Which Spark Plugs

[Mr Hardware]

Hi All

I have a 6/2000 AUII with Factory Dual Fuel. I don't know which type of spark plugs to buy. The NGK website tells me that BPR6EY's are the go, which are 0.8mm plugs whereas the petrol equivalent is listed as the BPR5EY-11s which are 1.1mm gap.

What is the difference, and which one is right?

[Chamelion]

I used NGK ZGR6B11 in my AU3 Forte on LPG. This plug was reccomended by Torquegas. I'm rather happy with them. Much better than the Ford supplied Iridium plugs that were in last time.

These ZGR6B11 are only $2.75ea at my local CarBitz.

Matt.

[bodes-sh]

normally ngk petrol plugs, you can gap them down if you want, i have standard ones in mine at 1.1mm gap and haven't had any issues with backfires, etc

[InfernoSR]

I was told that the Dual Fuel runs better with the shorted gapping, also found in the XR6... which is what i ended up using anyway... :P

[Jastel]

I have used both the BPR6EY and the ZGR6B11 in my taxis, wasn't looking for high performance or anything just no backfiring

Found no real difference between them, if I recall they changed the recomended plug halfway through the AU range but both worked

The "5" and "6" in the number is the heat range with the 6 being a cooler plug recommended for gas

I always used .8mm gap as well, whatever plug type

[GK]

My gas guy always uses the normal recommended petrol plug gapped to 0.8-9.I tried gas plugs myself but they made the car run like a dog. I've used the stock plugs (non-iridium) since.GK

[bodes-sh]

apparently the petrol plugs perform better than the recommended lpg plugs, so i'd just get them and gap them down to 0.8 if it concerns you

[Mr Hardware]

okay, sounds interesting

seems i currently have Denso .8s that are recommended by denso for AU1 LPG motors... but not AUII. I don't see that there's any difference between one AU silvertop and another, is there?

[EvilChief]

little sticker on underside of bonnet recommends plug gap, which IIRC is 1.1 for petrol.

gapping down from factory specs is only done, when ignition issues arise under high boost application.

most NA cars run 1.1 to 1.5 gap, most turboed cars run 0.8 to 0.9 gap (as a rule of thumb, but check factory specs)

simply gapping down a plug does not neccesarily mean better power or economy, in many cases it does quite the opposite. a smaller gap produces a smaller spark, which in turn then cause not fully burnt air fuel mixture, hence shitty economy and power.

[PoweredByCNG]

Dedicated LPG engines should be running spark plugs with a smaller electrode gap (< 1.0mm) and one heat range colder than petrol plugs.

Regards,
Dave

[Mechan1k]

I tossed my Iridiums (too expensive) ... and went with standard NGK's gapped down to 0.8mm
Much cheaper ... works a treat ... so far I have managed just over 20,000km without a hiccup yet ... so looking good for my dedicated LPG ute.

[blueoval]

I havent come across having to replace spark plugs yet, but when I do I'll make sure I get correctly gapped ones to suit dual fuel.

Is there a plus that suit dual fuel applications rather than just one or the other?