20 gallons of 20:80 WVO and diesel = clogged fuel filter - Page 4 - PeachParts Mercedes-Benz Forum

BoostnBenz · #46 07-28-2004, 11:29 AM

I wouldn't say it is a common problem but is quite doable with enough neglect. Easiest way to cavitate anything is by having water in the fuel!

TonyFromWestOz · #47 07-28-2004, 11:31 AM

Thanks BnB

driad_98 · #48 07-28-2004, 01:00 PM

ack... new filters, new primer pump, same old problems. Not to mention the booster that I got from the yard is defective. <sigh> So now I'm back to square 12. I'll pick up a known good booster from Silver Star here in Oakland and install it (the 'new' one is way worse than the old one) today, but I'm kinda stumped on the WVO problem. I switch over and within about 1.5 minutes at highway speed she chokes up and practically shuts down... WOT, and a switch back to diesel brings it back in what seems like about 5 minutes but I'm sure is only 2 or so. Limping along on the bay bridge at 35-40 for 2-3 minutes sucks. oof. So yea... I'm frustrated because the system ran great to LA and back then on another trip, about 300 miles no sweat. Worst part is that when I pull over quick to check it out, there's no air in the system up to the fuel pump. I guess it could be sucking after the fuel pump, thus filling the OE filter with air, thus the long restart time when I switch back to diesel. I guess I'll go through and clamp EVERYTHING and tighten what's loose. I had a bad night on the bridge last night, about to throw in the towel... I'm better now. <sigh> Anyone have anything for me? Anyone in the BA wanna come help me troubleshoot it? I'm lonely.

Ash

sunnyintx · #49 07-28-2004, 02:11 PM

Ouch!! Surely someone on here can help. I'm just watching you to see how it all comes out, since we're in the process of switching over our '84 and '85 to use WVO. I need to learn from everyone else's mystery ailments, so I can avoid as many problems as possible. You know the old rule: learn from the experiences of others -- you won't live long enough to have all the experiences yourself!

Good luck!! Not that it helps, but my fingers are crossed!

Sunny

driad_98 · #50 07-28-2004, 04:33 PM

Oh, Sunny, I think it _does_ help!

Let's see... it's running again, I had popped a fuel line and run it dry, so happy I didn't have to get out and pump while on the bridge... she primed herself when I switched back to diesel. I think an aux fuel pump would aid me, too, though, because the power's down and it stumbles under heavy accelleration... I'm thinking it's just not pulling enough fuel through that little 1/4 line from the trunk... I may try to re-install the loopback return now that I think I have my air leaks under control... I'll let you know how that goes.

You can get all my trials, or most of them, by searching for posts under my name.

Thanks for your support. Now to go install the NEW(er) brake booster.

Cheers!

Ash

sunnyintx · #51 07-28-2004, 05:21 PM

I keep wondering about these....

Even with a larger hose, won't I have to step back down to the 1/4 inlet to the primer pump/IP? If it's the viscosity of the oil slowing things down, do we gain that much with a larger hose, considering the bottleneck when we get back into the regular fuel system? It seems like it would get there faster in more volume, but still be difficult to "pull" through that little inlet. Comparing sucking an icee through a straw vs. sucking it through a straw-sized hole, it's a little easier, but is it enough easier?

Just a random thought I've been turning over on this issue....

Better thoughts -- or experiences! -- would be welcome.

Sunny

driad_98 · #52 07-28-2004, 05:34 PM

I think pulling higher viscosity oil through the small straw is harder than pulling low-viscosity (heated) oil through the small hole... as the oil gets closer to the IP it gets hotter and hotter.

Brake woes have me busy. Good luck!

Ash

BoostnBenz · #53 07-28-2004, 11:11 PM

The stock line is 8mm if I recall correctly, that makes it .32" the size line you are using is only 61% of the cross sectional area of the stock line. However by defenition of viscosity it will flow slower which implies if anything you want a larger line as the fluid requires more energy to shear it and allow it to flow from the tank to the IP like we want it.

danalinscott · #54 07-29-2004, 01:23 AM

I have helped with nearly 200 vegoil conversions and design and fabricate conversion parts/components. They all thin vegoil with heat application from tank to filter. Even though you mix vegoil it can separate. This is especially so for WVO (waste vegoil) which can separate out some nearly solid stuff which can be difficult to pull through 1/4" id line. Several solutions exist short of a two tank conversion....

1. Settle your wvo before you prefilter it..and use only the stuff that is in the top 3/4...the lightrest fraction. Use NO fat.

2. Thoroughly mix the wvo with the diesel fuel. Don't rely on "tank slosh" to do the job...it won't. If you allow the mix to sit unused in the tank for more than a week..especially at temps under 50*F remix it before using. How? Slip a small tube down the fill tube to the bottom of the tank..then use either an electric fuel pump to circulate the mix..or use compressed air to bubble mix it in the tank.

3. Install a low pressure electric fuel "boost" pump as near the tank as possible. I like Facet/Purolator for durability. They make models with diffferent pressures...use one that dooes not exceed the stock one. One major danger in installing an electric boost pump inline with a mechanical one is if the diphram on the mechaincal one developes a leak you will probably fill your crankcase with the wvo/diesel mix before you notice. This may be very bad....and your engine can be toast.

4. Install a heated fuel line. These are pretty easy to fabricate with just a ustility knife and ruler. This will warm the mix enough to allow it to flow easily...and only costs about $3 a foot.

Another thing that can happen is that fat can solidify and then coat your filter element. This causes your engine to starve for fuel. A small glowplug based fuel heater installe dright before your filter can melt the fats and allow them to easily pass through the filter element.

If you would like more info on any of these suggestions please contact me directly at danalinscott@yahoo.com

hope this helps

Dana

BoostnBenz · #55 07-29-2004, 09:31 AM

Quote:

Originally posted by danalinscott
2. Thoroughly mix the wvo with the diesel fuel. Don't rely on "tank slosh" to do the job...it won't. If you allow the mix to sit unused in the tank for more than a week..especially at temps under 50*F remix it before using. How? Slip a small tube down the fill tube to the bottom of the tank..then use either an electric fuel pump to circulate the mix..or use compressed air to bubble mix it in the tank.

I've heard before that in is a little as 3 hours the two seperate even after being thoroughly mixed, any truth in this?

TonyFromWestOz · #56 07-29-2004, 10:22 AM

I have tried mixing WVO and Petroleum Diesel and have not had any problems with separation of the oil from the diesel.
I am currently using a 50:50 WVO:biodiesel blend in the main tank of both my wife's and my MB300Ds, with no sepeartion issues.

BoostnBenz · #57 07-29-2004, 11:06 AM

Good.

Thanks Tony.

driad_98 · #58 07-29-2004, 01:10 PM

Thanks for the info about the stock sizes and the suggestions for visco-lowering. As it sits right now, I have a heated second tank, and heated line all the way up front to the filter, which is unheated (currently). Does the boost pump, in-line, end up in the tank, or outside of it? What's the optimal PSI for this boost pump? I think this could be the answer for my application. What should I expect to pay? Where can I buy one? Thanks a ton!!

Ash

Fredmburgess · #59 07-29-2004, 04:42 PM

My experience is similar to Tony's. I've got an '84 300D with a two tank system but have been running my '83 300SD with filtered WVO directly in the stock tank. In fact, I just drove 800 miles on nearly 100% WVO in the stock tank. All highway miles, 75-80mph, no problems whatsoever. I'm up to 1600 miles this week and am now running on about a 50/50 blend of WVO/diesel in the main tank - just a bit more smoke at startup in the morning (60F this morning near Watertown, NY). I'm getting 100% peanut oil that's been used to cook potatos only, so no tallow. Filtering through a 10 micron bag filter, then pumped through a 10 micron fuel filter with water trap enroute to the main tank.

So far the '83 has run great with no starting, acceleration, or filter problems (stock filters). It will get a second, heated WVO tank before the weather turns. I think the two keys to success are effective settling/filtering of the WVO and of course elimination of any air leaks in the connections.

Cheers all!

danalinscott · #60 07-29-2004, 04:42 PM

HI Ash,

The electric pump (I like Facet) can be had a NAPA for arounf $35. I raccomend checking what psi the stock pump should put out and staying under that. They work best if placed close to the tank.

But...if you have an unheated filter..I suspect this is a problem. Fats tend to quikly clog the element on an unheated filter and the IP soon cannot pull enough fuel...and the engine starves. A vacuum gauge installed in a tee between the filter and IP will tell you if this is actually the problem. Normally there is no vacuum there...if there is the filter is clogging. And if your filter is unheated or the vegoil passing though it is under 75*F I would bet it is clogging with fats. A heated filter melt these fats allowing them to pass through the element easily. Before you install a boost pump I strongly urge you to check to see if there is a vacuum between the filter an IP when running down the road. A boost pump will not fix this..and remember the danger of toasting you engine with a boost pump installe inline with a mechanical pump. Why risk it ?

I currently offer a simple "kit" and directions to convert a "goldenrod" fuel filter to an adjustable high temp heated filter and vegoil temp booster. Unlike nearly all other "heated" filters designed to warm diesel to above gelling temps this one is designed for vegoil and does a much better job...despite costing significantly less.

Don't want to get too commercial here.
Contact me directly if you want more info.

Dana
danalinscott@yahoo.com