2-stroke in diesel a myth??

Hi Bruce

I once had a diesel injector place suggest that some unleaded petrol now and then in the diesel would 'clean out the system'.

I tried it with my old HJ75.Well it certainly improved the power. Went much better.

Unfortunately I burnt out 2 glow plugs. I thought that might be just a coincidence so some 6 months later I tried it again. Burnt out another glow plug.

I think adding even 1 litre to a full tank of diesel is just too much. I think the fuel burn was too hot and heavens knows what else happened inside the combustion chamber.

I stopped doing it.

David

I used to put 300ml of unleaded per tank (90lt) every second fill in all my 2H and 1HZ motors and they were smoother and quieter and had more power.
Never had any glow plug issues and I was living above the snow line at the time.
The biggest cause of premature glow plug failure is not letting them glow right up.
The landcruisers have a dual system, 1 for the light and 1 for the plugs.
If you turn on the ignition ignore the light, watch the volt gauge and listen for the click. Only after the click turn the motor over. If you go only by the light they will only half glow.
The plugs also stay on for around another 30 secs after starting at a reduced voltage (the click when the gauge comes up slightly).

The other thing is it is best to replace all the glow plugs at the same time don't mix and match.

Cheers
Dave

Hi Allan, did the person on that other forum mention anything about people gathering around his exhaust pipe, LOL.

Interestingly, where I work we get through some cooking oil in the deep fryer and it is changed very regularly. My neighbor asked for a drum and so I gave him one and he filtered it out and was putting into his Massey Ferguson tractor. he said it made the world of difference to the sound of the motor. Made it run much quiete. I was convinced enough to add some to my tractor and was amazed at the difference. It immediately ran much quieter. That is why I was not suspicious when others said that oil in the diesel would lessen the wear factor.

Our mix rate was around 1 litre cooking oil to around 50 liters of diesel.
These machines will run on straight cooking oil though I am not advocating that.
Regards, Bruce

Hi Bruce,

I note that a number of people have commented on quieter running. Is it possible that the combustion reaction rate is changed and thus reduces knocking which is the cause of most noise of a diesel engine?

I'm inclined to agree; the burn rate is probably changed. But as I understand it, the very fast burn rate of diesel in an engine is part of the reason for its high thermodynamic efficiency. Could this mean that the efficiency is reduced when the knock is reduced?
Re additional lubrication, diesel is itself a lubricant, and injector pumps would be designed around that fact. Rotary pumps, anyway, dunno what the new CRD pumps do...

Agree with Allan B above

goes to the principle of heavy versus light oil (read fuel) and burn rate and revs

older diesels that ran on "gunk" years ago would strain under cylinder pressures with todyas diesel IMHO

hi all
last week after being so happy with the lower noise factor in my vw golf crd1.9diesel and smoothness
i decided to add 2st to my mazda bravo 1997 diesel and after only 100km's the has transpired it into a very quiet and smooth motor on start up and under harsh throttle cruising along it's hard to hear any diesel noise at all and it's not my imagination it's a fact

i have thought about this a lot and although i have no scientific facts imho i believe that the two stroke softens the detonation of the diesel in the cylinders hence the much quieter motor but i have also noted there is no reduction in power in my vehicle as was suggested by someone that this could happen
no one has forced me to add the 2st oil but im quiet happy with the notible results so far on both vehicles
so if you dont agree or want to follow suite well so be it as it's upto the individual owners
but i dont believe it's a mythe as one experienced diesel repairman stated as it's his own text book trained opinion and some one at some stage will break ranks and try something new
is'nt that how new systems are developed after all

but there is enough forum evidence out there and some with thousands of km;s of 2st usuage with no ill effects but then after all that's mho and everyman to his own liking
cheers and for what it's worth

QUOTE. Here we are in the year 2010 with Biodiesel ~ and vegetable oils and used " Chip shop oil " successfully running modern diesel engines....

No NO NO. Not in modern CDI Engines you don't. When the system comes to a grinding Holt, and it will, the manufacture will politely tell you to bugger off.

The old inline and rotary pumps are fine they will chew up anything.

Cheers
Wayne B

Seems somewhat odd that Ruston has been making diesels for donkeys years and only just started putting 2 stroke into them to cure the "valve problem"?
What was the cure previously?

Quote: "What was the cure previously?"

Answer: Probably 5000ppm sulphur content in the diesel. It is this lower sulphur content in diesel (50ppm now a days), that is causing issues with older diesel engines from what I have read. This was certainly the "cure" on my old fashioned Chev 6.5 V8.

Of course, it goes without saying (but I'll say it anyway) that the fuel companies will swear on a stack of bibles that their low-sulphur stuff won't hurt an engine........but then again, of course they'd say that, wouldn't they. Imagine the ramifications if they agreed that their crraappy product was causing expensive machines to fail or at least operate in a less-than-ideal manner.

Roachie

Not odd at all, they moved into the next century, and this was a new high out put low weight diesel a few years back.

Note! 40lb boost on turbo and peanut cams as used in racing engines, high lift/long duration and slam shut very quickly.

Roachie (and others), it's not the low sulphur content of the diesel that affects the lubrication. The problem is brought about during refining where removing the sulphur also causes removal of other components that provide lubrication. This is then addressed at the refinery by adding suitable lubricants.

Thanks Allan for that insight...... I wasn't sure "why" it happened....just aware that it "has" happened.

As I said in an earlier response..... I don't know if there's any scientific evidence about the benefits of adding 2 stroke to my diesel tanks, but it runs that much smoother that I will continue to use it.

Before i started using it, I honestly used to whince everytime I started the cold motor. It sounded like all the rockers were unbolted or something....banged and rattled terribly. It was okay after about 1 minute of idling.

Now, with the 2 stroke, it sounds okay right from the get-go. Also, whilst I don't expect it has anything to do with me using the 2 stroke, I have also noticed recently that oil pressure is present within 2 seconds of starting the engine....used to be about 5 seconds.

Roachie

all be it marine 2 stroke oil

Howesy,

thanks for that, it is a very thorough test.

Have a good one

Ah, Phil, you're just thinking back to the old days when you added a banana to your diff or gearbox before selling it, to quieten it down a bit...hahahaha

John,
My background is 40 years as a Research Chemist in the oil industry.
Some of the comments above are not well informed including those from people claimining some association with the Refining of crude.

The issue you mention concerning leaking seals after the introduction of Low Sulphur distillate was caused by the Refining process removing an increased proportion of Naphthenic and Aromatic components from the end product along with the sulphur.
The lower level of these Aromatics/Naphthenics reminining in the fuel allowed the seals to shrink reducing the interference fit thus allowing leakage.

The oil companies responded by adding seal swell additive to the fuel.

The Sulphurised terpenes and naphthenes that were removed during the desulphurising process were in fact the significant antiwear compounds in the higher sulphur fuel of past years. These compounds decomposed at the interfeace of metal to metal contact in the pump surfaces creating active sulphur compounds that bound to the metal {Iron} surface creating a sacrificial Iron Sulphide type layer that was worn away preferentially therby reducing the amount of metal removed during operation.

As an example the same process is at work in differential oils interaction with the gear teeth.

Two stroke oil particularly low ash Marine two stroke [TCW 3 spec] has some very good active antiwear compounds, not quite of the calibre of the Sulphurised compounds in fuel and gear oil but nonetheless they do reduce the wear rate in the pump.
The best products to use are specially formulated for the reduction of extreme pressure wear as in fuel pumps. Products like Opti-Lube and Flashlube are typical.

Thanks for that ranger,

useful to know.

I wonder how a very small quantity of gear oil well mixed with diesel would go. Gear oil of course has additives to counter extreme pressures generated in applications such as differentials. Don't know what other nasties it's got that may damage a fuel injection pump. Personally I don't think I would put anything other than straight diesel in modern CRD systems though.

Cheers Pop

Ranger, thank goodness that someone with appropriate expertise has contributed.
Perhaps you could be more specific about your expression that "Some of the comments above are not well informed"

Are you able to comment as to why the oil companies do not introduce components equivalent to Opti-lube and Flashlube to the diesel at the production stage?

Peter, I cannot see where Ranger said "make older diesels run more smoothly"

Sorry, that was my inference from improved lubricity.
However in my case at least, it does quieten down the injector pump and the engine is a little smoother - not that a 1HZ is rough/noisy in any case.
My Cruiser has done 407,000 km, still going strong and I'd like to keep it that way. It only costs me $2 per fill to add the 2-stroke oil and I think that's cheap insurance.
Cheers,
Peter.

Yes Peter, now that I have an opinion from an expert I think that I also will add TCW-3 to my 1HZ even though it's barely run-in at 250,000km! If I can locate them I may use Opti-lube or Flashlube as Ranger recommended but I bet they are more expensive than TCW-3.

Note however that Ranger only referred to reducing the wear rate in the pump, not the engine in general. Even so, prolonging the pump life could be a considerable saving.

For good measure I may even strap a magnet onto the fuel-line. LOL

Doug, here is a copy'n'paste from above....... (just for you). I can't make myself any clearer than this:

Well, I've been using 2 stroke in my 6.5 litre Chev V8 diesel for about 8 months now and it has DEFINITELY made it run quieter and smoother. I would not continue to spend the $$ on it if I had any doubt about this at all (cos I am a tight rrrrrr-s!!!! hehehe).

That's all the proof I need.

On a totally different tangent Doug , have you seen the photo of the croc shot a Boorolloola last week ,6.325m or in the old money 21 and a 1/2 foot long ,, i have trouble getting the photos up on here so if you want will email to you so you can post em up , bl----y one big lizard that chewed the prop of the boat !