1FZFE - LPG install

[Beast of Berlin]

Hi everyone,

I am facing the decision of an LPG install for my 1FZFE (rising fuel prices - currently 1,94€/ltr).

Are there major concerns to ruin the engine in the long run? Anyone who has good/bad experience?

By the way, last summer the head gasket got blown after 304000mls. Combustion would be even hotter running LPG contributing corresponding effects.

 

[mudgudgeon]

Yes, combustion gas is hotter with LPG

LPG produces less power (unless injected as a liquid), and uses more litres per 100kmthan gasoline/petrol, so you lose overall range between refueling.

You also lose cargo space of you put a tank inside, of lose ground clearance of you put tanks underneath.

Many Australian vehicles are/where converted to run on LPG because LPG was heavily subsidised by the Federal government making it very cheap.

Lots of vehicles burn exhaust valves, and wear valve stems and seals faster because seals are no longer lubricated with liquid petroleum from the air/fuel mix.
Many vehicles get fitted with a drip feed lubrication system to lubricate valve stems.

I've weighed the cost of installation, certification etc of LPG in the past, and with subsidies on fuel costs, it was still a 7-10 year payoff based on fuel savings on moderate mileage (15-20k/km per year).
In Australia, LPG tanks need to be pressure tested and re-certified every 10 years. This along with maintenance of the system generally means that your 10 year pay back just evaporated.

Evaporator systems don't like cold weather. Many vehicles need to be started running on petrol, them switched to LPG.

In Australia, LPG can be hard to find in smaller towns. In cities, you'll find your regular refilll spots.

Personally, anytime I'm looking for another vehicle, a vehicle that has an LPG system is given a hard pass. Even if everything else was perfect, I'm scratching that vehicle off the list.

 

[thelal]

I've an Italian BRC 5th gen injection system on my 97 petrol. Runs fine but I don't do a lot of mileage on it. I know my oil is very clean on replacement when I've been running more on LPG. Will likely add a drip feed system to mine but planning on checking valves at some stage to gauge 'light' usage. I rarely go above 2500 RPMs on mine ; slow n easy. Based in Ireland and very little LPG filling stations around. UK better and most of Europe plenty of supply.
You need to weigh up cost (installation, running) vs savings vs wear-n-tear (perceived or otherwise). Certainly learnings from Aussie friends as they've been running LPG on their 80s for a lot longer than most other countries. There is a TLC UK group as well (FB & web) that has some other users for 80 usage.

 

[robnicko]

My experience..

I bought my 95GXL new in 1995 and converted to LPG in 1999 (approx 68k on the clock at time of conversion). Nothing to do with the Govt schemes or anything
HG went at 480k (between cyl 5&6) which I fixed at home and now sitting at 530k
It runs the Impco mixer (vapour) / B2 converter and 120L tank
The converters can fail internally with seals etc however are around $350 to replace with a new one here in Aus or can be rebuilt if only a seal issue.
Combustion temps are hotter due to LPG being a dry fuel and its burning characteristics so I run the Flashlube drip feeder into the intake, 1 drop every4-5 seconds to lubricate the valves / guides - this runs regardless of LPG or Petrol. Valves need to be checked for adjustment every 40k when running on LPG
I also run spark plugs 1 class colder - NGK-BKR6EYA and std GAP along with timing at 3DegBTDC. Spark plugs I change every 30000kms

I recall at the time of converting a friend who's a qualified mechanic said to me 'always start on Petrol and run for at least 10 min before switching to LPG and always turn off vehicle overnight on Petrol'. I have religiously done this and to be honest only use LPG if I know it will be for a good run and contribute this to the longevity before the HG went which at 480k for a dual fuel 1FZFE is damn good.

Performance wise I find low down torque better on LPG however in the mid to upper rev range Petrol is king. Normal day to day driving to be honest there is hardly any difference.
Economy wise - around town I find LPG to get around 5.5km/L and 6-7km/L highway driving @100km/h & Tyres at 40psi

At the time of the HG going there was some valve seat recession evident on the exhaust valves but not as much as would have should the Flashlube not been used. Regardless all valve seats were changed to hardened stainless / LPG compatible ones. Valves were cleaned up & reused as they were still in spec.

I imagine if you were to convert in 2022 it would be an injected LPG system and when tuned correctly these systems can make really good power and the difference between petrol / LPG would not even be noticed. My parents used to have a 93 400SEL V8 with injected LPG and it drove much better on LPG than petrol

At the end of the day LPG is a cleaner fuel however most of the issues people have had in regards to performance and engine issues relate to the quality of the installer and their workmanship. As the previous poster said, availability can be an issue in some places but most have it. Unfortunately it too has risen in price as a crazy level compared to Petrol which is purely gouging - it was 9.5cpl when I first installed LPG and now 91cpl

Maybe Ive been lucky with mine but I think it a good alternative if done right but believe the fact I run on Petrol first & last and LPG only in between when at proper operating temp is a contributing factor as well.

Rob

 

[thelal]

...'always start on Petrol and run for at least 10 min before switching to LPG and always turn off vehicle overnight on Petrol'. I have religiously done this and to be honest only use LPG if I know it will be for a good run..

I do the same.
It will be interesting (on my agenda) when I get around to doing a valve adjustment to see what repercussions of running LPG (w/o Flushlube) and before I start a Flashlube install