Myths and fairy tails about the VM TD

[Deezelweazel]

Did you install a lift pump(Hardy) to support the IP?
Did you increase the diameter of the fuel hoses?
... just being a bit nosy...

[The Smiths]

Originally Posted by Deezelweazel

Did you install a lift pump(Hardy) to support the IP?
Did you increase the diameter of the fuel hoses?
... just being a bit nosy...

No modifications - pour and go.

Though acetone does help with the spray pattern at injectors - by reducing the surface tension of the oil (used at 0.1/0.15%)

And petrol at 5% in winter thins the oil to similar to diesel, though it is then best to use cetane improvers.

This forum is very good (this links is also to a discussion on water injection)

http://www.vegetableoildiesel.co.uk/....php?tid=17984

[The Smiths]

There are also people running diesels on hydraulic fluid, old engine oil etc

I won't even mess with used veg oil

[Deezelweazel]

Yup, heard about that used motor oil thing- stupid, because main filters go down to 20micron. fuel filters go to 3micron. Ask every engine builder and they will tell you that particles less 3micron do a lot damage to bearings,(charger, IP) piston ring gaps.
Avalanche effect for those who want to learn more about it.
Wear does not appear suddenly it's a sneaking process.
Saving is on thing -but if you have to spend more in the end it is debateable.


Acetone is one of the strongest cleaners (!)we know. It is very agressive to pump and rubbers seals. They get brittle and crack.
Not a good idea at all.
Where do you get that with the surface tension? Do you know what Diesel is?
Spray pattern is not surface tension based. It's viscosity based. Winter Diesel or Diesel No1 has a higher viscosity- but runs like crap.
Adding gas was allowed with old injection system- you can't do that without causing extreme wear.
Of course you can do that, if you don't care...
Those running hydraulic fluids have never seen swollen hoses and damage hydraulic fluid causes.
Sometimes it is not try and error -sometimes chemical laws do work and prohibit use of those fluids.

cetane improvers do only advance ignition in electronic controlled engines like ours. so engines will run hotter.the "effect" is not a gift for our engines.

The use of fuels other than Diesel does not improve reliability and durability- so they will not be mentioned here again.

[Antiferret]

Originally Posted by The Smiths

What are your thoughts on water injection?

Where it is introduced as a mist into the air intake. Some claim an increase in economy and performance - plus cleaning effects (used quite extensively with vegetable oil on other engines - normaly direct injection where they can suffer from ring gumming with veg oi, but the water clears it)

With the soot/oil build up it is shocking how quick it builds up. I changed some exhaust gaskets and cleaned the intake, 2 weeks later (when head gasket was being changed as that had gone - as well as exhaust manifold gaskets) - it needed cleaning out again

and I would recommend cleaning the intercooler out - shocking what a difference it makes

you could try steam injection. (utilising waste heat from exhaust)

guranteed small droplets. no special pump. probably wont increase peak power but will increase the thermal efficiency of the overall engine and de coke it to boot!. have it switch off until engine comes to temp and turn off completely at idle. you want to minimise condensation on short trips and if left overnight.

[The Smiths]

one of the things of water injection is that you are introducing a liquid into the cylinder (in a controlled manner), which expands and adds more bang for your buck - also it is endothermic and removes heat, rather than add heat and overcook the heads - which is why fitting LPG to a VM engine is a big no-no

But as said none of these are in Weazels area of improving reliabilty on a normal VM engine - they are more in alternative fuels - which others have done extensive research and testing on

[Deezelweazel]

These methods are all temporary limited.

Steam is already temperature saturated- you won't get a remarkable cooling gain.
Adding power to this engine demands the use of head studs instead of bolts.
($$$!)
If you have a closer look at this engine you will recognize that it's exhaust lines are located below the water bridge.
The exhaust heat is directly transfered into the coolant system. Which is good and logical.
The intake is located towards the engine front. Nothing can be done to prevent heat to dissipate in that direction. Coolant flow is also limited here.
The front engine block coolant lines are relatively constantly flushed with coolant. The rear ones are neglected- one reason for the more often rear head failure.

So, what can be done here.
-lowering the general coolant engine intake temperature.
does does do belong to the coolant system too- of course in a smaller
percentage, but you have top grab every cooling advantage you can get.

- Again, if the coolant circuit isn't in top shape- you will have to deal with heat problems.( this rule is applicable for the gassers, too)
To check this you can measure your coolant exit temperatures and the coolant intake temperatures. A temp drop of 12°C is very good, anything less than 8°C is critical.
So if you don't stay within these limits you ask for trouble.

The VM engine has a small radiator volume compared with other 2.5l engines.
A small volume directly transfers into less heat transfer.

I neglected under hood temperatures in the past, the drop of 5°C is not worth to mention it. Heat is stored in the block and in the coolant, not in the air under the hood. Air acts as an insulator. Maybe I get rid of 5° underhood temperature- but I do influence the radiator fan and heat dissipation.

Again, the main target is the radiator and the heat exchange- all other aspects than heat exchange is playing around.



LPG in a Diesel?

Combine propane and its 110-octane rating with diesel's 15 to 2S-octane rating, you're set up for a bad case of detonation if conditions in the combustion chamber are right (or wrong).

What happens is the propane, because it's in vapor form already, is dispersed throughout the combustion chamber and reacts more quickly with the available oxygen molecules once combustion begins.

The first part of the diesel cycle goes okay; the diesel fuel is injected and starts to react at the lower temperature. But as soon as the temp is high enough the propane starts grabbing the oxygen generating a lot of heat and pressure quickly.
This happens so quickly in fact that the diesel being injected doesn't have a chance to burn correctly, it just collects in the combustion chamber. The fast burn of the propane raises the pressure high enough to surpass the detonation limit of the unburned diesel fuel, causing it to ignite in pockets within the combustion chamber(valve pockets in the piston head).
The flame fronts collide at inopportune times (detonation).

This is not a controlled compression ignition and will hurt your engine.
Be careful with experiments.