BMW Spark plugs

[325i]

I have a BMW 325i (engine code M54B25) and looking to replace the spark plugs. The current ones were changes 4 years and 24,000 miles ago.

BMW reccomends BOSCH FGR7DQP or NGK BKR6EQUP. I currently have NGK BKR6EQUP which I believe are platinum.

My question is, what do you reccomend as I have an LPG conversion now. Stick with the current platinum ones or upgrade to NGK BKR6EIX which are irridium?

Thanks

[classicswede]

Platiunum and LPG do not mix.

[Gilbertd]

Whereas LPG and Iridium work very well together.

[325i]

Platiunum and LPG do not mix.

What is the reason for this? The ones at the moment seem to be running just fine.

[Gilbertd]

No idea. LPG needs a better spark than petrol but why, as a general rule, Platinum plugs don't work as well as standard copper and Iridium tipped plugs is a mystery. Copper cored plugs are usually well worn after no more than 10,000 miles whereas Iridiums will last at least 4 times as long.

[325i]

Fair enough, just find it strange that a standard copper plug gives a better spark than Platinum plug.

[rossko]

just find it strange that a standard copper plug gives a better spark than Platinum plug.

Don't think anyone has said that, it may be more of a durability thing - if platinum under LPG wears as quickly as copper, why fit - if it wears quicker, even worse.

I have to say I've no particluar experience of 'platinum problems' myself. But then I recoil in horror at Champion brand plugs and prefer NGK, experiences vary.

[Gilbertd]

But then I recoil in horror at Champion brand plugs and prefer NGK, experiences vary.

I'll agree with that from personal experience. Many years ago I used to run big Citroens and went from a DS19 to a DS21 EFi. The 19 had run fine on Champions but the EFi would misfire horribly on acceleration. I mentioned this in my local Citroen dealers and was told to replace the Champions with NGK plugs and it wouldn't do it. They were right and I've not used Champions in anything since.

[E46CoupeM3]

I have a BMW 325i (engine code M54B25) and looking to replace the spark plugs. The current ones were changes 4 years and 24,000 miles ago.

BMW reccomends BOSCH FGR7DQP or NGK BKR6EQUP. I currently have NGK BKR6EQUP which I believe are platinum.

My question is, what do you reccomend as I have an LPG conversion now. Stick with the current platinum ones or upgrade to NGK BKR6EIX which are irridium?

Thanks

NGK do a plug specifically for LPG, use their partfinder, link below


http://www.ngkpartfinder.co.uk/car_comm ... hp?id=4551

[Gilbertd]

NGK do a plug specifically for LPG

They do, but if you look at the technical specs for them they appear to be identical construction and materials to standard Iridium plugs. The only difference appears to be different markings and priced at 3 times the price!

[E46CoupeM3]

NGK do a plug specifically for LPG

They do, but if you look at the technical specs for them they appear to be identical construction and materials to standard Iridium plugs. The only difference appears to be different markings and priced at 3 times the price!

That may be.

You know that plugs also come in heat ranges and often the only difference between two may be how deep the gap into the steel body from the nose ceramic goes.

I recently replaced the BMW branded plugs in my 1995 328
These plugs were in the car when I bought it at 123K miles and have completed 21.5K miles on petrol and 25K miles on LPG. The last dealer stamp was at 75K so potentially these are 94.5K miles old or even older. I replaced with the economically priced and freely available standard NKG plug ,The BMW ones coming out had the same NGK part no stamped in the body.
The gaps were large but there were no missfires when they came out

[woody]

IMHO stick with NGK standard issue, irridium plugs are overpriced and over rated.
Out of all the BMW,s we have converted and repaired , i am yet to see one with a missfire from a plug fault.


Woody

[Gilbertd]

Problem here is that the standard plugs are Platinum and far too many people have had problems running LPG and Platinum plugs to make it worth the gamble. In my experience, the only difference between standard copper cored plugs and Iridiums is that the latter last about 4 times longer.

[E46CoupeM3]

This might be handy

http://www.ngksparkplugs.com/docs/tech/ ... _plugs.pdf

If you have a "standard plug" and it is running too hot or too cold cn probably work out the "same" plug with a different hotter or colder temp range to move away from overheating or fouling

[Gilbertd]

That's the advantage with NGK plugs, their heat ranges seem to be much wider than other manufacturers so overheating or fouling is virtually unheard of. Iridiums are even better which is how they can get away with selling a very small range of their 'special' LPG plugs which only vary in physical dimensions not heat range.

[E46CoupeM3]

I removed the standard plugs from my car at 169.5K miles. The plug gaps were huge and they were totally worn out (but still running fine). These plugs were in the car when I bought it at 123K miles and have completed 21.5K miles on petrol and 25K miles on LPG that I know of. The last dealer stamp was at 75K so potentially they were 94.5K miles old.

Replaced with standard NGK plugs, same part no stamped on them but no dealer branding

With that kind of life span on the standard ones I can't see a point in spending more. I can't see my engine lasting another 180,000 (is's over 180,000 now) in order to need another set

[andy evans autogas]

This is a topic that always raises interest as I've always said Lpg and platinum plugs work excellent together providing the system has been fitted and tuned correctly and I personally have never had a problem with platinum plugs if that's what's recommended for that particular car and the previous post would appear to have a system correctly tuned ..... Say no more ....

[andy evans autogas]

Here's a link to one I did about 7yrs ago that's just had the platinums changed as they only lasted 120,000 miles ......
http://youtu.be/fFUWm06oMJU
Oh and obviously replaced with platinum NGK's as recommended