-kleppen zullen verbranden of gebeurt dat nooit bij alfa?
-andere vorm van schade?
-een goedkoop alternatief om probleemloos vele km,s te rijden?
dit wil ik graag eerst ff weten voordat ik overga op LPG of juist niet>>>>
RE: 3.0v6 12v op LPG een goed idee of niet?
Unique Cars and Parts: LPG Autogas fitment to Classic and Veteran Cars
As petrol gets more expensive more people are turning to LPG Autogas and asking such questions as: “I have an old car; can I fit LPG Autogas?”
In answering this question the age of the car is important as is its origin. Australian made cars were designed to run on leaded fuel up until the introduction of emission rules which required the exhaust after treatment by catalysts in 1986. Prior to that date most Australian cars had higher compression ratios and often utilised cast iron cylinder heads without any additional hardening of the valve seat material.
Vehicles with cast iron cylinder heads that have not been upgraded to run on unleaded fuel will show signs of premature valve seat wear when operated on LPG Autogas. Typically this presents in exhaust valves pounding into the cylinder head due to the erosion of the valve seat by cold welding. (Cold welding is the process where at elevated temperatures and high contact pressure, little particles of the valve seat material stick to the valve and gradually erode the valve seat.)
Cold welding has several adverse effects; it slows the heat transfer from the hot valves to the head; it allows the valve to seat unevenly and it closes the valve tappet clearance. Once this process starts it is a sign of imminent failure when the valve actually gets too hot and its material strength is lost resulting in failure of the valve material and effectively “burning out the valves”. The amount of valve recession can be measured by the reduction in clearance between the top of the valve stem and rocker arm or the increasing distance from the base of the cylinder head to the top of the valve stem.
Heat is another enemy of cylinder head durability and this can come from several sources. If the combustion process is too slow i.e. the mixture is so lean of fuel the combustion flame can still be burning as the exhaust valve opens and hence increase the temperature of the exhaust port, valve and manifold. If the engine is not properly tuned, the fuel mixture can be too lean or too rich, or the ignition timing too late or the spark intensity too weak, all these problems can contribute to excessive heat load.
LPG Autogas is referred to as a dry fuel because there is no cooling effect on internal engine components due to vaporisation of the incoming fuel. It is similar to the intake valves of diesel engines where only intake air is drawn in but unlike diesels there is no lubricating effect of the particulates from combustion of the fuel providing lubrication of the exhaust valve seat. In the combustion of Autogas there is a reduction in the production of carbon and fuel additives that provide some lubrication of the exhaust valve seat.
Older imported cars or engines can be more advanced in the emission requirements (e.g. Europe and California) and have switched to different materials to allow for the absence of the lead in the fuel. Most Aluminium alloy heads already have cast iron valve seat inserts (‘Duraloy’ or similar) and sometimes have more exotic materials which are more robust for the elevated combustion temperatures.
As a general rule if the engine is designed for use on petrol motor spirit without a lead additive, it will provide reasonable durability on LPG Autogas.
A word of caution: early engines without feedback control on the fuel system are often retrofitted with LPG Autogas using an “open loop” control system. This is essentially a carburettor system requiring the installer to tune the mixture for the engine requirements to have good start ability and also have the correct air fuel mixture at various operating conditions including maximum power.
Failure to adequately tune for the range of conditions (e.g. power tune on chassis dynamometer) can result in the engine running lean of fuel in some situations. This leads to elevated combustion temperature and excessive heat load on the exhaust valves.
Investing a little more on the installation to include a good quality feedback control system with a computer processing the amount of fuel required is worthwhile. This is achieved by measuring the oxygen concentration in the exhaust gas (a sensor will need to be installed) and varying the amount of fuel added. This minimizes the possibility and subsequent impact of the fuelling system running too lean or too rich.
However, if the LPG Autogas equipment fitted is not able to bring the air fuel ratio of the engine into the required operating range for the computer to control, it will still be a problem. This is why it is important to fit equipment in the form of kits that have been developed and optimised by kit suppliers on a representative vehicle.
Unfortunately kit suppliers concentrate on the latest vehicles and not on developing kits for older model vehicles so if the vehicle to be converted is not an “established” vehicle for conversion it will require a little development by the installer. One way of sorting out the appropriate installer to do the job is to check on his experience by asking “have you converted this type of vehicle before?” and “could I ask the current owner how it is going?”
Sometimes more unusual vehicles have to be the “guinea pig” and all you can do is allow extra time for installation and additional adjustments following the installation. It is important to make sure you still have access to the initial installer and avoid “doctor shopping” since each time a different installer becomes involved he has to repeat the initial investigation at your expense.
There are some vehicles that are known to be problem installations and these are:
• Some Japanese four cylinder engines were known to be soft in the exhaust valve seats.
• Early mechanical petrol injection systems were difficult to isolate to operate a dual fuel system.
• Some vehicles are physically difficult to fit a reasonable sized tank without compromising the luggage space usually small SUV type.
You should expect to use 30% more Autogas than petrol to go the same distance. If you are not using that much Autogas then the air/ fuel ratio of the Autogas option may be running lean of fuel and could affect the durability of the cylinder head.
Occasionally some petrol engines are so inefficient that converting to a close loop control Autogas system improves the combustion efficiency to the extent that the increase in fuel consumption is much less than the 30% but this is really only typical of a petrol carburetted engine on an old car although may occur on some early injection models.
This information is of a non specific nature and should not replace the specific advice of an installer referring to a particular vehicle. To find such installers you should access LPG Australia’s purpose built Autogas web site at www.lpgautogas.com.au
Peter Linahan
Technical Manager – Automotive and Applications
For more information, go to www.lpgautogas.com.au[/b]
As petrol gets more expensive more people are turning to LPG Autogas and asking such questions as: “I have an old car; can I fit LPG Autogas?”
In answering this question the age of the car is important as is its origin. Australian made cars were designed to run on leaded fuel up until the introduction of emission rules which required the exhaust after treatment by catalysts in 1986. Prior to that date most Australian cars had higher compression ratios and often utilised cast iron cylinder heads without any additional hardening of the valve seat material.
Vehicles with cast iron cylinder heads that have not been upgraded to run on unleaded fuel will show signs of premature valve seat wear when operated on LPG Autogas. Typically this presents in exhaust valves pounding into the cylinder head due to the erosion of the valve seat by cold welding. (Cold welding is the process where at elevated temperatures and high contact pressure, little particles of the valve seat material stick to the valve and gradually erode the valve seat.)
Cold welding has several adverse effects; it slows the heat transfer from the hot valves to the head; it allows the valve to seat unevenly and it closes the valve tappet clearance. Once this process starts it is a sign of imminent failure when the valve actually gets too hot and its material strength is lost resulting in failure of the valve material and effectively “burning out the valves”. The amount of valve recession can be measured by the reduction in clearance between the top of the valve stem and rocker arm or the increasing distance from the base of the cylinder head to the top of the valve stem.
Heat is another enemy of cylinder head durability and this can come from several sources. If the combustion process is too slow i.e. the mixture is so lean of fuel the combustion flame can still be burning as the exhaust valve opens and hence increase the temperature of the exhaust port, valve and manifold. If the engine is not properly tuned, the fuel mixture can be too lean or too rich, or the ignition timing too late or the spark intensity too weak, all these problems can contribute to excessive heat load.
LPG Autogas is referred to as a dry fuel because there is no cooling effect on internal engine components due to vaporisation of the incoming fuel. It is similar to the intake valves of diesel engines where only intake air is drawn in but unlike diesels there is no lubricating effect of the particulates from combustion of the fuel providing lubrication of the exhaust valve seat. In the combustion of Autogas there is a reduction in the production of carbon and fuel additives that provide some lubrication of the exhaust valve seat.
Older imported cars or engines can be more advanced in the emission requirements (e.g. Europe and California) and have switched to different materials to allow for the absence of the lead in the fuel. Most Aluminium alloy heads already have cast iron valve seat inserts (‘Duraloy’ or similar) and sometimes have more exotic materials which are more robust for the elevated combustion temperatures.
As a general rule if the engine is designed for use on petrol motor spirit without a lead additive, it will provide reasonable durability on LPG Autogas.
A word of caution: early engines without feedback control on the fuel system are often retrofitted with LPG Autogas using an “open loop” control system. This is essentially a carburettor system requiring the installer to tune the mixture for the engine requirements to have good start ability and also have the correct air fuel mixture at various operating conditions including maximum power.
Failure to adequately tune for the range of conditions (e.g. power tune on chassis dynamometer) can result in the engine running lean of fuel in some situations. This leads to elevated combustion temperature and excessive heat load on the exhaust valves.
Investing a little more on the installation to include a good quality feedback control system with a computer processing the amount of fuel required is worthwhile. This is achieved by measuring the oxygen concentration in the exhaust gas (a sensor will need to be installed) and varying the amount of fuel added. This minimizes the possibility and subsequent impact of the fuelling system running too lean or too rich.
However, if the LPG Autogas equipment fitted is not able to bring the air fuel ratio of the engine into the required operating range for the computer to control, it will still be a problem. This is why it is important to fit equipment in the form of kits that have been developed and optimised by kit suppliers on a representative vehicle.
Unfortunately kit suppliers concentrate on the latest vehicles and not on developing kits for older model vehicles so if the vehicle to be converted is not an “established” vehicle for conversion it will require a little development by the installer. One way of sorting out the appropriate installer to do the job is to check on his experience by asking “have you converted this type of vehicle before?” and “could I ask the current owner how it is going?”
Sometimes more unusual vehicles have to be the “guinea pig” and all you can do is allow extra time for installation and additional adjustments following the installation. It is important to make sure you still have access to the initial installer and avoid “doctor shopping” since each time a different installer becomes involved he has to repeat the initial investigation at your expense.
There are some vehicles that are known to be problem installations and these are:
• Some Japanese four cylinder engines were known to be soft in the exhaust valve seats.
• Early mechanical petrol injection systems were difficult to isolate to operate a dual fuel system.
• Some vehicles are physically difficult to fit a reasonable sized tank without compromising the luggage space usually small SUV type.
You should expect to use 30% more Autogas than petrol to go the same distance. If you are not using that much Autogas then the air/ fuel ratio of the Autogas option may be running lean of fuel and could affect the durability of the cylinder head.
Occasionally some petrol engines are so inefficient that converting to a close loop control Autogas system improves the combustion efficiency to the extent that the increase in fuel consumption is much less than the 30% but this is really only typical of a petrol carburetted engine on an old car although may occur on some early injection models.
This information is of a non specific nature and should not replace the specific advice of an installer referring to a particular vehicle. To find such installers you should access LPG Australia’s purpose built Autogas web site at www.lpgautogas.com.au
Peter Linahan
Technical Manager – Automotive and Applications
For more information, go to www.lpgautogas.com.au[/b]
RE: 3.0v6 12v op LPG een goed idee of niet?
dat is goede info thanks....
inmiddels ook weer bij een gasboer geweest die sterk afraad om een impco installatie te gebruiken hij zegt dat je toch lpi moet toepassen...word erg duur dan
hij zei krijg je een keer backfire met impco dan is de mixer kapot en je lmm ed...dan is er nog het kleppenprobleem...hij zegt als je normaal rijdt dan gaat het wel...(ik rij nooit normaal)
mijn conclusie is er al bijna...op gas moet je koken...niet gebruiken op een 116 gtv6...
of zijn er andere meningen?
RE: 3.0v6 12v op LPG een goed idee of niet?
De conditie van de motor is zeer belangrijk en de V6 is sterk en robuust maar het zijn volgens mij vaak de achterste cilinders die problemen kunnen geven en de motor ernstig wordt beschadigd door plaatselijke oververhitting . Bijv. zelfs een klepzitting van de inlaatklep van de achterste cilinder die loslaat etc.
Oorzaak kan belemmerde koeling zijn door verstopping, verkeerde koelvloeistof of nooit verveste koelvloestof met als gevolg een verteerde koppakking etc.
De V6 is erg geschikt voor LPG,de klepzetels zijn gehard en kop hoeft niet te worden aangepast. Als problemen met de klepzetels zich voordoen, moet dat naar mijn mening een gevolg zijn van plaatselijk oververhitting of te arm mengsel.
Ik ben niet tegen LPG maar de investering in de installatie moet zich terugverdienen en persoonlijk zou ik niet een G3 installatie inbouwen tenzij de motor in prima conditie verkeert. Ik denk dat de meeste problemen met rijden op LPG kan worden voorkomen door goede installateur en goed onderhoud.
Oorzaak kan belemmerde koeling zijn door verstopping, verkeerde koelvloeistof of nooit verveste koelvloestof met als gevolg een verteerde koppakking etc.
De V6 is erg geschikt voor LPG,de klepzetels zijn gehard en kop hoeft niet te worden aangepast. Als problemen met de klepzetels zich voordoen, moet dat naar mijn mening een gevolg zijn van plaatselijk oververhitting of te arm mengsel.
Ik ben niet tegen LPG maar de investering in de installatie moet zich terugverdienen en persoonlijk zou ik niet een G3 installatie inbouwen tenzij de motor in prima conditie verkeert. Ik denk dat de meeste problemen met rijden op LPG kan worden voorkomen door goede installateur en goed onderhoud.
-
frankalfa
- Guru Quintuplo
- Berichten: 8048
- Lid geworden op: ma dec 27, 2004 20:34
- Locatie: Koewacht (of all places!)
Re: RE: 3.0v6 12v op LPG een goed idee of niet?
Beste conclusie ever!!!!!!
dat is goede info thanks....
inmiddels ook weer bij een gasboer geweest die sterk afraad om een impco installatie te gebruiken hij zegt dat je toch lpi moet toepassen...word erg duur dan
hij zei krijg je een keer backfire met impco dan is de mixer kapot en je lmm ed...dan is er nog het kleppenprobleem...hij zegt als je normaal rijdt dan gaat het wel...(ik rij nooit normaal)
mijn conclusie is er al bijna...op gas moet je koken...niet gebruiken op een 116 gtv6...
of zijn er andere meningen?
Koop er iets bij om veel kms te maken (ax diesel schijnt zuinig te lopen...) 
Grtz,fRank
Poetsen is voor mensen met patina-angst...
Re: RE: 3.0v6 12v op LPG een goed idee of niet?
Daar kun je beveiligingen voor inbouwen dat als er een backfire optreedt de overdruk kan ontsnappen op een nette manier, is ook gedaan bij mijn 164 V6 12v op lpg.
hij zei krijg je een keer backfire met impco dan is de mixer kapot en je lmm ed...dan is er nog het kleppenprobleem...hij zegt als je normaal rijdt dan gaat het wel...(ik rij nooit normaal)
-
ravado
- Guru Triplo
- Berichten: 3900
- Lid geworden op: ma dec 27, 2004 07:04
- Locatie: home is where you dig it
RE: 3.0v6 12v op LPG een goed idee of niet?
koop een diesel......
lpg is goed....koop.......
maar regelmatig 6500 toeren draaien is vragen om problemen...... tenzij je beide koppen laat aanpassen voor lpg....
koken doe je op gas......
goedkoop rijden doe je op Lpg....
stinkend, nagelend, rokend en een filter in je buis hebbend rijden doe je op diesel....
lpg is goed....koop.......
maar regelmatig 6500 toeren draaien is vragen om problemen...... tenzij je beide koppen laat aanpassen voor lpg....
koken doe je op gas......
goedkoop rijden doe je op Lpg....
stinkend, nagelend, rokend en een filter in je buis hebbend rijden doe je op diesel....
Gtv-6 3.0V6 heel langzaam in opbouw...met de nadruk op heel langzaam