Adding 2 stroke oil to diesel fuel 4

[PPilki]

Hi,
I seeking some factual info - good and bad - on the current trend thats sweeping across all the car user forums on the web - adding 2 stroke oil to diesel. I thought this Forum could add some reality to all the "its works for me" type of posts you read elsewhere (Google it, they are endless !).

Its the new snake oil - or is it ? I've actually tried it in my Nissan TD42 and it does seem to have an effect. The engine is quieter and pulls better. Although I've not proved the lower fuel consumption bit yet, its looking good, certainly not worse.

So whats going on ? Why does adding 2T oil to ULSD suddenly make the engine seem a different beast ? Why does no manufacturer recommend this ? Why does the current ULSD respond to this treatment when the fuel suppliers say the fuel already has lubricity alternatives to the sulphur thats been removed ? Surely if a simple mix of 2T solves problems we need some facts from the fuel makers as to whats wrong with the current ULSD blend ?

Answers guys, and sorry if its already been covered, post me the link, I searched but didn't find anything.

 

[PPilki]

and forgot to add, is there any possibility that using 2 stroke oil (1:200 ratio) will cause any damage ? The only thing I've see is not to use it with DPF set-ups.

 

[evelrod]

The only thing that I do with my '91 Cummins is to use a "diesel additive" with each fill up to add a bit more lubrication to the pump since we are now using a very low sulfur content fuel. I have a bunch of 2 cycle oil...guess I could try that. It's oil and not much different than the commercial additive...cheaper?

Don't know the exact mileage on my Dodge...Bought it new Feb. 1991 and the odometer "died" about ten years ago at 186,000...I checked the valve lash at 110,000 and change oil and fuel filters regularly. Runs just fine. Certainly has paid for itself!

Rod

 

[JSteve2]

I don't know whether it works or not. It's not being recommended by the manufacturer because an unapproved additive can put more sulfur in the fuel tank than is in all the fuel, might be illegal, and certainly the manufacturer did not certify the engine that way.

Unmodified oil can be 5,000 ppm sulfur or greater, which is 300 times more concentrated than the fuel. I doubt that 2 tablespoons of anything makes a difference though.

 

[PPilki]

Guys, I suggest you try it. I was very pleasently surprized on just how different the engine feels and drives, all on the face of it for the better.

The keys are: 1:200 ratio. Use a mineral based 2T as sold for saws/mowers (cheaper the better !) etc and not the boat outboard motor stuff and not synthetic. Don't use it in engines built in / after 2007, althought this is up for debate as users with CRD motors are reporting benefits. I think the key there is not to use it if there is a DPF.

Cheers
Phil

 

[ivymike]

I don't know offhand what's actually going on, but your description that the engine "feels and sounds" better says to me that you're likely affecting the rate of pressure rise in-cylinder. Additional lubricity would not, in my opinion, make an externally-discernable difference.

That said, I'm not sure what would account for a change in the rate of pressure rise given what you've said you've done to the fuel. Things which might be involved:
- change in fuel viscosity and therefore amount delivered, spray pattern, and droplet size
- change in combustion characteristics of fuel (ignitability, injection-combustion delay, etc)
- quantity of energy released (but how much difference could 0.5% make?)

 

[ivymike]

1:200 ratio doesn't seem typical online. An example from another forum: "I use a mix of 1 quart 2-stroke oil, and 1 quart of Power Service Diesel Kleen per tank of fuel - EVERY fillup!"

I don't know how big his tank is, but I suspect it's less than 200qts (probably more like 80qts).

 

[BrianPetersen]

A diesel engine will run on a remarkably wide range of fuels, but that doesn't necessarily mean it's a good idea for emissions, durability of seals, etc. If you can make them run on waste vegetable oil (for a while) you can make them run on straight motor oil ...

Using an excessive amount of 2-stroke oil probably won't damage anything on an older non-emission-controlled diesel with no catalytic converter. But I doubt if it will do much good, either.

 

[SomptingGuy]

Sounding better could be due to heat release shaping.
Feeling better is probably subjective, based on the above.

Adding unspecified cack to fuel may or may not improve the lubricity of the fuel, but pumps and injectors generally outlive engines. anyway.

I always used to pee into my compost heap.

- Steve

 

[ivymike]

you can make them run on straight motor oil
there are kits for large trucks (mining, etc) that cause the engine to consume a controlled amount of its own oil along with the fuel, so that clean oil can be continuously added and oil changes avoided.

 

[patprimmer]

A major oil leak into the cylinders on a diesel can actually cause a runaway engine.

The two stroke oil is formulated to lubricate when mixed with fuel and to burn with it. The combustion products do no harm to 2 strokes. It could be safely assumed that no damage would occur to a diesel where components are similar. Exhaust emission controls on modern diesels will be different to the exhaust components on a 2 stroke.

In my opinion (without supporting data) the 2 stroke oil will burn as fuel. It may very very slightly add to lubricating properties of the fuel and maybe benefit the fuel pump/injector but almost certainly not to a detectable nor measurable degree.

At 200:1 its effect on burn rate, fuel viscosity and energy content should be unmeasurable.

Any change to perceived performance will be due to placebo effect.



Regards
Pat
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[drwebb]

"Use a mineral based 2T as sold for saws/mowers (cheaper the better !) etc and not the boat outboard motor stuff and not synthetic."

Well cheaper means more brightstock and less/no polybutene (no smoke), and maybe less dispersant. High molecular-weight polybutenes have been used as anti-misting aids, perhaps arguing against a droplet size effect. Not outboard means that anti-corrosives spoil the effect, which suggests a surface activity effect, but 'not synthetic' seems to exclude ester stocks, which should be more surface active than brightstock.

One may conclude the anecdotally based recommendations seem to be pointing in conflicting directions as to what the active ingredient may be . . .

How might 2T oil affect cetane rating?

 

[PPilki]

In one post I found this.

Use 2stroke oil with the following spec:
Low ash < 0.05%
JASO FB/C ISO L-E GC or GD
Dont use fully synthetic
Outboard stuff was a no-no in the European posts, but in the American posts it seems to be OK !

I must admit to not knowing anything about 2 stoke oil specs and there may be typos in the above. There was mention of Mercedes having done some work on this, andI think the above specs may be from that work - dunno ?

 

[LadaTrouble]

I had a case of unwanted 2 stroke oil to use up,and put a litre in every full tank of my 4D56 powered Pajero.I noticed no difference in anything.Although when I sent my injector pump in for overhaul at 300,000km ''just because'' - they said it was in perfect condition and didn't really need a service....just new seals and calibration.

 

[patprimmer]

I take it your Pajero was pre current pollution laws for diesels.



Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[JSteve2]

The "2T oil" was the type, not the quantity.

You should absolutely never do this in an engine designed for ULSD. At the 200:1 ratio, your catalyst could be seeing 2.5 units of sulfur for every designed 1 unit of sulfur, turning your 250,000 mile catalyst into a 100,000 mile catalyst, voiding warranties, and opening yourself up to other trouble. At a more realistic 50:1 (or other similar 2-stroke type ratio) your catalyst could now be seeing 7 units of sulfur for every designed 1 unit of sulfur, turning your 250,000 mile catalyst into a 36,000 mile catalyst. With one good high-sulfur slug (say you add too much with a low fuel tank) and you can actually brick your catalyst within a few hundred miles (it's at least partially recoverable but the controls won't recover it because they won't know what happened).

 

[bluebeast]

Old timers used to change the oil in their semis and then dump that ten gallons of used oil straight into their fuel tanks, Sure there is always metal particles but that is what fuel filters are for and Many a truck went hundreds of thousands of miles doing that. Now to today. My buddy worked for a company doing deliveries with isuzu box trucks and he filled one up once with 87 octane gas of course he got in trouble! Well one day he calls me, Man this truck is losing power! It won't barely get to 45mph!! I said you filled up with gasoline again didn't you? He thought for a second and looked at the fuel reciept and yep More than a half tank of 87 octane! I told him to hurry up and get off the highway and find a dollar store. I had him buy a like 4 quarts of motor oil and dump it in. He said it started running better but it was still popping and barely accelerating, So I had him pick up some more. I forget how many quarts he eventually used but it was all the money he had. The truck actually ran better than ever he said and noone at the company was the wiser. I don't recommend using gass and oil mix but a diesel will run on a wide range of fuel and as long as you don't have a particulate filter adding some motor oil won't hurt anything two stroke or crankcase oil!

 

[LadaTrouble]

[I take it your Pajero was pre current pollution laws for diesels.]

We have no pollution laws in New Zealand - EGR's are plugged,and cats cut off.

 

[JWaterstreet]

I agree with Patprimmer; this is just placebo effect. Witness the thousands of satisfied users of those $19.95 magnets placed over the fuel line to "align" the fuel molecules. I never trust anyone that says their engine "runs better", because it is almost never true....

 

[ivymike]

that may be, but I've also found that people who are familiar with engines are quite good at hearing and identifying changes in the sound of those engines... much better than a lab guy with a herd of accelerometers.