Thoughts on fuel heating?

[EvergreenSD]

I wanted to see what you all thought about preheating fuel. I have seen various systems that other makes use to heat the fuel before it reaches the pump. There are filter housings heated by 12v or coolant as well as inline heaters of both kinds as well. Are there mileage or driveability benefits to be had here? It certainly couldn't hurt cold starts any. Is this something that would be a benefit only in cold weather or year round?

[philip]

SNIP There are filter housings heated by 12v or coolant as well as inline heaters of both kinds as well. Are there mileage or driveability benefits to be had here? It certainly couldn't hurt cold starts any.

What you think should be so ... may not be so.

When you have fuel with a fairly high cloud temperature, then you need to heat the fuel so that it passes through the filter media(s).

For cold starts on fuels that cloud at a fairly high temperature, you may need instant preheating on the lines feeding the injectors too.

Personally, my chosen path ('cuz snow is not a winter feature here),is to pretreat the fuel for trips to sub freezing areas. So far I've used only PowerService and Howes.

Al has quite a bit of qualified first hand experience with mixed fuels and biodiesel. Al ... where are you?

[asavage]

Philip, you disappoint me . . . you're the one with coils of fuel-containing copper tubing wound around your upper radiator hose:



Esplain to the man, Lucy!

[philip]

Philip, you disappoint me . . . you're the one with coils of fuel-containing copper tubing wound around your upper radiator hose

Yea Verily! But not since last summer. This homemade preheater does nothing for cold starts and when one LEAST needed warmed fuel, provided injection pump inlet fuel temperatures as high as 150 degrees.

Fuel economy suffered with rising fuel temps that were dissociated from high intake air temps.

[philip]

I wanted to see what you all thought about preheating fuel.

Our current southern California Indian Summer conditions not withstanding (temps in the 80s), are any of you experiencing fuel gelling or cold clogged filters, especially those using biodiesel?

Last summer I saw a homemade fuel warmer. It was a coil of copper tubing just like the one I made for the upper radiator hose but ... wrapped around the secondary filter. Still does nothing for cold start gelling. Seems any cold start aid is going to electric.

[asavage]

Seems any cold start aid is going to electric.

The Ford 6.9l and GM 6.2l both use electric elements wrapped around the lift pump line. The units are self-contained: they look like fat steel fuel lines with a jacket on them, and two wires/connector coming off one end. Their thermostat is integral.

Lift pump is before sec. fuel filter.

[EvergreenSD]

I currently have an approximate B50 blend in the truck and haven't had any gelling problems with lows into the high 30's. I still had B99 in the tank a couple of weeks ago when the lows started to drop into the low 20's. I didn't see any evidence of gelling then either (my primary filter is water-clear) but I ran out and topped off with #2 so I wouldn't learn the hard way.

So far I haven't had any issues with the B99 that I ran all summer long except for fuel lines which I expected. The lines have softened and I re-replaced a couple of them already (only because I had extra fuel line). Now that I am finally starting to have most of the problems weeded out I will be looking into a more permanent fuel line solution. The fuel injection line that was discussed on this board sounds promising. I will need to look into pricing and try to verify for myself that it is viton-lined.

I really haven't played with the fuel system any since I advanced the pump timing and essentially solved my problems. Now I expect maybe 5-10 seconds of roughness and mild smoking on a cold startup and I am good after that. I haven't driven very far during this time, either so I am eager to see what difference, if any, the timing change will make on fuel mileage.

[moose60]

Philip-
The gelling temp of biodiesel typically depends upon the oil source. I have started successfully on homemade bio down to about 22*F, with no real excitement. This was with a Mercedes 240D several years ago. However, biodiesel made from palm oil, or coconut oils tend to gel as high as 40-55*F!

I'm not seeing any evidence of gelling (local temps 37-55*F) with my current fuel which is about 25% commercial biodiesel (soy based) and 75% low-grade homebrew biodiesel (not my manufacture, WVO based). I say low-grade because several shortcuts were taken during the process and the resulting fuel is visibly of lower quality. Runs well though.

One of my projects this winter is to help the folks who made this biodiesel set up a good processor and create a set of instructions/guidelines for creating biodiesel which meets ASTM.

[dieselscout80]

I wanted to see what you all thought about preheating fuel. I have seen various systems that other makes use to heat the fuel before it reaches the pump. There are filter housings heated by 12v or coolant as well as inline heaters of both kinds as well. Are there mileage or driveability benefits to be had here? It certainly couldn't hurt cold starts any. Is this something that would be a benefit only in cold weather or year round?

Fuel heaters are not a starting aid. They are to keep fuel from gelling so it will pass through the filter (although getting fuel to the pump aids in starting ). They are low wattage and if IIRC, my Racor one is 200 watts or less and the 6.5TD ones are too.

The fuel you start with is in the steel injector lines and pump.

Carey

[Dave S]

Gentlemen-

We've been running B99 for about a year, both in my 82KC and the wife's 87TD Mercedes.

Have had no cold start problems with either, even when the bio in the 1" feed line to our dispensing pump was gelled up solid.

This has happened more than once, and the commercial B99 we have delivered to our 330 gal tote has always re-liquified when the temp came up.

Although some other local folks had problems with their bio from the same supplier, (I suspect water contamination in their tank) we have had no downtime.

I routinely use an "inline" block heater, makes the "crisp" early morning starts less rough.

I would like to install an actual in the freeze plug hole block heater, but have not determined if the block plug holes are the same size in the sd22 as in the sd25.

As posted elsewhere in this forum, the sd25 block heaters are still available from the dealer quite reasonably priced.

Dave

[Knucklehead]

Early one fall a few years ago I got caught in Albuquerque on about 50%WVO in a cold snap. Warm day, but a few hours later it was near freezing and the mix that usually worked was starting to clog the filter as the motor was running (been running all day). I was unprepared and couldn't buy anything anywhere. Took about 8 ft of bailing wire and wrapped it around the filter (12"x5"dia. big) and straight to the battery. Perfect! I'm guessing about 200 watts of heating. Made it through 100 miles of snow that night. Otherwise I might have been stuck there for a while if the motor had gotten cold. Foolishness.

[philip]

SNIP Warm day, but a few hours later it was near freezing and the mix that usually worked was starting to clog the filter as the motor was running (been running all day). I was unprepared and couldn't buy anything anywhere. SNIP

With that D2/WVO (50/50 mix), was there a reason stirring in some gasoline would have not worked as an anti-gell measure?

[philip]

SNIP
I routinely use an "inline" block heater, makes the "crisp" early morning starts less rough.

I would like to install an actual in the freeze plug hole block heater,... SNIP Dave

Getting the engine fired off is a matter of having fuel in the injectors and their feed lines that is "sprayable." So ... it appears keeping the cylinder head temperature above the fuel's gell point is the trick.

[Knucklehead]

With that D2/WVO (50/50 mix), was there a reason stirring in some gasoline would have not worked as an anti-gell measure?

I have not found a mix that would do the trick. With almost any WVO there are an array of different fatty acids with different melting points and densities. Although the fuels mix, they each retain their respective properties. Without continuous agitation the heavier parts begin to settle and regardless of agitation they will crystalize sooner.

I have some stuff from http://www.dieselsecret.com/ that is suppose to mix D1, gas, and WVO into a stable low viscosity compound. I have yet to fiddle with it.

[Dave S]

Gents-

I, too, bought a package from diesel secrets. When I discovered it was just another kerosene mixture plus their "secret" additive, I put it on the shelf. Haven't touched it since.

If their "blend" is now using gas, I'm even more skeptic.

I'm a firm believer in either bio, bio/D2 blend, or D2.

I'm not a fan of wvo/svo, and as Al has so succently pointed out, the possibility of damage outweighs the savings, at least for me.

I've a neighbor who runs a wvo setup on his MB wagon. In the last year, I've seen him replacing clogged filters on the side of the road three times. And those were just the times that I actually saw him.

He ALWAYS carries spares, only uses non-hydrogenated oil from a couple of semi local asian restaurants, ( a requirement with diesel secrets brew) and still, after letting his wvo settle for two weeks minimum, then filters it, gets stuck on the side of the road.

He also has a complete similar vintage Mercedes, non-runner, as a parts doner!

Given the vast savings he's accrued, I'm sure he's already paid for the $800-1000 conversion package, the trip to Cal to learn the install, plus a couple years worth of spare filters.

The b99 we get from Sequential is just fine with me. And if I'm away from home, well, D2 works just dandy to get me back to the barn.

OK, I'm done blathering

Dave