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My 164S currently has NGK BKR6EIX spark plugs. I only drive this car (or any of my cars) like a little old lady. I never exceed 4K RPM or use a lot of throttle. Looking at the plugs now (also looked at the plugs 7K miles ago), it looks like I could maybe benefit from a slightly hotter plug. Digging around on the internet, it looks like the BKR5EIX-11 would be the next hotter NGK plug.

Anybody use a hotter plug than the BKR6EIX? Anybody ever use the BKR5EIX-11? Any input from people with experience would be appreciated.

Over the decades, I have tried lots of different plugs on my NORD engine in the Alfetta, and have lots of opinions on that, but I have no experience with the V6.
 

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For one thing, I would up your rev limit to 4500-5000 a couple of times as you do each drive. That would help. So would a little more throttle. The car has actually been designed for more of each, and would actually keep everything a little cleaner. You are not doing any harm to the V6 by doing that. It's a better engine than how you are using it.

Second, I would change to the standard range NGK iridium plugs, as they run cleaner, and last a heck of a lot longer.

Third, I suggest using a little fuel injector cleaner such as Techron now and then in order to keep the injectors, combustion chamber, and plugs cleaner.

I do all of the above, and the 91S engine in my 164 still runs just fine at 193k miles now, never been apart.

Enjoy the car/engine as it is designed. You'll like it more.
 

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Iridium tipped spark plugs are said to last indefinitely. Ford specs these with a change required only every 100,000 miles I suspect because that's the target mileage for your government's welded hood emissions policy (my name for that, not official).

I have found that iridium tipped plugs also behave as if they are one heat range colder than specified in terms of combustion performance. By that I mean these plugs do not need to be as hot as a standard copper cored plug to fire cleanly even if "too cold". You of course recognize that a "cold" plug is nothing of the sort. All plugs run very hot indeed.

Iridium tips are essentially immune to wear so can and should be installed with the maximum specified gap. That wide gap obviates the need for multiple ground plugs often used by Alfa. Multiple ground designs were engineered to extend plug life and improve probability of a clean fire. As each ground eroded the spark would generate from the closest of the four gaps (or three in some cases, and technically the spark would generate from the lowest resistance gap, for whatever reason the resistance was least). Iridium plugs simply do not change gap for the service life of the plug. They are essentially permanent plugs in our engines, unless they get fouled or fail mechanically (compression leaks still sometimes cause plug failure but very rarely these days).

In the 70's Alfa actually supplied a set of colder plugs with every sportscar. By then it was merely an affectation but at that time Alfa actually recommended you change out the hotter plugs for the colder set for extended periods of high speed or spirited driving !!!! Just like your racing car don't you know.

Unless your engine is failing to fire cleanly then you have the correct plug. Recommendation is to run the coldest plug suitable for your engine. You definitely should not run a hotter plug than you need to. The detonation resulting from too hot a plug can destroy an engine in minutes and the driver will not be aware it is happening. Preignition from a too hot plug is not prevented by any knock sensor because it is not caused by ignition timing nor fuelling.

For Canada NGK recommends the 6 heat range which is possibly not necessary in warmer climates. Our engines run cooler and richer for longer while warming up in the dead of winter (-30C this morning, colder tomorrow) and can occasionally benefit from running a hotter than normal plug. But I have found in my SAAB turbos, which need a wide heat range plug because of the widely variable combustion chamber pressures and temperatures as well as the detonation risks due to the very hot and high pressure conditions under full load, that the NGK 6 in platinum or iridium actually runs as cleanly as a 7 when the engine is under full load and fully warmed up, and also runs better when the engine is cold or under light loads than the 7. Your engine is fitted with the correct NGK heat range 6 for your described driving.



NGK in fact also recommends a colder range 7 iridium plug for this engine. Standard copper core plug was likely a 7 heat range (NGK heat ranges give higher numbers to colder plugs). You have already fit the hotter plug NGK recommends. I'm not sure I follow Del's suggestion about "standard" iridium plugs. NGK only recommends platinum or iridium X, either of which would work great in our old engines designed to run copper core plugs. I'm not aware of NGK recommending a different range of iridium plug to their excellent IX series.

I concur with the Italian tune up* works very well with these engines although can inflict damage on your driver's license if conducted as per the full Italian regime, redline in each gear possible. I also concur that using fuel injection cleaner once in a while is a good idea for these old engines. If you like the Techron brand ( and I do although cannot buy it here any longer) then buying your premium fuel at a Chevron station gets you all the techron you need. If you occasionally fill up with 94 you get even more techron per gallon....

* related to Italian cruise control, which is simply placing your right foot onto the accelerator and pressing it to the floor. Keep it there. Car control is effected by use of the steering wheel only. And remember, the first rule of Italian driving: what's behind you is not important...Fangio's professional advice for better lap times? More accelerator, less brakes. And so on.
 

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I've generally never used the 'Italian tuneup' in normal driving. Maybe close to full throttle now and then in mid range though, not to red line, maybe 5500 rpm and only up to the local speed limit (more or less), mostly for the Alfa sound. The only times I've used something akin to the 'tuneup' was when I had to take the car to the smog check station. Carlo always recomended doing this on an uphill run a couple of times to blow the exhaust particles out of the cat. I guess it always worked, as I never had an Alfa fail a WA State smog check. Boy, did the junk blow out the rear at first. Pitied the drivers behind me as I did it, lol.

I don't understand how Tom can withstand the visceral urge to drive his S a little more enthusiastically, heh, heh. It's there for the enjoyment and sound. I've enjoyed it since 1994, 193k miles ago.
 

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Don't change heat range, use the same plugs, drive it a little hard from time to time and they will be just fine. Use techron. Take it on long drives as well. No need to change anything or do anything special here.
 

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Don't change heat range, use the same plugs, drive it a little hard from time to time and they will be just fine. Use techron. Take it on long drives as well. No need to change anything or do anything special here.
Agree 100%
 
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