spark plug question for a six Options

[rfuerst911sc]

I just ordered some Clewett spark plug wires for the six and I'm going to change the plugs at the same time. Ignition rotor and cap are only 6 months old. Engine is a stock internal 3.0 with Weber carbs and Mallory multi spark ignition. All my records are still in moving boxes and I haven't pulled the old ones yet so what are the recommended plugs/heat ranges for street driving ? I generally like NGK standard copper plugs but have run copper Bosch in the past. Thanks and happy new year (IMG:style_emoticons/default/beerchug.gif) .

[J P Stein]

BP6es should be close. It takes a bit of fooling around to get spot on.....but it's cheep. BP5 is hotter, 7 is colder.

[JoeSharp]

(IMG:style_emoticons/default/agree.gif) Tottaly...

[carr914]

(IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/beerchug.gif)

[rfuerst911sc]

Any advantage to use the BPR6ES vs. B96ES ? I assume the " R " version has a resistor built in ? Is that for noise suppression or actual resistance for voltage ?

[J P Stein]

I don't know. I collected a good size box of the normal 6s & 7s over the years having never felt the necessity to use anything else.....no radio here. (IMG:style_emoticons/default/biggrin.gif)

[ME733]

...I wish their was an absolutely clear deffination for the ..R...plug designation., but generally the ..R... designation means a Retracted TIP....this would give you some extra clearance if using high compression pistons., generally the ...R..designation is on plugs with a colder than "stock" heat range., In my opinion all engines run better with the Hottest spark plug heat range the engine can tolerate before "signs of detonation " or "overheating" of the plug occur.

[Cap'n Krusty]

Reality check!

Early 3.0 engines used one plug, late engines used another. Carbs, especially with "modern" fuels, need a hotter plug than is specified for CIS engines. "R" is for resistor, and most new plugs have that feature. Bosch uses the ":C" designation for non-extended tip, "D" for extended. NGK uses "P" for extended tip, no letter at all for standard tip. A "cold" plug transfers heat away from the tip faster than a "hot" plug. 911s have traditionally run non extended tip plugs. PMO advises running the hottest plug you can get, more or less, and they know quite a bit about 911s with carbs. The book calls for them. However, at some point they changed, probably with the 3.2.

The Cap'n

[ME733]

Reality check!

Early 3.0 engines used one plug, late engines used another. Carbs, especially with "modern" fuels, need a hotter plug than is specified for CIS engines. "R" is for resistor, and most new plugs have that feature. Bosch uses the ":C" designation for non-extended tip, "D" for extended. NGK uses "P" for extended tip, no letter at all for standard tip. A "cold" plug transfers heat away from the tip faster than a "hot" plug. 911s have traditionally run non extended tip plugs. PMO advises running the hottest plug you can get, more or less, and they know quite a bit about 911s with carbs. The book calls for them. However, at some point they changed, probably with the 3.2.

The Cap'n

And while the "R" designation is for resistor plugs (generally)...the "R" in Champion plugs is for a retracted tip..(very retracted) tip...in their race plug series. For resistor plugs, do this, use a multi meter across the ground and electrode. on occasion you can find a plug with no reading or one that is below all the rest. Use the ones that are equal in resistance. This ensures that the plug heat range is equal, and eleminates "phoney" and" mystifing " carburator adjusting and unequal cylinder burn.

[Cap'n Krusty]

Well, that's Champion, a plug virtually no German manufacturer uses, 1500-2000 CC Carrera engines excepted .................... I certainly wouldn't put 'em in my customers' cars.

The Cap'n

[ME733]

Well, that's Champion, a plug virtually no German manufacturer uses, 1500-2000 CC Carrera engines excepted .................... I certainly wouldn't put 'em in my customers' cars.

The Cap'n

German cars don't use them because they are NOT made in germany. Champion plugs have a vast array of plug types, sizes,and heat ranges, Probably more than all other manufactures combined.

[Cap'n Krusty]

Well, I disagree with you, and I've been working on Porsches since 1963. Champion plugs had, at that time, and for a long time thereafter, cut threads, while Bosch, Lodge, NGK, Beru, and possibly others, had rolled threads. I don't know if that's still the case. Cut threads were hell on aluminum heads, and we saw thread damage on countless engines, both VW and Porsche, that were running, or had run, Champion plugs.

As for you "Not Made Here" theory, VW, BMW, and others come with NGK plugs as original equipment, and Porsche has used both Motorola (US) and Valeo (French) alternators and regulators for years.

The Cap'n

[JoeSharp]

I use NGK's on every thing I can. I like them because they didn't foul like the Chumpion's did. Yeah I bought the High Dollar stuff and always went back to the NGK's. Now days I buy cheap NGK's in 2 or 3 heat ranges and tune the car looking for the correct range. When I find it I put in a cheap set and wait for them to fail. When or if they do I buy the expensive NGK's and put them in. I have not had a problem for many years.
Captin Krusty has had many many years making his living working as a Pro. I have never known him to put out anything but the cold hard abrupt truth...
He has earned his handle as well as I have earned my reputation. Any that oppose him will only be banging their head against a wall (IMG:style_emoticons/default/headbang.gif)

[rfuerst911sc]

Reality check!

Early 3.0 engines used one plug, late engines used another. Carbs, especially with "modern" fuels, need a hotter plug than is specified for CIS engines. "R" is for resistor, and most new plugs have that feature. Bosch uses the ":C" designation for non-extended tip, "D" for extended. NGK uses "P" for extended tip, no letter at all for standard tip. A "cold" plug transfers heat away from the tip faster than a "hot" plug. 911s have traditionally run non extended tip plugs. PMO advises running the hottest plug you can get, more or less, and they know quite a bit about 911s with carbs. The book calls for them. However, at some point they changed, probably with the 3.2.

The Cap'n

Cap'n what plug would you recommend ? I did know that early ( 78-79 ) used a different plug then late ( 80-83 ) but I don't know if that is just for the CIS cars ? To your point I'm running carbs on both engines.

[ME733]

Well, I disagree with you, and I've been working on Porsches since 1963. Champion plugs had, at that time, and for a long time thereafter, cut threads, while Bosch, Lodge, NGK, Beru, and possibly others, had rolled threads. I don't know if that's still the case. Cut threads were hell on aluminum heads, and we saw thread damage on countless engines, both VW and Porsche, that were running, or had run, Champion plugs.

As for you "Not Made Here" theory, VW, BMW, and others come with NGK plugs as original equipment, and Porsche has used both Motorola (US) and Valeo (French) alternators and regulators for years.

The Cap'n

................Well capt. lets see, The carrera 4 cam engine you spoke of in an earlier post...One of the highest output per cubic displacement ,carburated naturally asperated, engines of all time...USED CHAMPION plugs.....the since 1963 porsche engines as you you state, ALL have helicoil inserts,(all 356 engines have heli-coil inserts)(factory installed) therefore the spark plug has NO direct contact with the aluminum cylinder head. The only way anyone can have a problem is IF you remove the spark plug in a red hot engine...which knowledgable engine guys would never do...Additionally knowledgable engine guys use a small dab of Anti-sieze on the plug threads, wether or not the spark plug threads are heil-coiled or not...The type four engine heads do not have heli-coil spark plug inserts. A dab of anti-sieze on the plug threads is essential to preserve head thread integrity.