WARNING: '72-'73 911E Owners ... Error at NGK Website -- BP6ES/BP-6EVX Too Hot!

[Early_S_Man]

The NGK Part Finder application incorrectly lists the following three plugs for 1972 and 1973 911E engines: BP6ES, BP6EY, & BPR6EVX, which are one step HOTTER than the recommended spark plugs for all 911T engenes! As some may not know ... the SAME heat range spark plugs are recommended by the factory for all 911E and 911S engines prior to 1974!

Because of the taunting of a certain very young newbie about my recommendation of NGK BP-8ES plugs for a '73 911S ... and his insistance that BPR6EVX were perfectly safe in a '72/'73 911E, and hence, also safe in his 911S ... I decided tom do a bit of checking at the NGK website ...

Quite a few glaring errors and discrpancies are evident in their 'NGK Part Finder' ...

For 1965 models, only 356 and 912 are listed ...

For 1966 and 1967, only 912 is listed ... and, no 911S or 911T models are listed for 1968!

For '68 911L engines, the NGK part finder indicates B8ES & B8EVX ...

For all '69 thru '73 911S engines, the NGK part finder indicates ONLY the Platinum BP8EVX, however the fuel system is listed as 2 x 3 Bbl. carbs!.

For '69 thru '71 911T engines BP7ES and BP7EVX are listed. For 1972 911T engines only the Platinum BP7EVX plug is listed, but only the 'TV' carbureted engine is shown. For 1973 the MFI 911T engine lists the BP7EVX plug, and CIS engines list the B7ES and B7EVX plug.

For 1969 thru 1971 911E engines, the recommendations are the same as 911S engines, BP8ES and BP8EVX.

As you can see the '8' heat range was consistently rercommended over the years for 911S engines, and the '7' heat range plugs wer recommended for 911T engines.

While the '6' heat range spark plugs might be safe in winter in Canada or Northern USA snow belt states for use in the 911E engines, I feel there is significant risk of preignition or detonation in hotter climates such as Southern USA states in the summer!

The NGK tip styles and other letters can be decoded by looking at this chart:

http://www.ngksparkplugs.com/techinfo/spark_plugs/partnumberkey.pdf

[andrew15]

Great info, and definately appreciated!

Just a quick question though, while tuning webers it is sometimes recommeded to use a hotter plug (to prevent fouling?). Would the 6 range be adviseable for this purpose or do you have a different recommendation?


Regards,
Andrew M

[A Quiet Boom]

FWIW, the company that supplied me with larger venturis for my Zenith carbs on a 3.0 recommended a BP5ES for tuning purposes only, then switch to BP8ES or BP9ES. I have used this very same trick when dialing in dual Holley carbs on drag engines and nearly destroyed an engine by forgeting to swap out the plugs for cooler ones. Fortunately I shut it down mid-pass and no damage occurred.

Big UP to Warren on this one, always helps to have the correct information.

[Early_S_Man]

Here are some liks to useful info about NGK Spark plugs ...

This is an Excel spreadsheet with cross references toother mfr 's numbers ... be careful, though, because some of the NGK numbers show crosses to multiple heat ranges from the other company!

http://www.ngksparkplugs.com/techinfo/spark_plugs/partnumberkey.pdf

This is another Excel spreadsheet with data on various racing plugs:

http://home.att.net/~ngkaz/wsb/Racing_Plugs.xls

[DavidPorter]

So OK, what is the proper NGK plug for a '72 T? Does it matter whether MFI or Webers?

Thanks.

[Early_S_Man]

Well, since the factory says to use the same plug as the 911S engine, NGK's 'official' recommendation would be the BP8EVX. The B8EVX, B8ES, and BP8ES also work.

What I normally recommend for street driving is BP8ES for the summer, and BP7ES for winter. YMMV

[Shuie]

Intentional bump for a two year old post.

I went to a BPR6ES two months ago after doing CMA and pulling my Bosch W3DPO platinum plugs. The Bosch plugs were black and sooty as expected. I did some searching for replacement plug options and found some old threads saying to go to a hotter plug like the BPR6ES. My car was real happy with them initially.

We have had a pretty cool summer here until the last few weeks. Heat index has been getting above 100 degrees regularly. My car still runs real well at startup, but after it warms up, it feels like its starved for power (like it did when it was running lean before CMA) and its pinging at idle. I never thought I would have detonation issues with a low compression T engine. Confused, I started searching here for reference to the BPR6ES plug. I'm going to a cooler plug after finding this thread.

Whats the difference between a BPR8ES and a BP8ES? What function does the Resistor have?

Thanks again Warren! Everytime I search old threads for something specific I find info you have posted that helps out.

[Wil Ferch]

Warren...or others....how does this new-found information find its way back to the NGK website ?? Corrective Feedback like this is necessary for any database....

---Wil

[}{arlequin]

now I'm getting nervous b/c I never checked what plugs Pelican sent me w/ my "tune up" kit and I remember some people saying they received wrong plugs. They are not installed yet, are the numbers on the boxes or on the plugs themselves?

Then again, my current set of plugs in the car is straight from an independent (very good quality and reliable) shop. I remember the plugs were in little "porsche" boxes (I think) and they definitely did not look copper. Silver metal in appearance, so after a search I felt that I had the wrong ones in there all along.

Other than an occasional part throttle misfire, the car seems to run fine, starts hot and cold w/ no problems etc etc. Then again, those misfires could be the result of the plugs too, right?

[pwd72s]

Once again, many thanks Warren...I just posted a link to the Early S registry tech board. Not everybody over there drives "S" models.

[campbellcj]

FWIW my engine (a 2.2S/T) has been doing well on BP7ES plugs. I have a set of BP8ES on hand and am now wondering if I should swap for the Sept-Oct track events. Hmmm...

I agree that the 5-6 NGK heat ranges seem awfully hot for "normal" engines and American driving conditions.

[DonDavis]

I was poking around for spark plug info.

Sherman, what plug did you end up using for your '72 2.4T MFI. The description below is how my car runs but no pinging. I'm going to change out the wires, cap and rotor as well.

Originally posted by Shuie
My car still runs real well at startup, but after it warms up, it feels like its starved for power (like it did when it was running lean before CMA) and its pinging at idle. I never thought I would have detonation issues with a low compression T engine. Confused, I started searching here for reference to the BPR6ES plug. I'm going to a cooler plug after finding this thread.

And Warren, I know the temps in San Angelo very well. Lived in Big Spring. For AZ summer driving would you still go with BP8ES?

One last thing. Any plug wire solutions aside from factory? It stock through and through.

[}{arlequin]

pretty useful website:
http://www.sparkplugs.com/default.asp

[Jim Richards]

So, what's the right plug (NGK or Bosch) to use on a 2.7RS engine?

[Shuie]

Originally posted by DonDavis
Sherman, what plug did you end up using for your '72 2.4T MFI. The description below is how my car runs but no pinging. I'm going to change out the wires, cap and rotor as well.

BPR8ES. Ran great with zero issues after switching to these plugs. I played with MFI a good bit to get it running well.

[Early_S_Man]

Guys,

The sparkplugs,com website makes the same 'too hot' recomendation as NGK for the '72 - '73 911E engine ... NGK B6 series, and Champion RN9YC!

The 911E recommendations should be the same as for 911S, which does seem to be OK ... NGK B8 & Champion N3YC!

[Jim Richards]

Warren, what's good for the 2.7RS engine? Either in a Bosch or NGK? Platinum or not? Thanks!

[jclotz]

Hmm. Based on the recommendation from the PMO website, I have been running PB5ES in my 72T with Webers and MSD. Plug gap is 0.040. Originally set the mixture with Colortune then have been fine tuning by visual checking of plug condition. Engine has been running great over the 500 miles or so since I changed to these plugs. What are the catastrophic things I should be worrying about (since I am always looking to add things to that list). Assume any damage would have already occurred by now.

[RoninLB]

Originally posted by }{arlequin
pretty useful website:
http://www.sparkplugs.com/default.asp

nice. I was looking for a cross reference.

thx

[RoninLB]

I like to run the coldest plug possible. The BP8ES/BPR8ES is pretty cold. The BP9ES/BPR9ES is super cold. A rich mix will equal cool EGT's which sometimes can be fouling alleviated by running a hotter plug. The game should be to tune your fuel&air mix to a proper egt and match the plug to that. There is a noticable difference in plug tip temp's between numbers so I may tune like A Quiet Boom and then run the coldest plug possible for conditions.

Starting at a cold plug and working hotter is much safer than starting hot and working cold. To hot a plug for the mix leads to preignition and very soon should lead to detonation. Detonation wrecks engines as egt's skyrocket+

Faking a poor fuel mix for your driving conditions with a hotter or colder plug is not efficent for hp production. A single egt probe and ga install is not a bad idea.