Engine 850: B5234T/2.3/20v/T5: THE definitive word on LPG for T5's....

[classicswede]

I've never seen any valve seat problems on these engines at all. If you are conserned about this then get flashlube fitted at the time of conversion. If anyone has seen valve problems it will most likely be due to lean running that should not happy with a good system.

[jimathan]

Originally Posted by classicswede

I've never seen any valve seat problems on these engines at all. If you are conserned about this then get flashlube fitted at the time of conversion. If anyone has seen valve problems it will most likely be due to lean running that should not happy with a good system.

I don’t want to be rued, but that should read rich mixture will make it overheat. (When running on Gas) the opposite of petrol.
Jim

[classicswede]

No still the same lean mixture will cause overheating. Rich mix does not cause problems like that.

[jimathan]

This is a direct quote from the registered LPG installer that certified my car after I had converted it. (He is also a professor of science)

“LPG has a lower calorific value than petrol, about 20% lower.
This means it has less “power” than petrol and consequently burns cooler than petrol.
Petrol burns much hotter than LPG. Petrol is a liquid at the point of injection or carburation. As it vaporises it draws heat from the engine, and this has a cooling effect, thus if the mixture is lean less cooling takes place and the engine overheats.
LPG is a gas at the point of injection or carburation and therefore does not draw any heat from the engine. Although it burns cooler, because it doesn’t draw any heat from the engine, overall temperature is slightly higher. The more you put in, the hotter it burns.”

He goes on to say that because carbon deposits are reduced by over 70% when running on LPG, The oil does not become contaminated as quickly, engine wear is greatly reduced, and therefore the time between oil changes can be increased substantially.

[bb54]

hmmmm, any1 with an 850 T5 convert in the East of please pm me for a meet/demo of how your car runs butane.

wayne

[classicswede]

Originally Posted by jimathan

This is a direct quote from the registered LPG installer that certified my car after I had converted it. (He is also a professor of science)

“LPG has a lower calorific value than petrol, about 20% lower.
This means it has less “power” than petrol and consequently burns cooler than petrol.
Petrol burns much hotter than LPG. Petrol is a liquid at the point of injection or carburation. As it vaporises it draws heat from the engine, and this has a cooling effect, thus if the mixture is lean less cooling takes place and the engine overheats.
LPG is a gas at the point of injection or carburation and therefore does not draw any heat from the engine. Although it burns cooler, because it doesn’t draw any heat from the engine, overall temperature is slightly higher. The more you put in, the hotter it burns.”

He goes on to say that because carbon deposits are reduced by over 70% when running on LPG, The oil does not become contaminated as quickly, engine wear is greatly reduced, and therefore the time between oil changes can be increased substantially.

I'll answer this a bit back to front but here goes.

The reduced carbon deposits is part of what keeps the engine clean and gives the engine a longer life but the more important factor is that beacuse LPG is dry it does not dilute the oil. A engine fuel only be LPG will be much cleaner and the oil life extended much further than a BI fuel engine that starts on petrol and therefore has the oil diluted.

Yes LPg does have a lower calorific value than petrol hence the reason for increased fuel consumption (more fuel used per mile). However your freind is wrong about the burn temps or you have missunderstood his explination. EGT's when running on LPG are higher than when on LPG. This is partly due to the fact that LPG has no cooling ability as it is introduced to the engine as a warm vapour. Running LPG over rich does not help with cooling for this reason.

Regardless of which fuel used running the engine overly lean will result in stress to teh valves and a srtong likely hood of a vlve burning out.

[Volgrrr]

I've been thinking about converting my '95 T5 wagon over to LPG for a while now, and therefore I've found this thread to be both very helpful and informative.

I've owned a number of cars that ran on LPG previously which put up very high, basically trouble-free, mileages (the best was a Holden Commodore V8 which put up nearly 1,000,000 kms from the time I bought it new until my son-in-law sold it some 20 years later).

What concerns me about the Volvo is the number of sensors and computers it has. How do these items respond to the LPG conversion, e.g. the engine management control light?

Does the trip computer still function acurately?

I'm interested to know.

[classicswede]

For these you need to use a modern ecu controlled multi point injection gas system. These systems are driven off teh petrol ecu allowing them to intergrate and used correctly perform faultlessly.

[Muscas]

WoW, interesting thread!

I am keen on the idea of doing such a conversion, I recently was involved in a road accitent in my Renault Laguna which got written off, hence I have decided to use the Volvo as the daily drive irrespective of petrol costs.
BUT!! As I do about 20,000 miles per year and intend to keep the car for quite some time then I guess it would take less than 2 years to pay for the conversion.

Does anybody have any links to companies in or around Essex that do these installations and any links to the garages where LPG garages that supply LPG?

Patrick

[GavinC]

Guess you've been here? http://www.lpga.co.uk/LPGA.htm
and http://www.lpga.co.uk/Contents_f.htm

Appear to be 7 lpg assn. approved installers to choose from in Essex! Spoilt for choice...May be some good prices in that lot.

Best advice I can give is to do your 'homework', shop around and don't DIY. It's a great value fuel. ClassicSwede and Mike Brace appear to be the 'forum resident' respected experts and, I believe, will fit and/or point you in the right direction. Might need direct email contact.