Spark Plugs - Best Ones To Use

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smokie1010
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Spark Plugs - Best Ones To Use

#1 Post by smokie1010 » Tue Nov 24, 2015 4:40 pm

I have a 2006 Astra with the 1.6 Z16XEP Twinport Engine. I normally use Genuine GM34 Plugs which are actually Bosch FQR8LEU2 plugs but in GM boxes. Although Vauxhall state to change them every 4 years or 40k miles I always change them every 10k miles.

I have been looking around various posts on here and some seem to recommend using NGK plugs, the standard NGK plugs and not to bother with the specific LPG ones.

Just wondering what people think is the best plugs to use.

Thanks

Gilbertd
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Re: Spark Plugs - Best Ones To Use

#2 Post by Gilbertd » Tue Nov 24, 2015 5:25 pm

In order of preference after many years and many different cars and motorcycles, NGK, Bosch, anything else you've heard of, supermarket own brand, anything else you haven't heard of, unbranded Chinese knock offs, Champion. When I used to race motorcycles the standing joke was if you wanted to enter the 4 stroke championship but had a 2 stroke bike, you just fitted Champion plugs and it would only ever fire every other time you wanted it to......

If you are changing plugs every 10k, don't bother with the overpriced LPG plugs or even Iridium, just fit the standard ones for the engine which, according the www.sparkplus.co.uk, would be NGK ZFR5F.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

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Re: Spark Plugs - Best Ones To Use

#3 Post by Tubbs » Tue Nov 24, 2015 5:36 pm

The NGK plugs are very good on this engine.

smokie1010
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Re: Spark Plugs - Best Ones To Use

#4 Post by smokie1010 » Tue Nov 24, 2015 6:27 pm

Thanks for the replies, NGK it is then. According to the NGK website they should be gapped at 0.9mm.

Bizarre thing is the Haynes Manual says the they should be set at 1.3mm and Autodata says 0.9mm the same as NGK, apparently Vauxhall quote 1.3mm. I will gap them at 0.9mm as suggested by NGK unless it should be different for LPG.
.

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Re: Spark Plugs - Best Ones To Use

#5 Post by Gilbertd » Tue Nov 24, 2015 8:40 pm

Normally the only thing you might consider changing when running on LPG is to gap the plugs down from whatever the normal setting is down to 0.9mm. So that should be spot on. 1.3mm seems awfully wide even for running on petrol.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.

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Re: Spark Plugs - Best Ones To Use

#6 Post by Tubbs » Wed Nov 25, 2015 11:09 am

God ! That's ford spec lol.
As I have said before I'm sure ;) it's all about spark 'dwell' with modern engines. If the Ecu doesn't see dwell it can cause issues. But .8-.9 seems to keep the cars management system happy.

robertXX
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Re: Spark Plugs - Best Ones To Use

#7 Post by robertXX » Sun Nov 29, 2015 9:36 am

yup i run ngk bp8es on my astra@12psi boost max , and always use standard type ngk in all my vehicles .(apart from medusa cos i couldn't afford a set )

Gilbertd
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Re: Spark Plugs - Best Ones To Use

#8 Post by Gilbertd » Sun Nov 29, 2015 6:25 pm

Aw c'mon, my local motor factors only charge £1.99 a go for standard NGK plugs. That's only 24 quid.......
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.

oz striker
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Re: Spark Plugs - Best Ones To Use

#9 Post by oz striker » Sun Nov 29, 2015 10:50 pm

Does anyone buy or any installs actually need those special LPG plugs (silver arent they?). I heard they were a waste of time.

TNT
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Re: Spark Plugs - Best Ones To Use

#10 Post by TNT » Sun Nov 29, 2015 11:58 pm

My car hated NGK lpg plugs. Other cars I don't know.

Unless your running an old carbureted engine, stick with the standard plugs that work with your engine. Maybe change them more often. Some cars specify expensive plugs anyway, like bmw/mini's.

Gilbertd
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Re: Spark Plugs - Best Ones To Use

#11 Post by Gilbertd » Mon Nov 30, 2015 8:39 am

oz striker wrote:Does anyone buy or any installs actually need those special LPG plugs (silver arent they?). I heard they were a waste of time.
Thr Brisk ones are silver and most people that have fitted them have removed them to cure the misfires they induced. The NGK ones are Iridium so will last longer but so will the normal NGK Iridium ones that are about a third of the price. For my Range Rover the standard NGK plugs are £1.99 each and need to be changed every 10,000 miles, the Iridium equivalents are around £5.00 each and will last for around 40,000 miles, the NGK LPG plugs cost about £15.00 each and last around 40,000 miles, you work it out.....
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.

LPGC
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Re: Spark Plugs - Best Ones To Use

#12 Post by LPGC » Mon Nov 30, 2015 1:54 pm

Agreed with much of what has already been said.

LPG specific / Brisk plugs often give poor results, fitting multi electrode plugs on engines where standard plug has single electrode often gives poor results.

Standard plugs often work well, el-cheapo NGK single electrode nickel plugs often work well and can give the best quality spark and results, a longer lasting option that usually gives good results are NGK iridium plugs. Not for every model engine, though.

Difficult to generalise because there will be lots of exceptions, e.g. single electrode NGK nickel plugs don't seem to give good results on the older (early 2000's) Vauxhall engines where the standard twin electrode Bosch plugs seem to work best. Plugs have a lot of properties besides the usual considered aspects (physical dimensions and heat range), iridium plugs are not always available that match all properties (besides the obvious electrode material) of standard plugs.

Swapping plugs from a known good performer to one of experimentation can depend on point of view...

Good idea to change plugs from type already fitted which are known to work well to a different longer lasting type that may be a bit dearer and may or may not work well, in order to potentially save work in future, at risk of wasting money and causing extra work now? The point of long lasting plugs is to save work changing them, long lasting plugs seldom save money over multiple sets of el-cheapo plugs. It would be a shame to gamble on buying and fitting long lasting plugs which may or may not work as well as those being removed, only having to immediately replace them straight away with standard or el-cheapo plugsm, because then you've wasted money on plugs you can't return and wasted the time you hoped to save in future immediately! Suppose you've done 20K without problem on standard platinum plugs which are a real pain to change on your engine, would you feel more confident fitting the same plug again or replacing them with iridium plugs? After 20k the platinums you removed may have a fair bit of noticeable wear, after 20k iridiums might be expected to have a bit less wear, but you know the platinums didn't cause misfires even with that wear, you don't know if platinums will cause misfires with less wear.

If a bit of oil is noticed in plug holes on deep plug engines (fairly common), is it worth fitting plugs which may or may not give good results when it would in any case be a good idea to remove coils to see down plug holes during servicing (not much of a money or time saver)? Could make the same point about checking for corrosion on plug tops, plug clips on coil packs, the springs in them, about removing plugs to check condition, running a compression check, etc. In this case, if platinum or iridium are fitted and easy to access, it may be a good idea to try el-cheapo plugs as you'll be getting down to access plugs during next service anyway and in some cases nickel plugs with wide centre electrode can give best results of all.

On engines where plugs are a bit difficult to change, many owners might consider it better to try iridiums but when plugs are extremely difficult to change, unless person has free time available now they may think it better to fit same plugs as removed, avoiding risk of needing to immediately repeat changing plugs and wasting money. If plugs are easy to change, why not try nickel plugs, change more often but you get to do what used to be considered routine checks more routinely, not a bad thing, and plug electrical connection will always be shiny etc!

Simon
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Tubbs
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Re: Spark Plugs - Best Ones To Use

#13 Post by Tubbs » Wed Dec 02, 2015 7:15 pm

I had a hilarious one on my Skoda.
Plug 1 accessible without manifold removal NGK.
Plug 4 also accessible was Bosch.
When I took the manifold off ? 2+3 ? Volkswagen !
130k. But it did have a misfire, that's why I changed the plugs lol.

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Re: Spark Plugs - Best Ones To Use

#14 Post by Gilbertd » Wed Dec 02, 2015 11:00 pm

Were they all the correct length though? My mate in France bought a boat with a pair of Volvo 4 cylinder motors in it (marinised version of the old 200 series 2 litre B20 engine). Didn't run too badly but we felt it would benefit from a service. Not only did we find about 6 different makes out of the 8, there were 3 different lengths! It should have had long reach plugs but some were short reach and one was the very short reach. I'm surprised that pot fired at all with the spark lurking an inch out of the combustion chamber up inside the plug thread. Had to run a tap down the plugholes to clean the threads out.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.

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Re: Spark Plugs - Best Ones To Use

#15 Post by Tubbs » Thu Dec 03, 2015 12:06 am

God ! I bet you did Richard ! It's amazing how shit an engine has to be to actually stop running properly. Like truly off its swede !

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Re: Spark Plugs - Best Ones To Use

#16 Post by LPGC » Thu Dec 03, 2015 11:26 am

Gilbertd wrote:My mate in France bought a boat with a pair of Volvo 4 cylinder motors in it (marinised version of the old 200 series 2 litre B20 engine)
Prime candidate for an LPG install? :)

On my current old Grand Voyager with transverse V6 the rear 3 plugs are difficult to access, can just about get them out working from underneath using a different combination of tools for each plug, just about as easy to change plugs by removing the wiper mechanism and top half of inlet manifold as it is to change them working from underneath. Previous owner said he'd had it serviced at a local garage whom also changed the rocker cover gaskets... I wasn't too surprised to find only the front plugs must have been changed on last few services, there was hardly any electrode remaining on rear plugs, front rocker gasket had been done but rear hadn't and was leaking. Last time I changed the plugs was when I changed the belt tensioner, took the opportunity as that's a manifold and alternator off job. I should've changed them when I recently changed the gearbox too but didn't, missed opportunity!

Once had a customer ask me specifically to change his inlet manifold gasket, he had diagnosed a problem with the manifold gasket before he came. I don't remember the model or even if it was converted to LPG etc but it was a straight 4 or 5 cylinder engine, gasket was thick squidgy type and someone had recommended me.. I told him I didn't think the gasket would be the problem, real problem would be AFM but he still asked me to change it and then left to catch a bus from just over the road into town while I did the work. He came back 20 mins later saying he'd missed the bus but I'd seen the bus pull away from the stop only a few mins after he left and bus stop is only a 30 second walk away.. Pretty obvious he was checking up on me to see if I was changing the gasket, knowing that I didn't agree with his diagnosis.. He seemed surprised that I already had his manifold removed and was peeling the old gasket out the grooves! :lol: As I expected, changing the gasket didn't make any difference, he came later for AFM changing and that did sort the problem.

Would advise customers of unknown reputation garages to ask for their old service items (plugs / air filters / etc) back on vehicles where such bits are difficult to access, in some cases even when they're not.

Simon
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
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07816237240

Gilbertd
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Re: Spark Plugs - Best Ones To Use

#17 Post by Gilbertd » Thu Dec 03, 2015 6:21 pm

LPGC wrote:
Gilbertd wrote:My mate in France bought a boat with a pair of Volvo 4 cylinder motors in it (marinised version of the old 200 series 2 litre B20 engine)
Prime candidate for an LPG install? :)
Over here maybe, over there, not a hope. When I suggested it when he replaced that boat with one fitted with a 5.3 litre V8, he checked and found that it would be illegal in France. Installs on cars can only be done by certified installers, using approved kit and there are no approved kits for boats.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.

joshnosh
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Re: Spark Plugs - Best Ones To Use

#18 Post by joshnosh » Thu Dec 10, 2015 10:09 am

changing plugs on my car isn't that easy so i go for the iridium ones.

iv had both the NGK iridium and the NGK iridium LPG ones

i cant tell for certain but they look 100% identical even under my little microscope
the packets are also identical

standard gaping for my car is 0.8 but everyone runs 0.6 found my car runs best on 0.4 though

also just to clarifi. the dwell is when the car applies voltage to the coil then when it turns of is when the coil "collapses" and the voltage shoots up to create a spark. so you cant interupt the dwell by having the gap to short

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Re: Spark Plugs - Best Ones To Use

#19 Post by LPGC » Thu Dec 10, 2015 12:30 pm

joshnosh wrote:also just to clarifi. the dwell is when the car applies voltage to the coil then when it turns of is when the coil "collapses" and the voltage shoots up to create a spark. so you cant interupt the dwell by having the gap to short
Agreed because you refer to the usual context of dwell. Without re-reading I don't remember who else referred to dwell on thread but another context of dwell is length of time spark exists, other person may have meant dwell in that context? Some of the more advanced coil packs have extra wire which in some way is used as feedback (to ECU) or properties of the spark.

Simon
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Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
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LairdScooby
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Re: Spark Plugs - Best Ones To Use

#20 Post by LairdScooby » Fri Dec 18, 2015 9:52 pm

LPGC wrote: Would advise customers of unknown reputation garages to ask for their old service items (plugs / air filters / etc) back on vehicles where such bits are difficult to access, in some cases even when they're not.

Simon

Definitely! Over the past year/18 months i've taken over the majority of the maintenance on a friends car that used to have it serviced etc in one of the local garages. The first service i did i discovered a black air filter element, a 3-piece oil filter element (should be one piece), worn out plugs, leaking rocker gasket, dangerously scored brake discs (they had previously advised these and the pads on the MoT and she had said "do it" to them so again, only half the job!), the oil was black and thin and there were several bodges on the exhaust to get an MoT pass!
The MoT this year they shafted her again, saying the headlamp bulbs weren't fitted correctly ( i know they were, they pulled them out and had refitted them wrong as well!) and several other things.
Gilbertd wrote:
LPGC wrote:
Gilbertd wrote:My mate in France bought a boat with a pair of Volvo 4 cylinder motors in it (marinised version of the old 200 series 2 litre B20 engine)
Prime candidate for an LPG install? :)
Over here maybe, over there, not a hope. When I suggested it when he replaced that boat with one fitted with a 5.3 litre V8, he checked and found that it would be illegal in France. Installs on cars can only be done by certified installers, using approved kit and there are no approved kits for boats.
Register the boat and the LPG install here perhaps Richard?
Cheers,
Dave


Somewhere in Suffolk with a Jeep, 2 Rovers and a V6 Volvo

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