V8 LPG install

[Jon Wildsmith]

The 2 or 3 places I've checked with all said Flashlube or equivalent is needed for these engines so for the little bit of extra running cost I'll go along with them but if where you have yours fitted says different let us know Mine was inspected and certified by a local installer

I run on petrol quite a lot but I don't see how that's going to stop valve reccession occuring when I'm running on LPG, other than it meaning I do less miles on LPG.

 

[Dark Dude]

Jon

I can only go by my experience.......

I'm going to have a word with my "expert" to see what he says, as well as the boys down at Hilton LPG (Wolverhampton). But for the initial cost, I kind of agree with you. Always err on the side of caution. Better safe than sorry.

John

The Dark Dude

 

[Dark Dude]

BTW: Jon

After a year of happy motoring, what kind of MPG figures are you currently getting out of your LPG install?

John

The Dark Dude

 

[Jon Wildsmith]

It's hard to know the consumption figures, I don't keep track of how many miles on the trip meter were LPG and how many petrol so a rough guess is about 12 round town and 14 on a run. I'd guess petrol is now only about 1mpg better for both. Factor in that mine is modified and I'm not noted for economic driving and you should get a couple more mpg.

 

[Dark Dude]

Jon

You're a better man than me, having a lead foot with a throttle attached to a 4.7 V8.



John

The Dark Dude

 

[Gav Peter]

He only does four miles a month though

 

[karl webster]

Giving someone else a hard time for a change gav

Like it when it's not me

 

[Jon Wildsmith]

Cheek, it's at least 6

 

[karl webster]

 

[Gary Stockton]

Saving up for Spain no doubt ...

 

[Jon Wildsmith]

last month we visited my parents, that's 120 miles I'm not sure that many miles are good for it, I'd better give it a rest this month

 

[Dark Dude]

Jon

It's my understanding that FlashLube and Valvecare (Prins) is essentially an additive which replaces those lost to the engine with the reduced use of petrol.

Is this understanding right or wrong?

John

The Dark Dude.

 

[Jon Wildsmith]

My limited understand is that LPG burns hotter and slower than petrol and this means the valve seats get much hotter and recession is more likely to occur than when running on petrol. Somehow the additive is supposed to reduce the rate of valve seat recession, could be snake oil for all I know but I'll give it the benefit of the doubt for the little extra it costs once set up.

 

[Dark Dude]

This is what the good people at PRINS have to say about the matter:

"ValveCare

Developed to provide solution for increasing numbers of engines which are affected by valves and valves seats when using LPG.

Petrol, as a fuel, includes additives which protect & coat valves and valve seats however this addititive is not found in LPG fuel. Therefore some engines are not suitable for LPG conversion unless a solution is available, for this Prins have the Valvecare system and the benefits include:

* Applicable on all engines equipped with a Prins system
* Always the correct dosage of ValveCare additive based on the actual LPG/CNG consumption
* Economical consumption of additive due to its correct dosage
* Decreases valves and valve seats’ wear
* Fully automatic operation
* Also applicable for turbocharged engines
* Optimal performance, even on heavy loads
* Equal dosage of ValveCare additive over all cylinders through the unique dosing unit
* Buzzer of Prins system will sound when running out of ValveCare additive"

Maybe I'm wrong but this sounds a awful lot like running on petrol at little more will do EXACTLY the same thing as running on Flashlube full time.

John

 

[Jon Wildsmith]

Maybe I'm wrong but this sounds a awful lot like running on petrol at little more will do EXACTLY the same thing as running on Flashlube full time.

I don't think the additive in petrol creates a residual protection that would carry over into running on LPG, more an instantaneous effect each combustion cycle, but I could be wrong.

 

[Rob]

But wont it be cheaper to run flashlube than to run a tank of petrol every now and then? Surely its cheaper in the long term.

 

[Dark Dude]

This is how I see it. As long as FlashLube (and other similar products) doesn't do any harm, better safe than sorry. In the grand scheme of things £150 isn't a big deal. I'm going to have one installed in the near future, when I've got a few pennies saved away from the wife.

John

 

[Singhabeer]

I bought a v8 about 18 months ago and i noticed it started running poorly not long after. A compresseion test revealed low compression on 5 cylinders. Heads off and some of the exhaust valves had large splits in them but about 12 of the 16 exhaust valves had valve recession. The seats were not to bad with i would say minimal damage caused by the knackered valves. I had 16 new valves ordered from Toyota and had them reseated and it now runs like clockwork. I had a flashlube system fitted straight after but i dont know which make/model it was. The lube costs about £15 a litre and last ages as long as its calibrated correctly .
I would not use LPG on this engine without some sort of lube system . It cost me nearly 2k to sort the damage out and that was me doing it myself . But now its lovely and smooth and i would guess it does about 15 to the gallon on lpg(75p) compared to 18(145p) on petrol.
I am now very happy with it and have done about 8000 miles without any issues at all, but please learn from my mistake .

 

[alokin]

i would explaing valve seat recession trough two factors:
a) lpg burns hotter than petrol AND is injected in form of gas thus does not have effect of "cooling" as petrol does (which is in liquid form)
b) lpg burns cleaner. good for enviroment but bad for your engine which was engineered for petrol. petrol leaves a bit of residues when it burns so valves and their seats were designed to solve that. how? simply trough the proces that they are designed not to have super smooth surface and the valve rotates a litle bit with each opening/closure. when there are no residues from petrol, this effect of "sanding paper" manifests in valve "eating trough" its valve seat. this is where flash lube comes in place- it recreates impurities of petrol, it is additive only for that.

 

[Dark Dude]

Right now I'm NOT a happy man as regards this whole issue of valve recession. Prinns recommend their own system called Valvecare which according to both Neil at Medway Dual Fuel and Billy at Hilton LPG is a piece of crap. I'm going to give the guys at Tineytech a call to see what they can do for me but I want this sorted and sorted NOW! I haven't got 2K burning a hole in my pocket......

John