Veg oil, bad idea in a Pug106 D, KABOOM!!!!!
Discussion
Yep, I was smugly driving (on a private road) and it cut out totally, just like that. It was cold and I was raking the shit out of it. I have a feeling that the injector pump drive shaft has sheared. There was no noise of failure it just cut. I thought the cambelt may have gone (in a subtle kind of way) but a brief check revealed that the belt was fine. Discussed the high viscosity/blown seal thing but it would have stuttered. No stuttering or even bumpstart attempt at 5000rpm helped.
Autopsy tomorrow. I had thinned it to the required viscosity as well..
Autopsy tomorrow. I had thinned it to the required viscosity as well..
been following this one with interest.... it'd be interesting to find out what failed and whether it's something that can be prevented by a simple uprated part.
If it's an increase in load on the fuel pumps due to increased pressure from higher viscosity (or the difference in viscosity between oil in the tank and oil at the business end), then perhaps an uprated fuel pump? Or even simpler, fatter pipes.
Would you need to modify the injectors to allow the same flow and atomisation characteristics given a change in viscosity? Or is viscosity not a factor for misting injectors??
If the fuel supply pipes are clagged up with gunk then it's either reactions between the veg oil and the pipe material, the veg oil and existing diesel residue (modern pump diesel contains detergents, etc, right?), or the mix of chems you used to 'thin' down the veg oil in the first place.
The Pug 106 diesel is a pretty boggo old-fashioned motor isn't it? No fancy mega pressure electronically controlled common rail stuff? Should be 'convertable' unless there's one crucial behaviour that diesel has over veg oil... perhaps effective upper cylinder lubrication?
And are you sure you filtered the chips out of your veg oil before pouring it into the tank
A fat chippy chip should be able to block most fuel lines 
If it's an increase in load on the fuel pumps due to increased pressure from higher viscosity (or the difference in viscosity between oil in the tank and oil at the business end), then perhaps an uprated fuel pump? Or even simpler, fatter pipes.
Would you need to modify the injectors to allow the same flow and atomisation characteristics given a change in viscosity? Or is viscosity not a factor for misting injectors??
If the fuel supply pipes are clagged up with gunk then it's either reactions between the veg oil and the pipe material, the veg oil and existing diesel residue (modern pump diesel contains detergents, etc, right?), or the mix of chems you used to 'thin' down the veg oil in the first place.
The Pug 106 diesel is a pretty boggo old-fashioned motor isn't it? No fancy mega pressure electronically controlled common rail stuff? Should be 'convertable' unless there's one crucial behaviour that diesel has over veg oil... perhaps effective upper cylinder lubrication?
And are you sure you filtered the chips out of your veg oil before pouring it into the tank
A fat chippy chip should be able to block most fuel lines 
Silly idea - if the fuel system doesn't like veg oil below a certain viscosity (due to temperature variances) then perhaps put a big-ass fuel pump in the tank that can cope with really thick stuff, then run the output pipes through a thermostatically controlled heater before they hit the high-pressure and injection stages.
On a budget, I guess you could just run the pipes around a water hose exiting the block, keep the veg oil at engine water temp (around 80˚C?) should be spot-on for diesel-like viscosity and combustion.
Doesn't solve the potential loss of upper cylinder lubrication though. I am guessing here, but I presume that vegetable / bio-produced oils are not good lubricants as I have never seen them sold: all mineral oil products must be better and cheaper. Back to 2-stroke again with some special stuff in the fuel?
On a budget, I guess you could just run the pipes around a water hose exiting the block, keep the veg oil at engine water temp (around 80˚C?) should be spot-on for diesel-like viscosity and combustion.
Doesn't solve the potential loss of upper cylinder lubrication though. I am guessing here, but I presume that vegetable / bio-produced oils are not good lubricants as I have never seen them sold: all mineral oil products must be better and cheaper. Back to 2-stroke again with some special stuff in the fuel?
My morale has taken a big dive, it's cold and I haven't really been bothered to go and take it to bits. A quick test showed that fuel is getting to the injector pump (clear lines).
The opinions of the chaps over a pint last night was that the cold hair had caused the increase in viscosity, (I think it is more of an tangential rise than normal "parrafin" oil) me leathering the tits out of it caused the input shaft to shear.
This is a common problem. I'm surprised they didn't put a shear pin in or over spec the shaft
Edit, the pump isn't driving a resistance, the fuelling is fine, stop solenoid works, etc.
It is basically shagged. A new pump is £35 and so I am going to do to some viscometry experiments for various mixes of veg oil/kerosene and see which one is the goer.
>> Edited by love machine on Monday 24th January 15:53
The opinions of the chaps over a pint last night was that the cold hair had caused the increase in viscosity, (I think it is more of an tangential rise than normal "parrafin" oil) me leathering the tits out of it caused the input shaft to shear.
This is a common problem. I'm surprised they didn't put a shear pin in or over spec the shaft
Edit, the pump isn't driving a resistance, the fuelling is fine, stop solenoid works, etc.
It is basically shagged. A new pump is £35 and so I am going to do to some viscometry experiments for various mixes of veg oil/kerosene and see which one is the goer.
>> Edited by love machine on Monday 24th January 15:53
I've not followed the previous thread about your exploits, so i'm not up on your mixture.
What do you add to the veg oil to maintain the lubricating chracteristics?
I'd be real interested to hear which bit has broken although i'd suspect that the main drive shaft within the pump has sheared as a result of a sheared transfer pump.
What do you add to the veg oil to maintain the lubricating chracteristics?
I'd be real interested to hear which bit has broken although i'd suspect that the main drive shaft within the pump has sheared as a result of a sheared transfer pump.
Pigeon said:
I am guessing here, but I presume that vegetable / bio-produced oils are not good lubricants as I have never seen them sold: all mineral oil products must be better and cheaper.
Disproof by counterexample: Castrol R. See one of opieoilman's threads for the reasons.
Yep, think about margarine based cutting fluids, most cutting oils are veg oils with added turpentine to thin them a tad.
Castrol R is great stuff. Smells ansom, if I wore cologne, it would smell of Castrol R
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