Over-blending

[Jens]

Just a quick note about the possible issues/problems with blending.
Way back when, I attempted to blend some RUG in with my WVO. This resulted in some bubbles in the fuel line which I couldn't quite figure out where/how they were coming about. I eventually decided that they must be created because of the volatility of the RUG and I had blended too much.
Fast forward to today ....
I am trying to clear out my stock of mystery oil so I have switched from WVO to the mystery stuff which is a combo of WVO, kerosine/paint thinner, WMO and a small percentage of other stuff. Today I had a LOT of problems with bubbles. I thought that maybe the fuel filter was plugged but after replacement I had as many bubbles as before. I finally added some WVO and circulated everything to mix it up and it appears that almost all bubbles are gone. It looks like I will still need to add a bit more WVO but I have to run down the day tank a bit before I can do that.
Anyway, the moral of the story is don't over-do it.
I am still a bit unsure of it all but I will put the old fuel filter back in and will verify that everything is still fine with the higher percentage of WVO.

[Ronmar]

Are you heating the blended fuel?

[Lloyd]

Jens,

make sure the suction side of your plumbing is lower than you output side.

I had a very similar problem on my BW tranies...a mechanic hooked the suction out of the tranny to the sea water heatX, which is at a slight tilt up, but he hooked it to the up hill side, and then hooked the down hill side to the other end...

And I had a continued leaking of ATF...I replaced gaskets, seals nothing seemed to stop it...then one day I was reading the BW manual, and it had a note: make sure in-put is lower then out-put on the seacooler... What I found out is being hooked up wrong, it was causing the ATF to foam and come out the breather of the tranny. Now mind you the seacooler is at about a 3 degrees rise.

Check your plumbing make sure you don't have any low spots on the P side.

lloyd

[Lloyd]

Hi Jens,

i didn't even consider that it was a gravity fed...just make sure it's a straight fall no ups and downs..other wise it could be trapping air, and the turbulence is creating back eddys that multiply the bubbles.

You know after I posted it dawned on me that the perkins oil cooler might make a good oil heater if you plumb it in
http://www.tadiesels.com/oil-coolers.html
the HW side of your cooling sys. so instead of a cooler it's a heater.

lloyd

[Shipo]

LLoyd,


  Thanks for this excellent idea and tips on this part  to use it as a wvo heater....I will call to find out if it work with the pressure of the radiator hose to installed in-line... 

[mike90045]

Leave it to someone here to get vapor lock in a diesel.   

[vdubnut62]

Well, I feel better now. I know that I ain't the only one that  has weird stuff sitting around that I want to feed to an engine.
Ron

[Lloyd]

LLoyd,


 Thanks for this excellent idea and tips on this part  to use it as a wvo heater....I will call to find out if it work with the pressure of the radiator hose to installed in-line...  

Shipo,

It will work at radiator pressure no worries...my boat was originally set up with two on the radiator side for 20 + years. On top of that, in the Perkins install the top side is engine oil @50 psi and  180F oil temp, the bottom side is ATF @180 psi @ 260F.

When I rebuilt the engines, I put them back on the sea water side...as the factory...more cooling.

Also the unit are rolled tube copper-nickel..so they are very corrosion proof.

Lloyd

[bschwartz]

I too experienced bubbling with too much RUG mixed in my WVO powered mercedes.  Even unheated, the warm engine compartment caused issues.

[akghound]

It's confirmed - installed the old filter and all is well. The problem was too high a percentage of volatiles.

Jens

Any "Off The Top Of The Head" idea what would be too high a percentage of volatiles?  I'm guessing at around 15-20% if using RUG.
What do you think?
Ken Gardner

[rl71459]

Hi Everyone

I have a question... How is it that rug can cause bubbles when "Over Blended"? It does'nt bubble when used straight in a gas engine... I have never had a problem with this with my blending Waste Petroleum
Oil... Is it that the Veg has a problem with the rug?

I know that those who "know why" may be frustrated with those (Myself) who "dont" this is not an attempt to challenge what others have observed... I would just like to understand.

Thank You
Rob

[Crofter]

It can bubble in a gas engine. It used to commonly cause vapor lock back in the days before fuel injeciton.  Vapor point for gasoline can be in the range of 110 to 140 F. depending on seasonal adjustment blending. That is not hard to reach. This is at atmospheric pressure. If a vacuum is happening because of filter restriction in a gravity system the lower pressure reduces the vapor point even below what it is at full atmospheric pressure. The effects of system pressure or vacuum can be quite dramatic

The boiling point of diesel is over 300F and vegetable oil around 450F
I dont think mixing gasoline with diesel will yield a vapor point that is a simple average of each ones separate vapor point. In other words the lower boiling one will start to gas off a bit when it gets much above a temperature and pressure level where it would if it were alone. The more it is diluted volume wise though the more the vapor point will swing to the higher temperature.

Mixing petroleum gasoline with a different family of oil like WVO might not have even as much averaging effect as mixing it with diesel or Waste mineral oil.

[Geno]

Crofter, Your statement agrees with what I've seen in my system. With ~10% rug ~90% wvo my engine will sometimes slow down for a second, just like it was passing gas (pun intended) However it is inconsistent tank to tank. It doesn't happen in cold weather. I only heat the IP HP line. Injector temp is 190-210F

My post centrifuge filter is a gravity fed Frantz TP filter with a 125 watt heat lamp under it. With almost any amount of rug in this non-pressurized setup I get bubbles in the Frantz output line.

My issues are minimal and don't cause problems with normal operations of my setup.

Thanks, Geno

[Tom Reed]

I've seen my engine do this with RUG blends too.

[vdubnut62]

Wonder how much the 10% or so of  ethanol that's now in RUG is affecting things?
Ron