To change or not to change spark plugs?

[spavel6]

Here are the old plugs (NGK BCPR6ES-11) I pulled out of a 2001 Saab 9-3. Unknown mileage on these plugs, but they looks pretty beat to me.

I was kind of thinking I would find one clean one due to unidentified coolant loss, but that doesn't look to be the case..

 

[Bgallagher]

Change them

 

[nwjones18]

They're cheap and you already have them out.. Change them

 

[WobblyElvis]

Change them. It looks like the engine is running rich. Short trips?

 

[spavel6]

The car was missing most of the exhaust from the cat-back when I bought it, so I would say the o2 sensors were not functioning properly! I've buttoned it all up, so it's running much smoother now.

 

[69GTX]

They still appear to retain most of their original dimensions which is good.

 

[demarpaint]

If I went through the bother of taking them out, I'd change them. That engine is running rich.

 

[Superflop]

Change them they are too cheap not to. BTW saab 2.3 are rediculously easy to do plugs on maybe 10-15 minute job(for everyone else)

 

[slacktide_bitog]

Yeah, change them! Especially if you already took them out

Use the NGK 6290 (PFR6H10). It is the OEM plus on those cars. Saab switched to platinum when they renamed the car 9-3.

 

[forged]

In my Saabs, I have had no problems regapping these NGK plugs until the electrodes start to become rounded on the otherwise 90 degree edges. Supposedly, the larger the gap, the more current that is required from the ignition. I would regap and use these plugs until replacements could be had at a good price.

My local Saab mechanic says not to use antiseize on the threads because this changes the knock characteristics as detected by the Direct Ignition Cassette (DIC). I use a little anyway. It is well documented to be sure to use dielectric grease on the insulator ends of the DIC to keep the spark where it should be.

 

[Kuato]

Originally Posted By: Bgallagher
Change them

Yup.

 

[toneydoc]

Change out

 

[HerrStig]

Originally Posted By: forged
In my Saabs, I have had no problems regapping these NGK plugs until the electrodes start to become rounded on the otherwise 90 degree edges. Supposedly, the larger the gap, the more current that is required from the ignition. I would regap and use these plugs until replacements could be had at a good price.

My local Saab mechanic says not to use antiseize on the threads because this changes the knock characteristics as detected by the Direct Ignition Cassette (DIC). I use a little anyway. It is well documented to be sure to use dielectric grease on the insulator ends of the DIC to keep the spark where it should be.
A larger than stock gap requires more VOLTAGE to fire, which can stress the ires and coils.

 

[eljefino]

Originally Posted By: HerrStig
A larger than stock gap requires more VOLTAGE to fire, which can stress the ires and coils.


Yup but the engineers account for this and the gap on a new plug is on the tight end of the acceptable range.

They expect it to widen over the given service interval.

 

[Superflop]

Originally Posted By: eljefino
Originally Posted By: HerrStig
A larger than stock gap requires more VOLTAGE to fire, which can stress the ires and coils.


Yup but the engineers account for this and the gap on a new plug is on the tight end of the acceptable range.

They expect it to widen over the given service interval.
the dic (coil) on these are a known weak point and at $350ish a replacement, gap is important this coil pack doesnt just produce spark it is also the effective cam position sensor through ionic return. Correct plugs and gap are important. Replace with clean plugs, do not use anti seize and do use correct torque on cold heads!

 

[spavel6]

Went ahead and installed some NGK BCPR7ES-11 plugs on suggestions above, and this post from saabnet.com. Didn't use anti-seize as you mentioned above, and tightened them ball-park snug. I initially understood that the -11 plugs come properly gapped for this application, but I now wonder if that's not the case.

Interesting discussion from saabnet.com on which plugs, and gap:

Quote:
- Use the inexpensive regular copper BCPR6ES-11 (or BCPR6ES) for primarily city driving where the BCPR7ES-11 (or BCPR7ES) shows a lot of black carbon deposits on the plug tip. The use of the "hotter" heat range 6 spark plug will help reduce the black carbon deposits on the spark plug tip.

- Use the inexpensive regular copper BCPR7ES-11 (or BCPR7ES) for primarily freeway, sustained high speed, spirited driving, towing, or when using an upgraded ECU like Speedparts, BSR, etc.

- Replace the spark plugs every 10,000 to 15,000 miles, depending on your driving style. The BCPR6ES-11 and BCPR7ES-11 are factory gapped by NGK to 0.044". The BCPR6ES and BCPR7ES are factory gapped by NGK to 0.035". The Saab specification has changed over the model years but is generally 1.0mm +/- .1mm (0.040" +/- 0.004"). It is best to gap new spark plugs to the lower end of the tolerance, as the spark gap will wear and increase over the life of the spark plug. Therefore, all the NGK plugs need to be re-gapped to 0.036" before use in the Saab 2.0L and 2.3L turbo engine.

The NGK BCPR6ES-11 and BCPR7ES-11 copper core plugs were Saab original equipment from 1994 thru 1999. From 2000 thru 2002, the NGK PFR6H-10 platinum spark plugs were Saab original equipment, and the NGK PFR7H-10 was offered as an option from the Saab part department for "hard driving". The additional cost of the platinum spark plugs may be justified if you are paying someone else to do the installation and want to run 30,000-miles between spark plug changes. Otherwise, the regular copper plugs perform just as well for less money but need to be replaced more often.