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Hi All

I am planning on running a bit of SVO in my 200tdi.

To help things along I am going to install a Fuel Filter Heat Exchanger:

http://cgi.ebay.co.uk/Fuel-Heat-Exchanger-suitable-for-Bio-Diesel_W0QQitemZ320514710260QQcategoryZ36631QQcmdZViewItemQQ_trksidZp3286.m7QQ_trkparmsZalgo%3DLVI%26itu%3DUCI%26otn%3D3%26po%3DLVI%26ps%3D63%26clkid%3D8377037812927113447

This should thin the SVO and take the pressure off the pump.

My questions is what will this do when I am running on normal diesel? (Will probably run 100% diesel during cold months)

Will warm diesel make the engine run better or worse?

I know that some cars have fuel pre heaters as standard but am not clear why.

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A chap on another forum had a series with a 200Tdi in it all set up with twin tanks and fuel heating system to run SVO with preheating on pump diesel, he had a carboning up problem to the point that the valve heads were hitting the pistons after about 100miles IIRC, so he went back to straight pump fuel after a decoke, he had a few problems with IIRC power loss as the diesel was hot so the fuel heater had the water pipes disconnected and the problems went away.

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now thats very interesting, I have just bought a 300tdi that the previous owner has fitted just prior to selling & I'm having power loss problems so will be removing over the weekend & changing filter etc.

Hmmm... Sounds like warm diesel is not such a good thing. I might have to rethink my setup!

John - make sure you have the correct fuel filter on for a 300tdi. When I bough my 200tdi 110 it had TD5 fuel filter on it which was restricting the fuel flow. The change in performance with the correct fuel filter was very noticeable.

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why not just blend the deisel/veg at about 70/30 or up to 50/50.

Take the head off your engine and drop the pistons out and take a look at them for why.

I don't think heating diesel is a good thing. I set my 109 up to run on SVO and the 12J engine was fine with it, both using heated SVO and heated diesel. The Tdi doesn't like SVO, though, even when pre-heated, and cokes up rapidly. The Tdi's injection pump also made a regular metallic ringing noise when running on pre-heated diesel which I took as a warning sign that the viscosity was too thin. I have subsequently stripped the system out. SVO works well in indirect injection engines (as long as the pump is strong enough or protected by pre-heating), but is bad in direct injection engines.

To the advocates of running a Tdi on vegoil, I suggest you speak to Turner Engineering to ask them their professional and seasoned experience of the effects of this. For some people, it may work out economically viable - you may save enough money using second hand (free) cleaned vegoil to offset the cost of the number of rebuilds you'll end up doing, but Turner and several other engine remanufacturers all held the same view when I asked them about alternative fuels (including running a petrol engine on LPG) - their view was simply "don't do it".

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When I first converted mine, I was told that putting SVO in the diesel tank has the tendency to release a lot of the carp/crud (technical term) into the SVO and the filters will need changing after a day and week and then probably be OK for the usual period.

I went to a two tank system and 100% SVO, I suspect if the mix was less, it may take longer for the crud to appear

Cheers

Peter

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Snagger-are you talking about mixing svo with diesel, 100% systems that preheat, or both? I only ask because I was planning on running a twin tank system with preheated svo and starting and purging on diesel and I haven't heard many negative comments on this but yours has got me worried! I was also going to make sure the injectors were serviced since I believe poor atomisation can cause problems on svo?

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Take the head off your engine and drop the pistons out and take a look at them for why.

I don't think heating diesel is a good thing. I set my 109 up to run on SVO and the 12J engine was fine with it, both using heated SVO and heated diesel. The Tdi doesn't like SVO, though, even when pre-heated, and cokes up rapidly. The Tdi's injection pump also made a regular metallic ringing noise when running on pre-heated diesel which I took as a warning sign that the viscosity was too thin. I have subsequently stripped the system out. SVO works well in indirect injection engines (as long as the pump is strong enough or protected by pre-heating), but is bad in direct injection engines.

To the advocates of running a Tdi on vegoil, I suggest you speak to Turner Engineering to ask them their professional and seasoned experience of the effects of this. For some people, it may work out economically viable - you may save enough money using second hand (free) cleaned vegoil to offset the cost of the number of rebuilds you'll end up doing, but Turner and several other engine remanufacturers all held the same view when I asked them about alternative fuels (including running a petrol engine on LPG) - their view was simply "don't do it".

i have yet to see any evidence about tdi engines dying some horrible vegetable oil fetish related death. I would LOVE to be educated though.

I see horror stories of this sort "my mates engine threw a rod", "bloke down the pubs cylinder head launched through his bonnet" etc etc etc but never any factual evidence.

Yes, you could have problems running svo by having very poor condition injectors. But more than likely, you will also have simillar problems running diesel too. Poor injector spray patterns fitted to a badly coked engine will cause problems no matter what fuel you run.

As for injection pumps etc, the tdi Bosch injection pump is a million times better than the older lucas CAV pump fitted to earlier landrover engines when running on veg oil. Its a stronger pump, better made and much more resilient. But again, if its in poor condition it will leak, but so will a cav pump.

As a tdi owner than has been running veg oil and diesel mixed in a 50/50 ratio for the past 5 years, i can honestly say i have a good grounding to comment. However i only run straight diesel in the colder months. When the weather is warm, i notice virtually no difference in how the engine behaves on the mix. The only thing i notice is when the outside temperature is marginal (<10C) and when i first drive the truck and the engine is cold, at very light throttle loads at low revs (eg 30mph in 4th on a level road) the engine feels like its hunting between on power and off power and the throttle is a bit harder to feather. This lasts less than 1 mile and once a small amount of heat is in the engine and injectors, it goes away completely. In the middle of summer when its very warm, my ratio can rise to 25 / 75 and i notice no difference at all............

My engine has done 50K miles like this and is currently on 170k miles. No smoke, no oil consumption, consistant fuel consumption (27mpg) and pulls well throughout the rev range. Only thing i do is to service it every 3k miles and run an injector cleaner (10k boost) through it every second service (which i did before switching to veg/diesel mix, so no change to my habits).

Nick

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Hi All

I am planning on running a bit of SVO in my 200tdi.

To help things along I am going to install a Fuel Filter Heat Exchanger:

http://cgi.ebay.co.uk/Fuel-Heat-Exchanger-suitable-for-Bio-Diesel_W0QQitemZ320514710260QQcategoryZ36631QQcmdZViewItemQQ_trksidZp3286.m7QQ_trkparmsZalgo%3DLVI%26itu%3DUCI%26otn%3D3%26po%3DLVI%26ps%3D63%26clkid%3D8377037812927113447

This should thin the SVO and take the pressure off the pump.

My questions is what will this do when I am running on normal diesel? (Will probably run 100% diesel during cold months)

Will warm diesel make the engine run better or worse?

I know that some cars have fuel pre heaters as standard but am not clear why.

Somewhere I read that 33ºC is the optimal temp for diesel before injection.

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I run diesel start/stop and veggie in-between and have run that system for three years and used it with 100& SVO all the way through our last through winters! I support the comments about Bosch pumps, don't even consider doing it, preheated, mixed or otherwise with a Lucas pump -they have a terrible reputation.

Cheers

Peter

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Snagger-are you talking about mixing svo with diesel, 100% systems that preheat, or both? I only ask because I was planning on running a twin tank system with preheated svo and starting and purging on diesel and I haven't heard many negative comments on this but yours has got me worried! I was also going to make sure the injectors were serviced since I believe poor atomisation can cause problems on svo?

Both.

I tried my 300Tdi RRC on 75% diesel 25% new rapeseed oil (rapeseed and sunflower are the good oils to use, palm and soya are full of fats and also have higher viscosity). It was immediately down on power and had surging problems at 1500-1800rpm, only fixed when I eventually replaced the pump. The system had been cleaned with several doses of the premium brand treatments and had new filters and injectors, but that made no difference - the mild SVO cold mix damaged the injection pump (which had done about 130,000 miles, so was admittedly a little tired already).

My 109 ran beautifully on heated rapeseed and sunflower oil with a multi-tank system with no apparent problems with the 12J engine. In fact, it was noticeably smoother and quieter with no smoke or performance loss. However, I replaced that engine with a 200Tdi I built up from scratch, complete with re-bore, new pistons and all new injection system. The engine was run for the first 500 miles on diesel only, then the next 500 with SVO once warmed up, purged at the end of each run. Excessive breathing and oil consumption led to removal of the head, which showed heavy coking of the piston crowns and vertical marking (hard polishing rather than scoring) of the bores by carbon deposits on the sides of the crown that would soon have led to scoring. The rings are all contaminated and choked.

Indirect injection engines react well to SVO because the spray doesn't condense on the piston or bores, but the same can't be said for direct injection engines like the Tdi. Like I said, the engine remanufacturers, especially Turner, find a lot of problems with engines run on vegoil, regardless of whether they have multi-tank systems with pre-heaters or not. If you have a source of cheap or free used oil and can filter the crud and water out, then it's cost effective to use it, especially with current fuel prices, but it's not worth it if you're buying vegoil.

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