To LPG or not to LPg

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
So where does all this proof come from ? How have you concluded the mixtures are weak ?
Yes I am saying that the heater hoses are more likely to leak when tee'd into for heating a vaporiser - because its true.Pressurize a cooling system when cold and you will see what I mean,my record so far is 7 separate leaks on one car - none of which was visible when hot,but produced a small drip when cold.Couple that to most owners not feeling the need to open the bonnet between services and you can work out what will happen.
The fact remains that ANY 94mm Rover v8 will suffer if allowed to overheat or run excessively lean mixtures under high load conditions.
Are you familiar with the 3.5 Disco's that ran 14Cux EFI,either open or closed loop ? The same system that late 3.9 RR classics,later D1's ran - the same blame of weak fuel maps.Funny how the 3.5's never had a slipped liner,even when abused beyond belief with poor/no servicing and a cooker ring system.
A customer and friend of mine pulled up at my workshop one day with his 2 door RR,when he switched it off we could hear the oil boiling in the sump it was so hot.There was no coolant at all in that engine,(he had upset someone and they had drained it for him)so we let it cool over night.Next morning we refilled it and changed the oil.I thought it was toast,not so - it had no ill effects at all,the engine still runs today,that was at least 12yrs ago.this is just one example of how tolerant the 87.5mm bore engine is compared to the 94mm.What methods do you use to ensure correct mixture in your lpg setups ?
 
eightinavee said:
So where does all this proof come from ? How have you concluded the mixtures are weak ?
Yes I am saying that the heater hoses are more likely to leak when tee'd into for heating a vaporiser - because its true.Pressurize a cooling system when cold and you will see what I mean,my record so far is 7 separate leaks on one car - none of which was visible when hot,but produced a small drip when cold.Couple that to most owners not feeling the need to open the bonnet between services and you can work out what will happen.
The fact remains that ANY 94mm Rover v8 will suffer if allowed to overheat or run excessively lean mixtures under high load conditions.
Are you familiar with the 3.5 Disco's that ran 14Cux EFI,either open or closed loop ? The same system that late 3.9 RR classics,later D1's ran - the same blame of weak fuel maps.Funny how the 3.5's never had a slipped liner,even when abused beyond belief with poor/no servicing and a cooker ring system.
A customer and friend of mine pulled up at my workshop one day with his 2 door RR,when he switched it off we could hear the oil boiling in the sump it was so hot.There was no coolant at all in that engine,(he had upset someone and they had drained it for him)so we let it cool over night.Next morning we refilled it and changed the oil.I thought it was toast,not so - it had no ill effects at all,the engine still runs today,that was at least 12yrs ago.this is just one example of how tolerant the 87.5mm bore engine is compared to the 94mm.What methods do you use to ensure correct mixture in your lpg setups ?
Click to expand...

was going to ask a question but I'll wait until you two stop, Ah yev stopped, good.

Right sees yer all gemed up, what is the estimated recovery of costs on these systems and maintenance with cost of consumables, and availability of qualified repair centres.
 
The amount of high speed detonation that occours with the later engines is a fairly big clue the maps are weak. This was what lead the specialist manufacturers to invest in their own fueling strategies. The 3.5 14CUX system was running the same map as the LE jetronic flapper system. (they are bascialy the same system, but the AFM was changed).

What TVR found was detonation was occouring, this was losening the liners over time, this put undue stress on the support, result dropped liner. That the 3.5 is stronger in this area is irrelavent, as with a propper map the mixture would not be so lean, the detonation would not take place and the liners wodul not work loose.

Funny you should mention the 3.5 my last RR was a 3.5 efi that had blown its head gaskets, ands my SD1 on carbs has suffered the same.

As for setting the systems up.. with the non closed loop ones in the past I used a DGA 1800. With the lambda controled systems Just let them get on with it (always with a new probe). Must have done somthing right.. never had a blowback, and not killed any engines even the 10.5:1 P5

Stewart
 
Got no idea,I just fix them or tell garages what is wrong with them.And as for qualified repair centres,well thats nearly funny - I just wish there were.
 
eightinavee said:
Got no idea,I just fix them or tell garages what is wrong with them.And as for qualified repair centres,well thats nearly funny - I just wish there were.
Click to expand...

So throw the gas and injection to fook and fit a holly and enjoy the sound or buy a diesel, coz it's a big engine it's gona drink fuel and either you can afford it or you can't, and most can't.
 
Too right unfortunatly. Mind you are there any for standard cars? Don't know, never used one always done my own ever scince some MOT con man tried to tell me I needed a new rack on My '59 Austin A40, not the sort of thing you say to a CAA certified aircraft engineer...

Stewart
 
Zaphod said:
The amount of high speed detonation that occours with the later engines is a fairly big clue the maps are weak. This was what lead the specialist manufacturers to invest in their own fueling strategies. The 3.5 14CUX system was running the same map as the LE jetronic flapper system. (they are bascialy the same system, but the AFM was changed).

What TVR found was detonation was occouring, this was losening the liners over time, this put undue stress on the support, result dropped liner. That the 3.5 is stronger in this area is irrelavent, as with a propper map the mixture would not be so lean, the detonation would not take place and the liners wodul not work loose.

Funny you should mention the 3.5 my last RR was a 3.5 efi that had blown its head gaskets, ands my SD1 on carbs has suffered the same.

As for setting the systems up.. with the non closed loop ones in the past I used a DGA 1800. With the lambda controled systems Just let them get on with it (always with a new probe). Must have done somthing right.. never had a blowback, and not killed any engines even the 10.5:1 P5

Stewart
Click to expand...
Load of rubbish,had you not noticed that Gems and Motronic both run a pair of knock sensors ? If you had ever taken the time to scope the oxygen sensors of an Lp petrol engine on Gems or Motronic you would have realised the willingness of either to widen the injector pulse width to give a rich signal from the oxy sensor to the ecu.(Without UEGO's you cannot tell how far from Lamda the mixture is - less a small deviation either way)Narrow band sensors seem to manage fuelling on 99% of other closed loop engines,so why do Rover V8's suffer ? Do you not think they tried to get decent fuel economy out of other models too ?
The truth is there is a weakness in the block - caused by taking out the bore size too large and not doing anything to improve liner support or give the head gasket fire rings something to seal against.
Your "let them get on with it" comment says it all - you had no idea what was going on - just trust a new,(untested) component take the work on,or take the flak if it goes wrong.Ever wondered why your RR and SD1 blew head gaskets ?
 
Hmm.. you have just shown you have no understanding of what the knock sensors are there for. The problem is the system uses these to attempt to run on the weakest mixture it can possibly get away with, as close as possible to knocking as possible.. unfortunatly this is rather too close, If you are going to run that close to CI then you need to strengthen a LOT. I do not dipute the 3.5 is stronger in respect to the liners shifting but maintain the later blocks would be fine if the fueling was not so close to the edge.

I do let the modern feedback sytsems get on with it now, although on the first one I did try and do better and fiddle with it and while it worked leaving it alone worked just as well so it was pretty pointless. I have only converted my own cars, never any others although have had more than a few to fix.

I have no idea what cased the HG's to fail on my RR and SD1, but I do know what it wasn't.. as the SD1's head gaskets went in 1982, 23 years before I saw it!, althoug the RR gaskets went a month before I bought it, Neither have had LPG, but the SD1 will have

Stewart
 
Ok, so now you know more than the manufacturers - of course I know what knock sensors do and what they achieve.If ignition advance close to dieseling is not desirable then why do all the manufacturers use it ? Its also not to do with fuel mixture,just ignition advance,the oxygen sensors used on Gems,(Titania) and Motronic,(Zirconia) are narrow band and can only indicate a small shift either side of Lambda.So when running closed loop under cruise conditions,(Where the misplaced blame lies) the mixture wont be much higher than 14.7/1 - so the ecu has the oppertunity to advance up the ignition to up output.
If you ever got to scope all this you would realise what its trying to do.
It is a design fault of the engine - NOT the EFI system.
 
I have a multi point Prins LPG system fitted to my V8 Vouge Thor engine. I have had no problems in the last 2 years it has been fitted, only that the spark plugs need changing more often.
When its only doing about 13 mpg, it has saved me alot of cash!
 
eightinavee said:
Ok, so now you know more than the manufacturers - of course I know what knock sensors do and what they achieve.If ignition advance close to dieseling is not desirable then why do all the manufacturers use it ? Its also not to do with fuel mixture,just ignition advance,the oxygen sensors used on Gems,(Titania) and Motronic,(Zirconia) are narrow band and can only indicate a small shift either side of Lambda.So when running closed loop under cruise conditions,(Where the misplaced blame lies) the mixture wont be much higher than 14.7/1 - so the ecu has the oppertunity to advance up the ignition to up output.
If you ever got to scope all this you would realise what its trying to do.
It is a design fault of the engine - NOT the EFI system.
Click to expand...

I know exactly what its trying to do, but what you can't see is the damage it does to the rest of the engine. If you had not noticed HGF is more common on modern engines than it ever used to be, and its this daft obsession with the ultimate fuel economy(required to offset the weight of the modern car with all its safety rubbish) resulting in stupidly high combustion temps causing it. If the standard systems are so good why do identical engines not fitted with it not suffer this problem? The 'weaker' blocks are fine when not subjected to this fuelling abuse. If they had run stoic the problem would not have occoured. Although the problems casued by the weak mixture don't do the spare parts sales any harm

Joe Turley said the design was safe to 4.4 litres (And I supect he knew more that thing or two about it), the P76 engine of that capacity running carbs did not suffer these problems, and much of the 4.4 litre engine found its way to the 3.9/4.2 quiet why Rover never used the 4.4 version I am not sure but I suspect it was only because it was a Leyland Austrailia product.

Stewart
 
i have a tartarini multi point system and thankfully it was fitted already when i brought the vehicle so i didnt have to worry about it paying for its self :)
 
I have a prins vsi system professionally fitted by the previous owner at a cost of £2500 the install is very neat and the car runs perfectly on gas i can't really tell any difference!
 
redrange said:
i have a tartarini multi point system and thankfully it was fitted already when i brought the vehicle so i didnt have to worry about it paying for its self :)
Click to expand...

If thats the eTAgas sytem they did (CIS multipoint system), it does work well but the fuel distributors (the bits with all the pipes going in) can suffer from heavy ends over time, and its wise to give them a squirt of carb cleaner once in a while. The SGi system does not suffer this

Stewart
 
Zaphod said:
I know exactly what its trying to do, but what you can't see is the damage it does to the rest of the engine. If you had not noticed HGF is more common on modern engines than it ever used to be, and its this daft obsession with the ultimate fuel economy(required to offset the weight of the modern car with all its safety rubbish) resulting in stupidly high combustion temps causing it. If the standard systems are so good why do identical engines not fitted with it not suffer this problem? The 'weaker' blocks are fine when not subjected to this fuelling abuse. If they had run stoic the problem would not have occoured. Although the problems casued by the weak mixture don't do the spare parts sales any harm

Joe Turley said the design was safe to 4.4 litres (And I supect he knew more that thing or two about it), the P76 engine of that capacity running carbs did not suffer these problems, and much of the 4.4 litre engine found its way to the 3.9/4.2 quiet why Rover never used the 4.4 version I am not sure but I suspect it was only because it was a Leyland Austrailia product.

Stewart
Click to expand...
You are not helping yourself now - all the 94mm bore Rovers have had liner problems wether badged 3.9,4.0,4.2 or 4.6 - all were injected - with 3 different systems.The early 3.9's were open loop in the uk market and all have been sold open loop in certain markets.
Have you ever watched a Rover v8's oxygen sensors in live data whilst a car is being driven ? If you had you wouldnt keep banging on about lean fuel maps.
And to go on about JRA's 4.4 version of the Rover used in the P76,(Usually known as the P38 as it was only half the car it should have been.)and the Leland Terrier truck.It got to that capacity by stroking,the bore remained at 87.5mm.So there was plenty of metal to support the liners.Also helped by the fact that the block was taller.
 
Zaphod said:
If thats the eTAgas sytem they did (CIS multipoint system), it does work well but the fuel distributors (the bits with all the pipes going in) can suffer from heavy ends over time, and its wise to give them a squirt of carb cleaner once in a while. The SGi system does not suffer this

Stewart
Click to expand...
and all this knowledge coming from a bloke who doesn't know when the v.c is stuffed on his car :confused: :confused: :confused: .
i certainly know whos advice i would follow :rolleyes: :) .
rick.
 
eightinavee said:
You are not helping yourself now - all the 94mm bore Rovers have had liner problems wether badged 3.9,4.0,4.2 or 4.6 - all were injected - with 3 different systems.The early 3.9's were open loop in the uk market and all have been sold open loop in certain markets.
Have you ever watched a Rover v8's oxygen sensors in live data whilst a car is being driven ? If you had you wouldnt keep banging on about lean fuel maps.
And to go on about JRA's 4.4 version of the Rover used in the P76,(Usually known as the P38 as it was only half the car it should have been.)and the Leland Terrier truck.It got to that capacity by stroking,the bore remained at 87.5mm.So there was plenty of metal to support the liners.Also helped by the fact that the block was taller.
Click to expand...

Well you are in minoirty of one on the cause of the liner problmes on th bigger engines.

From RPi's website..
'Overheating starts with water loss. The early 3.9 and 4.2 (pre '95-'96) engines were basically an over-bored 3.5 casting with 4mm extra on the diameter of the liners. This caused a reduced thickness of aluminium between the water jacket and the cylinder bore. The subsequent water loss problem normally starts off as just a water light that appears once a month or so, then once a week, until it becomes a permanent feature. The normal unsuspecting owner will have by this time paid for heads to be skimmed and gaskets to be changed, and they will have spent a lot of money already. So, although the engine functions fine, it is a permanent worry leading towards a total engine failure.
Many might be excused for thinking that the overheating is caused by running the engine in a hot climate, or with a radiator problem, or even insufficient cooling fans or oil cooler, but we can assure you this is not normally the case.
3.9 & 4.2 The true & main reason these engines run very hot is due to the fuel/air ratio, or fuel mixture, that is controlled by the engine EFi computer (ECU Chip) from the factory. This was designed to run very lean through the mid range to make altitude driving or mid range emissions (tested in some countries) less of a problem, the upshot of this however is that when these engines are used on low quality or low octane fuels, or when the engines are upgraded with items even as minor as a free-flow air filter or exhaust headers & Cam/Head upgrades, although all of these are only mild upgrades, they will make a weak engine run even weaker and the problem will get closer!
The solution is simple (if it's not cracked already), fitting our Optimax or Tornado Eprom (ECU Chip) will give your engine the near perfect fuel/air ratio it deserves, thus giving lower engine internal temperatures and giving, without other modifications to all, 15% efficiency boost [power and economy} & also allow the upgrades you have already done to be beneficial at last, instead of being detrimental.'

Stewart
 
rick071155 said:
and all this knowledge coming from a bloke who doesn't know when the v.c is stuffed on his car :confused: :confused: :confused: .
i certainly know whos advice i would follow :rolleyes: :) .
rick.
Click to expand...

Hmm I must rember if I don't know about VC's I must know nothing about engines.. yes makes a lot sence as both must use similar construction methods.

Stewart
 
Are you a politician ? Seems you are unable to give a straight answer to a question,then quote the usual dribble that you trawled up off the net.Do you not realise the reputation of RPI,they sell chips.And the funny thing is they will not warrant the engine against liner issues,"the damage had already been done"
The last car that came to me after going to them was running on 6cyls after they had serviced it,put some posh leads on it and charged several hundred pounds.The engine had very little compression on the misfiring cyls and needed stripping to find the cause.It had apparently come out of RPI like that,the owner had zero mechanical knowledge.
Btw it would be alot easier to change your viscous coupling and keep the advanages of the BW box,if you do that I would also advise that you pull out the rear output shaft and inspect the splines for wear.But then I'm sure you already knew that.
 
You must log in or register to reply here.

Similar threads

awkwardbob
P38A Is it time to jump to LPG ? (4.6l Gems)
4 5 6
Replies
114
Views
9K
awkwardbob
awkwardbob
Montyjohn
Fitting a second hand LPG kit. What do I need to know?
Replies
11
Views
1K
norseman
norseman
xDParis64
Freelander 1 Converting from wasted spark to distributor (or Visa Versa)
Replies
0
Views
359
xDParis64
xDParis64
new to all this
ATF change… or not?
Replies
9
Views
1K
new to all this
new to all this
Irish4x4
To buy or not to buy - Land Rover Defender Td5 2004
Replies
13
Views
2K
Irish4x4
Irish4x4
Back
Top