I have read that bio diesel fuel is not recommended for older diesels. This is all you can find in many places. Anyone know know what damage it can cause to our older diesels?

I was researching fuel additives on the internet and came across this independent lab in Texas that did a test on several of the additives on the market today including two cycle oil and bio-diesel. They tested for lubricty, cetane improvement and emulsifier.

They claim that all diesels are affected by the new low sulfur fuel standard the the government mandated. They also stated that the big oil companies claim they have the proper additives in place to restore the lost lubricty in the new low sulfur fuels. However most diesel owners are highly concerned about the new standards and are looking for additives to restore the lubricity.

The test results were quite interesting with the soy bio-diesel having the highest rating for lubricty and cetane, followed by opti-lube placing second and then the others. The additive I was going to use (Lucus fuel additive) was one of the worst it actually had a negative score.

They say bio-diesel fuels can be a great alternative to high sulfur fuel however they also say there's not going to be a future in bio-fuel.

One question I have is diesel fuel formulated any different at the truck stop lanes than the diesel fuel in the car lanes? I was talking to a couple truckers and they told me to make sure I fuel up with the big rigs. They claimed their fuel had the older formula with higher sulfur ratings.

Can't believe there is much economy in ordering,tanking two different types of diesel. Remember the old joke about truckers and cowboys and boots? But ya jest never know.

quote:

I was talking to a couple truckers and they told me to make sure I fuel up with the big rigs. They claimed their fuel had the older formula with higher sulfur ratings.

Some do have the LSD, but most are ULSD. I use 2-cycle motor oil as an additive.

Rusty
How much 2 cycle motor oil would you add to a 100 gallon tank?

8 oz/30 gal.

Is it ok to overfill a 100 gallon tank
with the 2 cycle motor oil
or should it be an exact ratio?

2-cycle oil is pretty much benign, since it's designed to be combusted. But there's no reason to overdo it. No more than a quart for a complete 100 gal fill up is plenty.

The addition is only to supplement the lube additives supposedly in ULSD.

Rusty,

What 2-cycle oil do you favor? I'm sure you did some kind of study on it.

Is STP too thick? It sure does lub.


Jim

Since all trucks 2007 and newer only can use ULSD all truck diesel is ULSD (see sticker on pump). Pump at truck islands be aware they are high volume and you might be getting backsplash with a RV. Using truck stops for diesel gets you usually a blend for the summer or winter and "fresh" fuel (less contamination due storage i.e. Algae or condensation). Fuel during cooler times. Use a good additive to replace sulphur (FTTP, Howes, Power Service).
The only issue with new or Bio diesel was that the fuel pump went out, it has a cleaning action that gets seals. No problems otherwise.
A good additive also prevents algae in your tank when stored.

quote:

Originally posted by Jim & Barb:
Rusty,

What 2-cycle oil do you favor? I'm sure you did some kind of study on it.

Is STP too thick? It sure does lub.


Jim

STP is crap. It is/was one of the most damaging products ever marketed (Is that enough info?) It isn't formulated to be combusted.

Remember back in the 80's when engine manufacturers specifically warned AGAINST using 10W-40 oils, especially in stationary and air cooled engines? (Actually, my GM manual for the 454 in 86Barth says the same thing.)

The multi-vis oils of the day were formulated to resist thinning at higher temps. One of the additives in 10W-40 was the same as the stuff STP was made of. While it did improve viscosity and started out very slippery, the stuff degraded fairly quickly and worse yet the products of degradation were abrasive and caused accelerated wear! (Great for a quick race but terrible for long haul.)

Lubricity is related to many factors but one of the main ones is molecular chain length. The compound in STP was not "shear stable" ie the long chains broke into pieces during use. Worse yet, the chain fragments caused extra wear. (These additives were long ago retired by the oil makers, the 10W-40 caveat no longer applies)

The advertising of the day sold a bunch of this crap, touting the "racer's edge." Maybe so but it was junk for daily drivers.

Rusty can supply more details I'm sure.

Author name deleted, to protect the innocent:

quote:

Some do have the LSD

It seems like an appropriate time to link to this, again: http://roadtrip.burningman.com...ent/silverseed.html#

If you ask me, though, healthy foods are the way to be going.
Matt

quote:

Originally posted by Kevin:

quote:

Originally posted by Rusty:
STP is crap. It is/was one of the most damaging products ever marketed (Is that enough info?) It isn't formulated to be combusted.

Rusty damaging crap is not really enough information for me. I have relied on it as an assembly lube product since I built bicycles as a teenager. I do agree that is does not burn or combust well. Is there an old topic that we have discussed oil additives (not fuel additives) or could you start a new oil additive discussion? Your point of view is well respected here.

STP is a blend of polyisobutylene and a napthenic base stock. It was one of the first viscosity index improvers (VIIs). At room temperatures, the polyisobutylene stayed coiled up and performed like a small molecule (low viscosity). At operating temps, it stretched out and preformed like a large molecule (high viscosity). The problem was that the stretched-out molecules mechanically sheared. This had two unfortunate effects. First, the oil was now at a much lower viscosity. Second, the sheared remnants tended to form hard, gritty deposits in the ring belt and valves.

STP is a very useful product for pre-coating bearings and journals before assembly.

Contemporary multi-vis oils have shear-stable VIIs, and they are recommended by most engine builders.

A 10W40 oil is an SAE 10W to which VIIs are added. The oil doesn't get more viscous as it warms up. It thins out less. So at the low qualifying temp, it's 10W; at the high qualifying temp it's equivalent to an SAE 40.