating filter (http://www.autozone.com/filters-and-pcv/fuel-filter/fram-fuel-filter/729099_0_0/) for the SVO. I chose this because it's also the replacement diesel filter for my truck, and usually on-hand in auto stores across the West.

The filter has a valve at the bottom for draining off water, and a plugged 1/8 NPT port for installing the truck's water-in-fuel sensor. I crack the valve from time to time and only ever see oil come out. I know these filters are NOT reliable for dewatering VO. But i wonder if Dana's observation about filter media swelling and clogging the filter still applies to this style of filter? Why would hygroscopic media be used in a filter that's meant to be drained?

I'm still going to find a way to dewater, but might there be some other problem i need to attend to? Still planning to cut the next filter open and inspect.

Thanks again!


1999 F-250 7.3 Powerstroke
Vegistroke-type SVO conversion
37g. tank in bed
 
Location: Travelling | Registered: July 28, 2015Reply With QuoteReport This Post



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Sounds like you may be using some hydrogenated oil. I find that stuff flows when warm but once it cools, turns into glop that doesn't seem to warm back up quickly. Once clogged, the filter is useless.

Polymerized veg oil smells like paint. They actually make some paint from polymerizing veg oil. It leaves a gummy "chicken skin" build up.


2002 F-250, 7.3l on WVO since '04
'82 VW Rabbit diesel 1.6l na
'83 GMC 6.2l Class C RV
'85 F-350, 6.9l flat bed
'85 E-350, 6.9l cube van
2 Mercedes 300SD's
3 Chinese Changfa-style diesel generators- 12kw, 8kw & 7.5kw
Mitsubishi 3 cyl diesel generator/light tower
Kubota 2 cyl. diesel, water cooled air compressor
Onan 12.5kw air-cooled diesel genset
I run my company entirely on renewable energy including electricity from generators running on biofuels.

 
Location: El Dorado, Ark | Registered: July 04, 2004Reply With QuoteReport This Post
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Water drains and sensors only work for water that is in droplets large enough to drop out of diesel fuel. Since water can also exist as droplets small enough to not drop out the use of a water absorbing filter media is an extra safety measure. If you have a l heated filter you can probably rule out fats or hydrogenated oil as the problem. Polymerized wvo will show up as a sticky material covering the filter media that can be scraped off.
 
Registered: May 26, 2015Reply With QuoteReport This Post
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Always be aware that a minor air leak in the fuel system can cause shorter than ideal fuel filter life, if the filter is under vacuum (lift pump between filter and engine, pulling fuel through the filter).

As the filter becomes more and more restricted, the vacuum increases. As the vacuum increases, the tendency to suck air in at a tiny leak in the system also increases. At some point, the amount of air becomes too great, and performance issues, starving, stalling appear.

The user installs a new filter and all is well, until next time.

The vast majority of issues with WVO systems are not with the oil, the injectors, the pump, the filter, etc. they are with air leaks.

On new systems, especially for the first time installer, it is very common to have air leaks, and even a system that seems fine at first can very often need to have every clamp and fitting checked and tightened just a bit more after the first few weeks of operation.

I'd suggest you go over every clamp, every fitting, tighten a bit, and check also for hose cuts at clamps that were perhaps installed too tightly, also check for hoses on the supply side that improperly adapted to a smaller hose and may be clamped to an "out of round" shape.

And if you did not use lots of Permatex White on all threaded fuel system connections, you make have to re-do them.

4-5000 miles on a truck on dumpster grease per filter element is not too bad, given the size of that element, and your filtering arrangements, but you may get better filter life by checking the system over thoroughly for air leaks at this point.


Edward Beggs
PlantDrive(tm) International
plantdrive.ca@gmail.com
http://www.PlantDrive.ca
SVO Consultations; Component/Kit Supplier; SVO Conversions; since 1999.
 
Location: Salmon Arm, BC, Canada | Registered: November 23, 2001Reply With QuoteReport This Post
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Also, on your particular truck, if you are running both fuels through the original fuel filter and using it as your diesel filter, you should install a new original diesel filter when you do the conversion and then thereafter as needed. If it is getting plugged, and now has a film of veg on it, it could able to flow diesel but not veg.


Edward Beggs
PlantDrive(tm) International
plantdrive.ca@gmail.com
http://www.PlantDrive.ca
SVO Consultations; Component/Kit Supplier; SVO Conversions; since 1999.
 
Location: Salmon Arm, BC, Canada | Registered: November 23, 2001Reply With QuoteReport This Post
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Lastly, that is not a very big filter element for the veg side of the system. The more media there is, the longer the filter element will last. You might want to look at going to a physically larger element, something that is cost-effective and does not need to be changed as often.


Edward Beggs
PlantDrive(tm) International
plantdrive.ca@gmail.com
http://www.PlantDrive.ca
SVO Consultations; Component/Kit Supplier; SVO Conversions; since 1999.
 
Location: Salmon Arm, BC, Canada | Registered: November 23, 2001Reply With QuoteReport This Post
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This is all very helpful. Based on what Dana and Edward are saying, i don't think the issue right now is polymerization. Really seems like water. I'm disinclined to think it's hydrogenated oil since i heat to filter, so if it were going to glop up after reheating, it would have done it in my filter socks. I was struggling to find grease for my last fill-up so i broke my rule and collected cubies straight from the fryer instead of pumping from a settled barrel. Now the new VO filter is already plugging - i bet that stuff was wet as heck.

Yes, my pump is after the filter, so it will pull in air when the filter plugs. And yes, i did spend my initial months fixing air leaks (the truck is nicknamed 'bubbles')! Now tubing and barb sizes match up, all threads are white-permatex'd, and all plumbing is clear tubing, which yes, i had damaged by over-tightening the clamps (now replaced with new tubing). If i feel engine hesitation i pop the hood and watch for the bubbles; when the filter is clogged i see them shoot out of the filter head and into the pump. If i see them elsewhere i look for loose fittings, but these days the only place i see them is coming from the filter head, so i'm reasonably sure my issues are filter-related.

'Bubbles' just blew a brake line so i have a few days of non-driving to think about what to do. I'll definitely switch to a larger, cheaper filter for the VO side (thanks for the suggestion Edward). I know the grease already in the tank is wet, so i could either rely on the new VO filters to catch that or pump it out and dry it...somehow.

There are old posts on here about a granular desiccant called "Quick n dry"...but nothing recent and the links in those posts are dead; suppliers no longer offering it. Maybe it was ill-suited for making bio or large-scale operations, but at my volumes (<50 gal./week, max), pouring the filtered grease through a desiccant column would be a very workable fix. Looks like it's either that or a centrifuge...which is a whole lot of $. Do y'all know if there's a desiccant i can use, or was that approach determined to be no good?


1999 F-250 7.3 Powerstroke
Vegistroke-type SVO conversion
37g. tank in bed
 
Location: Travelling | Registered: July 28, 2015Reply With QuoteReport This Post



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quote:
There are old posts on here about a granular desiccant called "Quick n dry"...but nothing recent and the links in those posts are dead; suppliers no longer offering it. Maybe it was ill-suited for making bio or large-scale operations, but at my volumes (<50 gal./week, max), pouring the filtered grease through a desiccant column would be a very workable fix. Looks like it's either that or a centrifuge...which is a whole lot of $. Do y'all know if there's a desiccant i can use, or was that approach determined to be no good?


I use "Quick n dry" for final 'polishing' to remove water from my fuel. I've confirmed it's effectiveness with a carbide manometer. Similar hygrophilic polymers are available as 'water crystals'.
http://www.watercrystals.com/



 
Location: coldest N.America | Registered: May 03, 2005Reply With QuoteReport This Post
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Thanks John Galt, that's exactly what i was hoping to find out, if regular "water crystals" will do the job. I will pick some up and reprocess my wet VO and then integrate that dewatering into my portable filtering setup.

After talking to the shop, "bubbles" needs a lot more than just a new brake line. It might be a while before i'm able to test the effectiveness of these changes.


1999 F-250 7.3 Powerstroke
Vegistroke-type SVO conversion
37g. tank in bed
 
Location: Travelling | Registered: July 28, 2015Reply With QuoteReport This Post
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quote:
I pour through bag filters down to 1 micron, then pour that into the VO tank in the truck


I doubled my filter life by filtering to 1 micron _twice_.
Also are your filters absolute rated? ie 97% captured?
Are you cold ( ambient temp ) filtering your wvo, or is the wvo warmed or thinned with solvents ?


1-tank Elsbett VW TDI , 220,000 WVO miles.
http://ctbiodzl.freeshell.org/votdi.html
and a '92 F-250 with only a FPHE
 
Location: Ct,USA | Registered: November 19, 2001Reply With QuoteReport This Post
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The bag filters are only nominal-rated. I heat one cubie at a time, then pour it through the bags and capture it in a 5-gal. bucket. My stack is currently 75/50/25/10/5/1 micron; i had figured a single pass through that wouldn't leave much for the 10u engine filter to catch, but based on your experience i probably should try multiple passes or getting absolute bags. Since i evidently need to change my filtering process anyway, it makes sense to do something about that while i'm at it.

My last plugged filter is in the truck, at the shop. Once i'm feeling better i'm going to ride over there and grab that filter along with my hacksaw, to see what it looks like inside.


1999 F-250 7.3 Powerstroke
Vegistroke-type SVO conversion
37g. tank in bed
 
Location: Travelling | Registered: July 28, 2015Reply With QuoteReport This Post
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This thread's not quite dead yet...

I ended up retiring the 1991 truck. After a brake line blowout (they're all rusted), the transmission crapped out and the radiator is trashed. I can't really tow with it anymore and it's in such bad shape that it's not worth throwing more money at...so i removed the WVO equipment and got rid of the truck. Got ahold of a 1999 Powerstroke F250 and i'm working on converting that.

I've replaced my 'nominal' filter bags with absolute bags. Still not sure how to dry the oil better; i've gotten some desiccant crystals and tried dangling them in my tank in a 'tea bag' but that's pretty

I finally got around to cutting open the veg oil filter from the old truck the other day. I've never actually cut open a filer before and i made a mess of it. I'm looking at the paper filter and...i guess i don't know what i'm looking for, to see if water was a major factor in the rapid filter clogging, or if i just needed to filter better. Photo (should be) attached; i'd appreciate feedback. Thanks!


1999 F-250 7.3 Powerstroke
Vegistroke-type SVO conversion
37g. tank in bed


ImageCut_filter.jpg (31 Kb, 6 downloads) Photo of cut filter interior
 
Location: Travelling | Registered: July 28, 2015Reply With QuoteReport This Post
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From the look of the filter your prefiltering setup is letting more particulates through than desired. If you are using bag filters to prefilter and they are merely hung and filled the pressure of the wvo inside will cause the filter material to stretch outward. This compromises the micron rating of the bag filter.
 
Registered: May 26, 2015Reply With QuoteReport This Post



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Dana, thanks for checking out my photo!

Now that i'm driving a DI diesel, injectors are a lot more expensive than they used to be and i'm freaked about water content. So i'm planning on pouring my warmed grease through a basket strainer filled with desiccant, laying on top of my prefiltering setup. I just burned up the last of my old WVO so i'll be using this on the next batch that i filter.

All my old filter bags have clogged at this point and are replaced with absolute-rated bags. Multiple passes are possible but quite inconvenient since my setup is mobile, and i'm already carrying a lot of 'extra' cubies and such. So i'm hoping the absolute bags help enough that i can avoid multiple passes. I also switched to a larger filter on the truck (a cross-up with the long Donaldson used in the Vegistroke kit).

I'm also overhauling my collection rig; it is built around the crappy harbor freight utility pump. My first pump lasted over 6 months but then started to fail. The replacement failed directly out of the box (when i disassembled it, it looked like it had been abused and then returned). They are crummy pumps but for the money it's hard to beat. I'm keeping a spare on hand at all times and use the extended-service plan so i'm basically getting new pumps every few months for nothing. I hate how wasteful it is, but can't see my way clear to spending hundreds on a good-quality replacement. I have at least updated my collection rig to include a couple pre-strainers to help protect the pump (and hopefully i won't go through as many 50u bag filters).

Yes, my filter bags are hanging. They are nested inside one another, 50-25-10-5-1. So the 50u bag probably bears the brunt of the 'stretching' issues, as its the one that gets "filled" with hot grease. The 1u bag should not be seeing much pressure to distort it. I can see where having a full bag, unsupported by a basket, would stretch it out. Do you think the nested bags i'm using are just as big a risk for stretching as single, unsupported bags?


1999 F-250 7.3 Powerstroke
Vegistroke-type SVO conversion
37g. tank in bed
 
Location: Travelling | Registered: July 28, 2015Reply With QuoteReport This Post
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I think that even nested the way you describe the outermost bag will experience stretching and some micron rating compromise. If you can find an inexpensive way to incorporate an exterior support cage it might help. Perhaps adding a large micron filter bag as the outer layer might work.

I am skeptical that simply pouring through a basket strainer with desiccant will significantly reduce water content in your wvo. In my experience circulating through a desiccant filled section of pipe had a measurable effect. My most effective water content reduction came when I circulated wvo through a pipe section filled with calcium carbide but since the reaction produces a flammable gas extreme care must be taken to avoid the possibility of that gas causing an explosion.

Consider using a vacuum/pressure tank to move wvo. 12v vacuum and pressure pumps are available for mobile processing rigs. Not as cheap as hand pumps..but they last and last.

Hope this helps..
 
Registered: May 26, 2015Reply With QuoteReport This Post
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