My veg oil conversion - update

Little update on the water injection project 10,000 miles ish on from completion.
Worked well - ie you would not know it was on or indeed doing anything except using water. Albeit it uses quite a lot and is now set to .8 bar on ie nearly full boost.
It needed a new Suco switch, this time a stainless bodied one and the feed is now off the turbo (dry) rather than the manifold (wet) as it corroded the internals slightly and started playing up. Hopefully all is now well as the switch was over £100. Fitted a bleed valve to the WI as well to allow easy purging when I accidentally run out of water and the system gets air in it.
Few mods to the veg system (see pics) including a further sedimenter for the diesel start system, plus new fuel pump for the Eberspacher now in with other pumps in the locker.
Oh did I mention a brand new injection pump! For a money saving project this is struggling to make sense but as inspiration for anyone putting together the complete package its worth a look.

Looks like a plumbers nightmare!

why are you doing all this? mpg? (the water bit)

Jubilee clip porn.

trax said:

why are you doing all this? mpg? (the water bit)

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Most direct injection engines suffer from ring gumming when run on veg, water injection is known to clean the polymerized veg from around the rings.

That said the 200/300tdi is not generally a problem on veg, plus the polymerization is mainly a cold start problem and as it's been twin tanked I personally can't see why crowman has gone to these lengths.

That looks like a nightmare. I run a standard twin tank system on mine and it work perfectly well, this seem like a lot of effort.

My landy starts on diesel, and once the engine is warm after about 5miles or so I flip it onto veg. Then once I need to stop (for an extended period) I switch it back to diesel for the last 5 miles of my journey to purge the system.
I do a 500mile round trip every weekend on full veg oil and I haven't had any "gumming" of the rings. Im running a standard lift pump, a heater exchange to warm up the veg oil beforehand, a switchover valve and a small inline filter. The system works great.

James_mac said:

That looks like a nightmare. I run a standard twin tank system on mine and it work perfectly well, this seem like a lot of effort.

My landy starts on diesel, and once the engine is warm after about 5miles or so I flip it onto veg. Then once I need to stop (for an extended period) I switch it back to diesel for the last 5 miles of my journey to purge the system.
I do a 500mile round trip every weekend on full veg oil and I haven't had any "gumming" of the rings. Im running a standard lift pump, a heater exchange to warm up the veg oil beforehand, a switchover valve and a small inline filter. The system works great.

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what other tank did you use?

markSX said:

Most direct injection engines suffer from ring gumming when run on veg, water injection is known to clean the polymerized veg from around the rings.

That said the 200/300tdi is not generally a problem on veg, plus the polymerization is mainly a cold start problem and as it's been twin tanked I personally can't see why crowman has gone to these lengths.

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ah cheers.

trax said:

what other tank did you use?

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It's a 25L marine fuel tank. I just sits in the back where one of the rear seats used to be. I'm planning on fitting a td5 rear fuel tank at somepoint tho.

Where does the fuel return go to ? cant understand how twin tanks for different fuels work unless twin return pipes are used

markSX said:

Most direct injection engines suffer from ring gumming when run on veg, water injection is known to clean the polymerized veg from around the rings.

That said the 200/300tdi is not generally a problem on veg, plus the polymerization is mainly a cold start problem and as it's been twin tanked I personally can't see why crowman has gone to these lengths.

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Ring gumming with veg oil is certainly an issue, after some many 10,000's of miles however the OP could have saved himself the hassle and just made proper bio diesel which doesn't cause the issue to the same extent. You can also buy fuel detergent additives which prevent this.

Also, his injection pump will pack in before ring gumming becomes an issue and I am talking about MANY miles later here. The disco will have rusted off the road beforehand.

I think I will just stick to properly made bio fuel and some additives to help in the cold.

discomania said:

Ring gumming with veg oil is certainly an issue, after some many 10,000's of miles however the OP could have saved himself the hassle and just made proper bio diesel which doesn't cause the issue to the same extent. You can also buy fuel detergent additives which prevent this.

Also, his injection pump will pack in before ring gumming becomes an issue and I am talking about MANY miles later here. The disco will have rusted off the road beforehand.

I think I will just stick to properly made bio fuel and some additives to help in the cold.

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i agree iv done 20k miles on either bio or svo different make car with no issues i refurbed the ip but that was done to the low sulphur diesel at the pump when they switched

biketeacherdave said:

i agree iv done 20k miles on either bio or svo different make car with no issues i refurbed the ip but that was done to the low sulphur diesel at the pump when they switched

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That ULSD is a pain in the neck. I chuck a little engine oil to keep the fuel oily to help up the lubricity if I'm running 100% pump fuel - I'd use 2 stoke oil but it tends to be red - next time I see the green 2 stroke I'll buy some of that.

If on bio not a problem really.

You'd have to put a lot of two stroke in to make your diesel even slightly pink - 5% is all you need.

discomania said:

Ring gumming with veg oil is certainly an issue, after some many 10,000's of miles however the OP could have saved himself the hassle and just made proper bio diesel which doesn't cause the issue to the same extent. You can also buy fuel detergent additives which prevent this.

Also, his injection pump will pack in before ring gumming becomes an issue and I am talking about MANY miles later here. The disco will have rusted off the road beforehand.

I think I will just stick to properly made bio fuel and some additives to help in the cold.

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I started running veg but moved over to bio a few months later, been running bio for 5 years now and covered many many miles.

I don't use additives in the winter unless the feedstock is semi solid.

mick the builder said:

Jubilee clip porn.

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Thank you - all stainless and sadly un avoidable!

markSX said:

Most direct injection engines suffer from ring gumming when run on veg, water injection is known to clean the polymerized veg from around the rings.

That said the 200/300tdi is not generally a problem on veg, plus the polymerization is mainly a cold start problem and as it's been twin tanked I personally can't see why crowman has gone to these lengths.

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I guess the principle reason is this car will never be sold, so all efforts are for the long term - God knows the number of hours I have spent (and £££) improving/restoring cars over the years only to flog them a month or so later and watch all my time and effort drive up the road for no real return.

As for the system fitted - simply put it is over engineered using the best components on the market. I can switch both fuels over in less than 20 seconds and divert both fuels to loop or return.

The Eberspacher remotely starts and warms the cabin and the dual heat exchangers so the veg oil can be switched over within a minute of starting or using the engine heat alone within 4 miles - this while the cabin is warming up too, good going for a Fender?

Finally the water injection is there to assist in the cleaning of the engine - its already over cooled with a massive intercooler. But extra cooling at max boost never does any harm?


The water injection pump.... and the split charge system.

discomania said:

Ring gumming with veg oil is certainly an issue, after some many 10,000's of miles however the OP could have saved himself the hassle and just made proper bio diesel which doesn't cause the issue to the same extent. You can also buy fuel detergent additives which prevent this.

Also, his injection pump will pack in before ring gumming becomes an issue and I am talking about MANY miles later here. The disco will have rusted off the road beforehand.

I think I will just stick to properly made bio fuel and some additives to help in the cold.

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Hopefully not - The pump only ever handles warm/hot oil and although it was brand new I had the principle seals changed to Viton before installation. I am expecting it to handle both fuels perfectly well.

The valves fitted are similarly suited to both fuels....

markSX said:

I started running veg but moved over to bio a few months later, been running bio for 5 years now and covered many many miles.

I don't use additives in the winter unless the feedstock is semi solid.

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I just put it in because it gets bloody cold here, and I can get the stuff almost for free.

Saltlick said:

You'd have to put a lot of two stroke in to make your diesel even slightly pink - 5% is all you need.

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Need to point out that this is wrong sorry

5% is a 1:20 mix!!!!

My CR500 runs on 1:45 for gawds sake.


250ml of cheap ash based 2 stroke makes a good difference in a full tank.

filling up 5% at £4 a ltr would be quite an expense (and thats the really cheap 2 stroke oil that I wouldnt put in a petrol engine!)