LPG burning pistons?

Matt76 · Dec 6, 2009

I was skipping through ebay looking for bargains and there was a D40 engine for sale with 2 burnt pistons due to running on LP Gas, has anyone heard of this before?
D40 turbo diesel engine - eBay Other Engines, Components, Engines, Components, Car Parts, Accessories, Cars, Bikes, Boats. (end time 14-Dec-09 08:08:53 AEDST)

Old.Tony · Dec 6, 2009

LP Gas does increase the combustion temperature and pressure - the extra "go" has to come from somewhere!

The piston crowns are cooled by oil being squirted on their undersides. Under normal conditions that should be sufficient. With LPG injected at normal rates it should just be sufficient.

However - and trucks have faced this problem in the past - inject too much and the engine cooks. Or, flog the guts out of it and the same thing happens.

KraftyPg · Dec 6, 2009

Strangely enough I got an email from a mate on the same topic early in the week. It had a link to a 4wd overlander article but really hadn't made up my mind if this was one of those internet articles to believe or if it was just another story telling us what we should and should run in diesel engines.

The article had the following quote which does lean towards the story the ebay seller is suggesting.

It also became not uncommon to witness broken piston ring lands and holed, seized, or melted pistons through the less than judicious and virtually uncontrolled application of the LPG.

True or not I don't know I haven't made my mind up but heres the web addies to make up your own mind

LPG For Diesels - Equipment Tests - Overlander 4WD Magazine - Australia's leading four wheel drive magazine

Krankin · Dec 6, 2009

Could also be a secondary ignition source in the combustion chamber igniting the lpg at a differing moment to the diesel/air mix creating 2 flame fronts hence pre-ignitition/detonation occuring and hammering holes in the piston :suicide:

And then again could have been a vacuum leak creating very lean fuel mix,

but also could have been...............and so on and so on.

:idea:

maybe he wasnt using 2stroke :big_smile:

KraftyPg · Dec 6, 2009

Krankin said:
maybe he wasnt using 2stroke

Either that or it was synthetic, or maybe it wasn't synthetic

Dion · Dec 6, 2009

Krankin said:
maybe he wasnt using 2stroke

Megalolz

Dave · Dec 7, 2009

Dont think Id run LPG through mine.

Plenty of people haven't had problem's but Id rather not take the risk.

Dave.

maddogrc · Dec 7, 2009

just like performance chips, the engines werent designed in mind to run with another fuel type or designed to run at settings not set originally.

i dont trust them

tweak'e · Dec 7, 2009

thats sounds about right. put to much gas in its going to blow pistons. its not uncommon.
thats a problem with some of the cheap setups as the lpg is poorly metered and can end up with way to much going in.

no different from chipping it and winding the diesel up to much.

rambada · Dec 7, 2009

I've had my Hilux on LPG for ages and no problems at all. However, like anything added on - people can tinker with them and the short term gain of power can wreck the motor. I have mine dyno tuned by the original installer which also measures EGT. Definately not something I play with. The amount of LPG introduced on mine is absolutely minimal - I go though at least 6 x 55L tanks of diesel to 1 40L LPG (I think thats right) and even then, probably use more tanks of diesel than that.

Would I put it on my Navara - no way. Why? Dont need it. Its got more than enough power for my usage. I was considering chipping in the future but not seriously and now that others are indicating that it may be inappropriate, thats easily pushed me towards shelving the idea.

SOLID D22 · Dec 7, 2009

Mines been on gas for ages now and no probs at all, touch wood, but an old man told me his ol friend used to work on diesel engines and diesel was intentially designed to run with lpg.
This has been told to me by an old man that i dont know so dont hold anything against me, but your right too much gas can burn holes in pistons and your right again about the power chips doing the exact same thing and burning holes in pistons, so realistically your damned if you do and your damned if you dont.
We all have to consider we dont know how each person drives, regular services etc etc, i personally think this all helps with longetivity, not one of my cars as long as i have been driving has ever failed on me. Touch wood again!

Martin'sD40 · Dec 10, 2009

My D40 2.5L is on Gas , and has been for 50k no problems what so ever , Most of the damage is done when when you increase the jet size to much ,
a diesel will still ping if you like , when to much gas is added much the same when aerostart is used when glow plugs dont work anymore on older diesels , you get a super fast rattle from the engine

The ratio I use is 2:1 diesel/gas and it works well, the chips I have used in the past never even came close to the power or extra economy the gas gives you. When the system is set up correctly it works well, meaning you cant just bolt it on and expect the full benefits you should also do the exhaust to get rid of the heat faster , When I had my 3" mandrel system fitted I asked for a high flow Cat to be fitted for warranty purposes , my D40 is an 06 plate even though it came std with a Cat Australian ADR rules say I didnt have to have it, now that I'm out of warranty the Cat is gone and the flow is far better now than before

Cheers Marty

Leprechaun · Dec 10, 2009

Martin'sD40 said:
My D40 2.5L is on Gas , and has been for 50k no problems what so ever , Most of the damage is done when when you increase the jet size to much ,
a diesel will still ping if you like , when to much gas is added much the same when aerostart is used when glow plugs dont work anymore on older diesels , you get a super fast rattle from the engine

The ratio I use is 2:1 diesel/gas and it works well, the chips I have used in the past never even came close to the power or extra economy the gas gives you. When the system is set up correctly it works well, meaning you cant just bolt it on and expect the full benefits you should also do the exhaust to get rid of the heat faster , When I had my 3" mandrel system fitted I asked for a high flow Cat to be fitted for warranty purposes , my D40 is an 06 plate even though it came std with a Cat Australian ADR rules say I didnt have to have it, now that I'm out of warranty the Cat is gone and the flow is far better now than before

Cheers Marty

I can't see a cat on mine, is it part of the dump pipe or don't I have one?

Jason · Dec 10, 2009

The Cat on my stock system bolted directly onto the bottom of the dump pipe, its a D22 but a 2.5.

Martin'sD40 · Dec 10, 2009

On the stock system (/05/06/07) the Cat is right at the flange and its all part of the factory dump pipe , unless you remove it you cant see it. another clever way to hide something most of us didnt know we had

I dont know if the o8 is any different but I would say it'll be the same

Cheers Marty

big orse · Dec 10, 2009

Martin'sD40 said:
My D40 2.5L is on Gas , and has been for 50k no problems what so ever , Most of the damage is done when when you increase the jet size to much ,
a diesel will still ping if you like , when to much gas is added much the same when aerostart is used when glow plugs dont work anymore on older diesels , you get a super fast rattle from the engine

The ratio I use is 2:1 diesel/gas and it works well, the chips I have used in the past never even came close to the power or extra economy the gas gives you. When the system is set up correctly it works well, meaning you cant just bolt it on and expect the full benefits you should also do the exhaust to get rid of the heat faster , When I had my 3" mandrel system fitted I asked for a high flow Cat to be fitted for warranty purposes , my D40 is an 06 plate even though it came std with a Cat Australian ADR rules say I didnt have to have it, now that I'm out of warranty the Cat is gone and the flow is far better now than before

Cheers Marty

By your 2:1 ratio do you mean 2l of diesel and 1l of gas? If that is the case you are running at a really high level (33% gas). From everything I have read, anything over 30% can be lethal to your motor.

I definitely agree that the gas gives far better performance over chips.

Martin'sD40 · Dec 11, 2009

I'm well aware that 30% is right at the cut off point, 2:1 was just a quick stab at it , its more 130L diesel 50L gas.

Leprechaun · Dec 11, 2009

How much does a quality gas system cost? do you still get the government rebate or has that finished?

Martin'sD40 · Dec 11, 2009

I dont know if its still on or not , but if your a business you don't get the rebate its for private use only. Whats a system worth it all depends on what your looking for there are systems now that allow you to re-map via a laptop and everything is electrically measured and controlled bla bla bla or plain simple kits where you only change jet sizes, fitted would be around the 4k mark with a 2k rebate or 3k in WA

I bought it trade, fitted my own system and got my local bloke to hook up the pressure side of it , ever installer has a different charge just like every kit is different

Cheers Marty

SOLID D22 · Dec 11, 2009

My gas system cost 4g and got 2g from gov rebate. Its a 30l tank and it uses 25l of gas with every 75l of diesel. The rebate is still around but it is dwindling down slowly.

LPG burning pistons?

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