First test with the filtered WVO on the diesel bike

[alexanderfoti]

Hi all

I have an Kubota D950 IDI diesel powered Honda superdream (250, not really!).

I have been running it on diesel for the past 3000 miles or so, and it runs well. It has had a bit of a lazy cylinder, but when warm its not noticeable.

Anyway, chucked my wvo into it (5%petrol the rest 10 micron filtered wvo) and it ran ok, until I return to idle then it stalls.

anyway, long story short, one pot doesn't fire at idle with WVO, a small test tank confirms, pour in diesel, pot 1 comes alive, pour in WVO, pot 1 dies (cold downpipe).

It runs OK under load with WVO, but I still need to advance the timing, and obviously sort the issue with the non running cylinder.

Question is, is it likely to be the injector causing this, or the injection pump?

I'm thinking the injector, but cannot be sure... It runs a bosch style injection system, nearly identical to the Merc 300td (om 606) engine.

[Keef]

Can't you swap the injectors around to see if the misfire goes with it?

[Tony]

Yes I guess it depends on the cause of the "lazy cylinder" - injector spray pattern or low compression?

Maybe one for steam cleaning or water injection to help with? (Even if it's just manually squirting a bit of water in the intake when it's running higher RPM)

Very interesting project though, do keep us posted

[therecklessengineer]

I'd bet either injector or timing.

Swap them over - see the fault moves with the injector.

[greasemonkey]

When you say cold down pipe, do you mean the pipe to the miss firing injector is cold, while the others are warm?

That would suggest that fuel is not passing down the pipe, or at least not at the same rate as the others.

Could the pipe be semi blocked?
Lets more through on diesel, because it's less viscous, or it just runs better on diesel anyway?

I'd be inclined to pull the pipes off altogether, check for blockages, or dirt in the union of the dodgy injector. Maybe blow the pipes through and refit to the pump.
You could put the pipes into three different bottles, and turn the engine over by hand. It might give you an indication if there is a significant difference between the volume the pump is giving to each injector.

[K.H]

We need pictures! 

[Glycer-rides]

When you say cold down pipe, do you mean the pipe to the miss firing injector is cold, while the others are warm?

That would suggest that fuel is not passing down the pipe, or at least not at the same rate as the others.

Could the pipe be semi blocked?
Lets more through on diesel, because it's less viscous, or it just runs better on diesel anyway?

I'd be inclined to pull the pipes off altogether, check for blockages, or dirt in the union of the dodgy injector. Maybe blow the pipes through and refit to the pump.
You could put the pipes into three different bottles, and turn the engine over by hand. It might give you an indication if there is a significant difference between the volume the pump is giving to each injector.

I thought he was meaning the exhaust pipe from that cylinder.

[Glycer-rides]

We need pictures! 

Think there was one of the bike on the other side?

[greasemonkey]

Ah, yeah, the exhaust pipe. Makes more sense...........

[Chug]

I cant get the pictures on the other channel for some reason no matter what I try, but it looks like others have.

[alexanderfoti]

First off, pictures here as promised:




Second, had a bit of a play again, got it running on WVO and idling, but its not happy:

https://www.youtube.com/watch?v=pwu_NKPe0II

I swapped the injector from no 1 to no 3 and they now all fire..... annoyingly! I tried to check the spray pattern when the injector removed (running of the injector pump) they did not look great to be honest.

They did however look like the picture:



The uneven idling you hear on the video, it did that on diesel when its cold as well sometimes.

Lots of white smoke too, I am not sure how accurate the injection timing is, but its possible it needs to be advanced, and that it was always a little retarded, even for diesel.

[therecklessengineer]

Things that occur to me:

Timing
Nozzle spray pattern
Air in fuel

The last is probably the easiest to check - put an inline filter in the fuel return to tank. Check it's free of bubbles. With the thicker WVO I wonder if you need an external fuel pump to bump the pressure up a bit.

[alexanderfoti]

Thanks

Timing - I have had the same though, it seems as though it needs to be advanced. Cold starting is troublesome.

Nozzle spray pattern - I have no way of testing this per se. I will get them sent off to Diesel bob and cleaned/calibrated.

Air in fuel Another possibility, I have renewed all the pipework recently so that's all good. There is a mechanical lift pump that I am using, bolted onto the D850, Its a pretty stout little thing.

For the testing video, I am running with the return and supply submerged in a container of fuel.

Here is a cold start vid showing the rough running on diesel:

https://youtu.be/ySaid_YgsH4?t=22s

It was the coldest day of the year here, 6 deg c, notice when the afterglow stops, it does the same loping idle until it stalls.

When its hot it used to blow white smoke like this:

https://www.youtube.com/watch?v=tcuFeiDFrJM

[dgs]

Something like 10 years ago (before I started making bio) a friend went to bookers and bought 60 litres of svo which he duly poured into his tank. The engine would hardly produce any power. I helped him drain the tank and re fill with pump diesel. We drove it about 50 miles and the engine slowly (and I mean slowly) seemed to recover. He said it was about a week until the throttle response was normal again.

[Tony]

That is truly a beautiful sound.  I'm surprised it sounds so good running on cold veg to be honest.