Lpg - A Cautionary Warning

[intumult]

Talking the other day to the guys who run the mini-buses and have heard that 4 / 10 conversions they have had done have had problems needing expensive engine repairs and naturally, time off the road.

Now, I do not know if the fact they are mini-buses and doing high mileage has anything to do with it but most problems are occuring within 3 months or so.

All these conversions were done in Rangsit.

Personally, I have had - as said in previous posts - a few teething problems but nothing serious.

On the other hand, if this info helps or stops one person having expensive problems then the minor effort of posting will be worth it.

[BigSnake]

Hmmmmmm!! Thanks for the headsup, need to rethink my plans to convert.

[Thaiboxer]

If done properly, LPG should be safe and effective. I've never heard of any confirmed cases of engine problems related to LPG. The main thing to worry about is how well they do the connections; you need to make sure there are NO leaks!

[Crossy]

Are these vehicles LPG conversions of gasoline (which as thaiboxer noted should be safe) or NGV / Diesel dual-fuel conversions?

NGV / diesel can have serious issues if the gas mix is not carefully controlled, also it needs adjusting because of the variable calorific value of NGV. BMTC and SRT had some problems a couple of years back with dual-fuel conversions frying the engines

[intumult]

Well, with only a 1 month guarantee for a job that cost me 38k (after selling the diesel engine) seems to me that 4/10 is far too high a ratio of breakdowns.

I know, now, there are a few small places that do conversions and seem to be clued up and we are getting a new LPG/NGV conversion station here soon.

I am not trying to imply that other places do a bad job of work but I would seriously look at past work if I could, or get an extended guarantee if possible.

Maybe a trip to the local LPG garage and asking there or people who gas-up there for places that do reliable conversions would be a good idea??

BigSnake ... no probs. Like I say, if it helps 1 person

[intumult]

Are these vehicles LPG conversions of gasoline (which as thaiboxer noted should be safe) or NGV / Diesel dual-fuel conversions?

NGV / diesel can have serious issues if the gas mix is not carefully controlled, also it needs adjusting because of the variable calorific value of NGV. BMTC and SRT had some problems a couple of years back with dual-fuel conversions frying the engines

All the problems are with Toyota mini-buses converted from diesel to 91/LPG with replacement engines.

One who has NGV has had no problems.

[Crossy]

Are these vehicles LPG conversions of gasoline (which as thaiboxer noted should be safe) or NGV / Diesel dual-fuel conversions?

NGV / diesel can have serious issues if the gas mix is not carefully controlled, also it needs adjusting because of the variable calorific value of NGV. BMTC and SRT had some problems a couple of years back with dual-fuel conversions frying the engines

All the problems are with Toyota mini-buses converted from diesel to 91/LPG with replacement engines.

One who has NGV has had no problems.

I'd be concerned about the quality of the replacement engines or were they new, in which case it would have been smarter to buy the vehicles with gasoline engines in the first place.

[intumult]

Ah, now, I do not know if they were replacement engines.

[lingnoi34]

You must consider when converting to LPG that:

lpg burns hotter than gasoline and your engine must have "hard" valves or else they will be burned. many jap cars have soft valves (Honda, Toyota, Mazda)

the shop doing the conversion must have sufficient experience with your model car in order to do correct job and adjustments

LN

[basjke]

Are these vehicles LPG conversions of gasoline (which as thaiboxer noted should be safe) or NGV / Diesel dual-fuel conversions?

NGV / diesel can have serious issues if the gas mix is not carefully controlled, also it needs adjusting because of the variable calorific value of NGV. BMTC and SRT had some problems a couple of years back with dual-fuel conversions frying the engines

All the problems are with Toyota mini-buses converted from diesel to 91/LPG with replacement engines.

One who has NGV has had no problems.

I tought NGV and LPG are the same thing just another name.Anyone can explain the difference please.

[Plus]

If they needed engine repairs we need to know what engines they were.

From the price quoted it appears they installed the older, non-injection systems that are not suitable for variable valve engines and can lead to engine knocking with serious consequences.

Injection type system alone cost 35k.

I suspect guys went to 1JZ vvti but more details from OP would be appreciated.

[intumult]

If they needed engine repairs we need to know what engines they were.

From the price quoted it appears they installed the older, non-injection systems that are not suitable for variable valve engines and can lead to engine knocking with serious consequences.

Injection type system alone cost 35k.

I suspect guys went to 1JZ vvti but more details from OP would be appreciated.

In what respect - me being a bit numb (dumb) today would you like details of the engines?

1JZ vvti ?? same as above, dumb today

Then I can ask

[Crossy]

I tought NGV and LPG are the same thing just another name.Anyone can explain the difference please.

They are very different, look here for enlightenment http://www.thaivisa.com/forum/index.php?s=...st&p=799996

[Plus]

If they needed engine repairs we need to know what engines they were.

From the price quoted it appears they installed the older, non-injection systems that are not suitable for variable valve engines and can lead to engine knocking with serious consequences.

Injection type system alone cost 35k.

I suspect guys went to 1JZ vvti but more details from OP would be appreciated.

In what respect - me being a bit numb (dumb) today would you like details of the engines?

1JZ vvti ?? same as above, dumb today

Then I can ask

1JZ seems to be the most popular engine for swaps like that. It has been in production for over fifteen years and it has gone through several modifications - single turbos, twin turbos, vvti, vvti+turbo. You yourself have a 1JZ in your Mitsubishi. Is it VVTi? Judging by the price, it isn't. Older model, but more reliable when coupled with vaccum mixer LPG.

I am simply exploring the possibility that engine problems in those vans come from installing crude LPG system on sophisticated engines. It's not recommended by Toyota and they void the warranty in these cases (in Europe).

I'm in the process of doing a similar swap myself and I insisted on installing injection LPG. Initially they only warned me about possibility of engine misfire with cheaper LPG but said it's not likely to cause any damage. I decided it's better be safe than sorry. Maybe my fears are misplaced, I only researched this stuff on the internet, I don't know the exact proportion of cheap installs going wrong. Some said it was three out of three, on Lexus. That sucks.

Our insurance guy converted his petrol Vigo, 2.7l VVTi, to LPG injection about a year ago and his engine never had a single case of knocking.

As for the question - you said they had engine problems. Naturally it's important to know what kind of engines and what kind of problems. By now they have probably figured out themselves what went wrong.