The Mitsubishi Pajero Owners Club®

[shaunlfc1]

Hi all,

I've just started running my truck 2.8TD 1994 Mk2 back on veggie oil, i've installed some injector line heaters and a fuel filter heater to help it run on 100% Veg oil.

BUT my friend who knows engines very well reckons Jap engines have rubber piston rings and other rubber components that the veg oil will destroy and cause exhaust gas to be blown back into the engine, and a simple check is too run engine and take oil filler cap off and if there's alot of gas or blowing with alot of oil spitting out this is a major problem.

This is what I have, in my eyes the engine sounds and runs the same, but apparently I need to rebuild the engine with new rings ( well the rubber ones anyway) can someone help confirm this?

Many thanks,

[Google]

[vmaxsnoopy]

There certainly aint any "rubber" piston rings to worry about mate. The only issue you may find with your 4M40 motor is possible problems with the internal seals in the fuel injection pump. This is by no means gauranteed to occur though, and plenty of members run trouble free on mixed and / or SVO.

[shaunlfc1]

So what is causing the exhaust gas blowing back in causing the oil spitting from filler cap? My fuel pump seals where done 18months ago, so would the new seals be able to take the SVO?

My mate says Jap engines have certain rubber components that will degrade from the veg oil and his Surf blew up when he was running it on veg oil because of the degradation.

Thanks for the help.... a worried Paj owner

Shaun

[vmaxsnoopy]

If you have crankcase compression then you have piston ring/bore wear. However, this is extremely unlikely to have been caused by running on veg oil. What can occur on the 4M40 engine is dilution of the oil in the sump with diesel (or veg oil) when the bottom seal fails in the fuel injection pump. This usually shows up as the oil level increasing in the sump as the diesel or veg oil leaks in. This diluted oil can accelerate bore wear through inadequate lubrication. The only "rubber" components that can be affected by using Veg oil are the fuel pipes themselves, and the seals in the injection pump. With the filler cap off you will get spitting from the motion of the camshaft. Is there any smoke ? does the engine use any oil?

[shaunlfc1]

Ok this is sounding more promising..... The truck was serviced very very religious by the previous owner and I do all my own servicing, and she is very smooth, "no trouble" engine. She does us a little oil but nothing at all serious in my eyes, doesnt smoke badly at any time, and still feels as smooth and strong as when I first brought her.

When we opened filler cap last night there did seem to be some sort of gas/smoke coming out filler hole but nothing I would say i've not seen before since owning her for 2 years.....

Thanks for help smiling a bit more now....

Regards........

[leeandeb]

run my delica 4m40  (2.8 td ) the whole time i had it on veg oil with no problems.
@ what % i have no idea just kept pooring veg in until it was a *beep* to start then put in some petrol/dino mix and carried on.
that inpressed with the trucks when i sold my deli i bought a 2.5 pajero... yes veg is in there to...

[vmaxsnoopy]

When hot you will always see a bit of smoke when you remove the filler cap mate. If its running well otherwise, I would just tend to not worry too much.

[shaunlfc1]

I did loads of research on here and other websites about running veg before I did my small conversion, so I could run on 100% and it didnt turn up anything to look out for or any major problems which is why I took the plunge to do the small conversion (heaters). Its just my friend instantly said he felt it sounded more agricultural then it did last time he was in it which was March this year. The large spitting of oil and smoke/gas coming out of the filler cap is exhaust fumes blowing back in due to piston ring degradation through veg oil use, which too me is nothing out of the ordinary but is exactly what happened to his Toyota Surf, before it finally blew up whilst running on veg oil....

Thanks for ya help.... I little less worried....

Would the fuel pump have seals in it now that should be fine with veggie oil? Would it only be the original Jap seals that would be affected by the veg? As I said it has had the seals replaced 18 months ago and there is no sign of the oil level rising in the sump?

Thanks again.....

[Richie]

If your running 100% or very high veg oil, thenyou will get a build up of gunge, you have no detergent in your fuel, like pump diesel, to break this away, so, so injector cleaner every so often, or even straight derv when you can.

Rubber, pass  

[prhodesj]

just out of interest...... if the seals did go in the fuel pump, how much would it cost to repair, and how much are the seals. also is it a job you could do yourself to save money

[offroaddriver]

my old 2.5lwb did over 60,000 on 100% veg. never ever gave me a problem.

infact, it did so well, when the vehicle was scrapped, skymatty took the engine out and he is now running about with it in his truck.

so in answer to your question, veg oil certainly wont kill it.

tom

[dannyrsturbo]

my head gasket went a year ago ..and some complete idiot had it stripped down outside his garage for 7 months untill i dont the work myself ..im by no means a mechanic and the he stood around and advised me on what to do ..   its pressurising in the head with oil coming out from under the cap and blowing white smoke,missing a little   and ive just put a new gaskett on and a brand new head ...i turned of ignition earlier and it started to rev up instead of turn of then it spluttered and died   it runs almost fine ,it was knocking but i bought second hand injectors of ebay and it sorted that out..   why did it rev on its own ..     ive spent so much money on this car im gutted ..maybe the idiot didnt torq the headbolts down or something ..new gasket new head ..  ;((   god knows ..should i take the head off and put it back on again..

[trekker]

Your last description is that of the crank case not venting enough gas and consequently building up pressure in the crank case and rocker cover.

This will cause many oil leaks, and even running on and over revving.

The place to start is the rocker cover. Remove this, invert it, fill it with engine cleaner and swish this cleaner to and fro to flush the filter / labyrinth which separates oil from the mist which should exhaust through the crank case breather. Blow back through the breather pipe, drain this engine cleaner and repeat this cleaning flushing process. This took me a few hours, soaking over night would improve the flush.

Finally flush again with hot water, shake it dry and refit.

That should overcome the pressure build up and the oil leaks, depending upon the piston ring wear.