Spark plug recommendation pls

[Peter Coomaraswamy]

In reading through the recent posts I feel that this is insignificant but has anyone experienced a truly defective spark plug? I believe I have in that it works intermittently; My car had a miss in it so I started at the lowest common denominator, the Pertronix, but that seemed all set up correctly so I went to the timing (this is after I changed new carb base plates and ruled out vacuum leaks). When I put the inductive clip on #1 wire there was no strobe, I checked all the other wires and the strobe was flashing like an old disco. I checked the wire-through the cap- changed out the wire-and the cap (with the old one) and still no spark/strobe. I pulled the plug and attached it to the wire and got a spark from the tip of the plug, but when I put it back in I could get no strobe. In minor confused desperation I switched with the plug next to it and the #1 immediately started flashing like mad but the one I switched it with was dead. The plugs were brand new and were Bosch (Chinese?) Platinum Plus. Is there a better plug for these cars? Or did I miss something in my diagnosis?

Any help/comments appreciated,
Thanks

 

[lloyd]

I have had my fair share of plugs that looked fine but didn't perform as expected. Most of the issues have involved misfiring due to exterior arcing. You mention platinum plugs that have a better reputation with later high energy ignition systems. I have serviced family non-coupe engines with platinum plugs and on two occasions discovered the suspect plugs had lost the tiny center electrode. Unknown why the electrodes were missing or where they went.

Mass produced spark plugs may have a good track record for reliability, but they are far from perfect. Considering that a large part of each plug is porcelain insulation, they don't take kindly to being dropped or struck by a wrench. Improper installation or heavy detonation/preignition might also lead to shortened plug life. Thus, they can be defective from the factory and then there is the possibility that they can be rendered defective due to poor handling on the retail end or abnormal use. I tend to think you merely got a bad plug from the git go.

I think the conventional wisdom of using either copper or silver core plugs still holds true. NGK BP5ES or BP6ES or Bosch Silber equivalent seems to be favored by most of the E9, E3 and even '02 crowd - despite the introduction of platinum and iridium.

http://mechanics.stackexchange.com/...melting-or-falling-of-my-bosch-platinum-plugs

http://www.globaldenso.com/en/products/aftermarket/plug/basic_knowledge/troubleshooting/index.html

 

[Bert Poliakoff]

On the E24 boards, the word is not to use platinums as they do not run right in the M30s. Either Bosch silbers or NGK plugs

 

[sfdon]

If you are using Bosch plugs and they say brazil, or Russia or India on them- just throw them away.

 

[Peter Coomaraswamy]

OK, I'm off to the auto parts store for some NGK's. Unless I can find the German Bosch, which I know is impossible. It's horrible to me that a country such as India (my ancestral homeland) and one of the most industrious nations on the globe can produce such garbage. I have a shovel that lasted less than 1/2 hr before the welds broke and some textiles that are hundreds of years old that are still sturdy and colorful... go figure- a topic for another day.

Hopefully I can report good news tomorrow- Thank you all!

 

[Bert Poliakoff]

Steve Haygood who is one of the most knowledgable M30 guys around, put me on to the NGK's. Maybe others will chime in here, but Steve told me, IIRC don't be affraid to gap a loose .o33

 

[David]

On the NGKs, are you running the BP5ES or 6ES ? I think .033 is higher than stock, correct ?

 

[Stevehose]

German Bosch W7DC (eBay) or NGK BP6ES gapped at .028, .030 max with Pertronix. Run away from the other stuff.

 

[m_thompson]

My 323i would not start during the winter with Bosch Platinum Plus plugs installed. It started fine with normal Bosch plugs. I have heard of lots of other problems with the Platinum Plus plugs.

 

[Mike Goble]

I use Autolite 64's in my Bav, never a problem. I gap them at 0.050" and fire them with an MSD-6T box.

 

[bavbob]

Bert is correct. I cannot find a site that says to use platinum in the e24, only silber. I use silber or copper in my Bavaria as with my e24.

 

[Sparky]

Platinum plugs

My bone stock '78 635csi would foul new Bosch Platinum plugs in just a few minutes. It ran great with regular electrode plugs.

 

[lip277]

Yes... NGK's all day long. BP5ES or BP6ES. Used them for 28 years in the M10 engine in my 2002. The M30 I have is also treated to that plug.

Used NGK's in my 420SEL, Yukon, E38's (two), Explorer, JD mower, Honda mower, Honda pressure washer... you get the idea...

 

[Bwana]

What is the secret code number/suffix for a BPR6ES with the removable tip like we need? I saw it once here but can't find it now. No way to tell from what I've seen on line and Autozone/ORilleys/NAPA don't list a difference, you have to take one out of the box

 

[deQuincey]

ngk iridium BPR6EIX

fine for me

 

[Bwana]

^^I wonder if it makes any difference with a D-Jet system?

 

[lip277]

No - for me it would not. I have used those plugs in FI and Carb'd engines and they run great for both.

 

[ohio2800cs]

What is the secret code number/suffix for a BPR6ES with the removable tip like we need? I saw it once here but can't find it now. No way to tell from what I've seen on line and Autozone/ORilleys/NAPA don't list a difference, you have to take one out of the box

Stock number on the NGK BPR6ES box is 7131

 

[Vern]

Bosch has discontinued the straight copper core line. I used W8DC for naturally aspirated and W7DC for turbo applications. Go with the NGK plugs. There is ZERO need for a resistor plug in this day and age. Modern gasoline is so far removed from the garbage of yesteryear. A straight copper core plug or silver will lower cylinder combustion temps by 350°F and reduce NOx emissions.

 

[Vern]

ngk iridium BPR6EIX

fine for me

Negatory on the 66th element of the Periodic Table, Kind Sir...Please, let's remember...

This is what I refer to as the Old Dumb Bosch Technology Era. A time when fuel was pissed into the air stream based on a floating voltage measurement. I loved it with my E23 turbo cars, because I pantsed E55 AMG cars in 2002. Anything Motronic 1.3 and earlier was based on shitty gasoline from 1976 to 1989.

As a corollary, spark plug technology gravitated toward higher burn temperatures and no one at any of the Bosch fueled car companies issued updated spark plug requirements until 2016. Bosch ditched their copper straight core line and retooled the W7DC and W8DC plug lines to a resistor line.

ANY modern spark plug, such as a platinum or iridium line in a classic BMW is a waste of money and performance. Period.