Spark plugs and LPG

[thatfatbloke]

I may have asked this before, but can't find the post. Do I need 'ordinary' spark plugs when running LPG?. I notice on Fleabay a seller knocking out Bosch Super Plus for £16 for all eight plugs, whereas Denso iridium come in anywhere between £40-£80.

[ColinBarber]

10 minutes ago, thatfatbloke said:

I notice on Fleabay a seller knocking out Bosch Super Plus for £16 for all eight plugs, whereas Denso Iridium come in anywhere between £40-£80.

You get what you pay for. There are a lot of fakes on eBay, including Denso so be careful.

[steve2006]

I bought a set of NGK iridiums for mine for around £45.00 some time ago but when I came to fit them I only managed to remove one HT lead from one plug, even though they were replaced a few years ago and were lubricated with the grease provided with the lead set they are now firmly stuck to the plugs.

I didn’t want to risk tugging them so hard I damaged or broke the leads, if anyone has a safe removal method they could recommend I am all ears.

[Malc]

is it now that plugs have a 60k or maybe 100k miles lifespan and the age they are in situ, that makes them challenging to remove do you think ?  everything seizes-up !

In olden times when plugs were changed every 12k miles or at each main service, and when a set of plugs cost about £2/10/6d, that it was an easy job to do .

Just reflecting a little I'm afraid

Malc

maybe there's something to be said for just loosening and pushing back home, the plug leads, every year or so 

[sorcerer]

When we had our LPG RX300 I used NGK Laser Line LPG plugs and found them to be excellent - bit of info here:

 

LPG_info.pdf

[messi]

Please guys don't fall "lpg plugs" rubbish. It's all a con. Just use normal denso or Ngk irridum sparkplugs 

[Tinonline]

Cars were fitted with either Denso or NGK I say that as my ls400 at 72k Miles had shot ngk’s with no evidence of plug changes in its Lexus service history. I got my Densos in a sale at Opie Oils. Good value and fit for tons of miles.

[usuf_x]

If it helps....I had a MK1 Lexus gs300 sport and  w210 Mercedes  E Class  both on LPG and in the 13 years of ownership swapped them over with regular plugs from ECP (good quality ones) never had issues...though I never brought online worried about fakes...

[MLW]

Mine will need doing at 60,000 miles. Denso original from ECP. Probably about £88. Not bad for 6 years.

[sorcerer]

8 hours ago, messi said:

Please guys don't fall "lpg plugs" rubbish. It's all a con. Just use normal denso or Ngk irridum sparkplugs 

There's no doubting and no denying that the combustion of Propane, and the products of that combustion, are different from that of petrol so why is it so difficult for people to understand that spark plugs are different too?

Yes, of course, any old spark will ignite the fuel but to get the best from it and to get the longest life from the plugs, a product that has been designed around those parameters is best.

[ColinBarber]

7 hours ago, sorcerer said:

There's no doubting and no denying that the combustion of Propane, and the products of that combustion, are different from that of petrol so why is it so difficult for people to understand that spark plugs are different too?

Yes, of course, any old spark will ignite the fuel but to get the best from it and to get the longest life from the plugs, a product that has been designed around those parameters is best.

It is obviously a compromise as you need both petrol and LPG to work. No point getting great LPG plugs that don't work well when running on petrol.

iridium plugs can typically stand up to use of LPG fine, so no need to swap them out. They just may not last the 60k/100k life they would when just being used with petrol.

[sorcerer]

34 minutes ago, ColinBarber said:

It is obviously a compromise as you need both petrol and LPG to work. No point getting great LPG plugs that don't work well when running on petrol.

But surely, that's the whole point - an 'LPG plug' has been designed with both fuels in mind but an 'ordinary' plug hasn't. 

As long as there's no great difference in price (which there wasn't when I last bought the Laser Lines) and the 'LPG plugs' aren't a rip-off, I'd go with them every time.

[ColinBarber]

1 hour ago, sorcerer said:

But surely, that's the whole point - an 'LPG plug' has been designed with both fuels in mind but an 'ordinary' plug hasn't. 

As long as there's no great difference in price (which there wasn't when I last bought the Laser Lines) and the 'LPG plugs' aren't a rip-off, I'd go with them every time.

That's fair enough, but if your plugs don't need changing and you have an LPG conversion then I wouldn't recommend changing them because you need LPG plugs.

[sorcerer]

55 minutes ago, ColinBarber said:

That's fair enough, but if your plugs don't need changing and you have an LPG conversion then I wouldn't recommend changing them because you need LPG plugs.

Oh I completely agree with you there Colin, no need to change 'mid-term' as it were, but when they're ready to change I'd always then go for the LPG plugs.

[ls400lpg]

Yes. 

 

Just use normal Denso OEM spark plugs for £30 on eBay. Had spark plugs on my MK3 lpg and after 100,000 miles the mechanic said  do not change the spark plugs as there are nearly new!!!!

 

Honestly

[Bluesman]

The reason why the normal plugs last without change is because LPG doesn't burn as hot as petrol so it's much kinder to your plugs.

 

[ls400lpg]

Hi Bluesman

I wanted my MK4 converted to LPG. Was thinking Profess gas but heard mixed reviews. Could you enlighten me on your experience.

[dendonc]

6 hours ago, ColinBarber said:

....................

I had an LPG conversion on my last LS400, it justs uses ordinary pugs, see the autogas site

http://www.go-lpg.co.uk/AboutLPG.html

[sorcerer]

1 hour ago, ls400lpg said:

I wanted my MK4 converted to LPG. Was thinking Profess gas but heard mixed reviews. Could you enlighten me on your experience.

Contact me off the forum by email to jhewitt1958@gmail.com and I may be able to help with some information.

I have no experience of Profess Gas but one important thing to take into account is that they only install one brand of system and that is STAG. They may be the best, quickest, tidiest installers in the world for all I know, but is STAG the best system for your car?

Many, many moons ago when I wanted my first car converted, the world of LPG was a complete minefield. Not only did you need a good, reputable fitter, but you also needed to know that they would be able to match the LPG system to the car. I personally found that I had a brilliant, well-respected installer in my own town, but he was only qualified to install a couple of systems, neither of which he could guarantee would perform flawlessly on my car.

One thing that often happens when the LPG system and the car are incompatible or mismatched in some way is that, under heavy load, just when you want it to be drinking cheap gas rather than expensive petrol, the gas system can't deliver enough power and it starts to inject petrol as well as gas to cope with the demand - but it doesn't give you, the driver, any indication that it's doing this.

It took me a good SIX MONTHS of research before I was confident in handing over my hard-earned cash to an installer who I was confident would do a really neat, safe job of installing a system that would be more than up to the job, and I ended up travelling about 60 miles to have it done.

In those early days an installer would fit a complete system, after buying a complete kit of parts from the manufacturer and it either would, or it wouldn't be suitable for any given car. Nowadays, it's much easier for installers. Of course, they have to be really on the ball and know their stuff inside out but as long as they do, they can mix and match components to get bespoke systems to make sure they get the absolute best for any given car (say, for example, using a KME NEVO ECU with an OMVL reducer and MagicJET injectors) rather than just sticking to one system from one manufacturer.

[ColinBarber]

4 hours ago, Bluesman said:

The reason why the normal plugs last without change is because LPG doesn't burn as hot as petrol so it's much kinder to your plugs.

 

This isn't really true. Heat is released more quickly so cylinder head temperatures are higher with LPG compared to Petrol, hence why plugs don't last as long, especially non-iridium ones.

 

[dendonc]

48 minutes ago, sorcerer said:

they only install one brand of system and that is STAG. They may be the best, quickest, tidiest installers in the world for all I know, but is STAG the best system for your car?

No idea if it's ''the best'' & less idea of how that would be defined, all profess instillations staff are sent to poland to stags to be trained, Ive never heard any 'failings'related to their system, I could never detect any any difference whatsoever between the petrol & gas.

There are lot of problems (or were) a lot of problems with so called 'instillation specialists', especially in London.

[dendonc]

 

Quote

The reason why the normal plugs last without change is because LPG doesn't burn as hot as petrol so it's much kinder to your plugs.

Before the LPG system kicks in the car has to run on petrol until the temprature builds up, then the LPG system just kicks in.

[sorcerer]

2 hours ago, dendonc said:

No idea if it's ''the best'' & less idea of how that would be defined, 

Well that's sort of the point I'm making. We, as the users, don't know and we rely on the experts to inform and guide us to the best choice for our cars and circumstances, but if Profess only have knowledge of one system, how can they do that?

If you've only ever had Watney's Red Barrel, you can't advise others how good Old Speckled Hen is; if you've only ever driven a Fiat Punto, you can't advise others how good a Lexus is - and if you only fit one brand of LPG system, how can you say that it's the best in any situation for any car?

[dendonc]

57 minutes ago, sorcerer said:

but if Profess only have knowledge of one system, how can they do that?

Ive never heard of anyone from profess saying theirs was the best, what did they say to you to that effect? 

57 minutes ago, sorcerer said:

We, as the users, don't know and we rely on the experts to inform and guide us to the best choice for our cars and circumstances

Yes thats why I went to profess, the feedback from LS owners on this forum was top rate for profess as in fact it was from the AA when the guy saw it & compared the fitting he'd seen on other conversions, same with my indi when he changed the starter motor & had to take maniifold off.

As for me, I had 100% perfect running from it from when I got the conversion in 2012 to Feb this year when I changed cars = appx 40k trouble free miles.

Out of interest, what probs have you had or heard of with the stag system, sound like you've had a terrible ordeal, I mean probs apart from maybe those fitted by 'cowboys'? I'm not even sure they sell to anyone who has not got a Stag trained workforce.

[ls400lpg]

Are they still doing £1000 all in