NGK Iridium vs. Platinum Spark Plugs for 328

These kind of questions are always fun....half the people say stay with stock and the other half say try the New technology. You can go to www.ngk.com and they will list all the crosses. There was a thread a couple of weeks ago that covered this same topic. I went with DR7EA (traditional spark plug) for my 348....just a little hotter because most of my driving is in town , not WOT or track. The shop in Calif that did my TR major service also used NGK 7's. From previous articles in Forza, they mention that NGK is the only brand to use today. Standard plugs are so cheap now days that we can change them often. Be careful asking others/dealerships for advice, some of our cars are old enough or rare that the guys haven't worked on many. Two dealers told me the engine had to come out to fix the distributor cap filling with oil and the old guy at the third said a pickel fork and twenty minutes. One last thing, you wouldn't use 20 year old tire technology so try some new spark plug designs. Good luck!

Jeff Pintler
89 348tb, 86 TR

 

Based on my experience with these plugs I'm firmly in the new technology half. Since I installed NGK Iridiums last year my car immediately started better/easier and has since run literally without a hiccup. Prior to these it had standard Champs and did run with hiccups.

 

8 years ago my Dino would not pass smog. Was again hard to start on cold wet mornings. Had religiously used Champ plugs. Had to change every 3000 miles or hard start; but Hey, Recommended by Ferrari in 1972.

Put in NGK BP7EV, passed smog, started every time, for more than 40,000 miles. Changed recently just for the Hell of it and found they were obsolete. Bought NGK Iridium and they worked just like Platinum. Might last longer but I may not live to see the end. BPR7EIX is the current number. Resistor does not seem to cause any problems. About $8 ea. and they probably will have to order. Generally available next day.

NGK heat ranges go opposite Champs in different steps so there is no useful correlation. Go modern.

John

 

Anyone know what the recommended gap is for NGK D8EVX for an '89 328?
Are they preset from the factory?
Cheers
Simon

 

yeah. I was running synthetic 5w40 in a 328 and had some oil weepage. I replaced the engine and switched to dino oil, and the leak stopped. Clearly dino oil is better

either of the plugs has proven to run the car well. Decide how often you want to change plugs, how much you want to spend, and don't worry about it.

unless you have an aftermarket ignition, the factory gap on the plugs is fine. I usually check them, and they've always been .26 on the dr8eix's

 

I've seen some problems using Shell fuels with spark plugs with Resistors in them...

eg.. the 308QV used BP7or8EV originally, but the modern superceded option is now BP"R"7or8EIX.....

I have a spark plug tester and you can easily see the difference when using a resited plug over a non resited one. If you do a lot of city driving, and/or fuel quality is questionable... try to run non resisted plugs.

BP7or8EY, Which have a V grooved centre electrode, is my choice after speaking to NGK Australia.
Only cost AUD$3 too.

 

Phil -

I'm certainly not a spark plug junkie... why does the resistor+mediocore fuel make that much of a difference? Does the resistor magnify the fuel issue?

 

It quite simply dulls the spark... meaning a less efficient burn which reduces the self cleaning ability.

 

If you replace your plugs at under 20K-miles of use... then I see no reason to use anything other than Copper.

 

I know the rule of thumb..seat it and then 1/4 turn..but hey i have this neat torque wrench to use and might as well be percision about it...

 

ok went here http://www.ngksparkplugs.com/techinfo/spark_plugs/installation.asp?nav=31300&country=US

and I think the rule of thumb may not be accurate enough.... there is a lot to this sparkplug torque stuff...anyway the ngk iridiums , according to the table would be torqued to 14-21 , did i read that at all right?

 

The 'rule of thumb' is fine for plugs...just don't forget to antiseize them.

 

THe more you know, the more you learn what you don't know....

I was a naive innocent simple "rule of thumb" (1/4 turn after seated) guy my whole life...even with the alloy head of the xke.. but this thread has dropped me into sparkplug university.

so.....I learned that if you use anti-seize, you must reduce torque spec on the sparkplugs by 40% (any idea about this?)

also learned NEVER use anti sieze on "coated" plugs...are the iridium plugs "coated"?

"Indexing" - lining up the electrode with the exhaust valves for more power..anyone do this.? waste of time in a QV? Only for racers who want max power?

Finally, is rule of thumb 1/4 turn or 1/8th turn.... I am learning how impt. spark plugs are to the engine performance and have become , sadly, obsessed over this.

 

Check the owners manual if you have one -- it's quite possible that it has very specific instructions. At least this is the case with the 328/Mondial 3.2 -- from the 3.2 OM:

Prior to fitting the plugs make sure that their threads are lightly coated with graphite grease. If the spark plug sealing washer is new, first tighten to a maximum torque of 15 ft lbs, then slacken and retighten to 12 ft lbs.

 

Montcalir comes through! THanks Peter, that helps a lot , will check the QV manual...I was getting obsessed over this, (p.s. real nice mondi) I really had no idea how impt. a sparkplug is to the engine performance and what the hot/cold plugs really mean and how critical the correct plug torque is to cooling the engine

 

Glad to help. I approached it the same way as you -- spent a lot of time researching what plug to use and making sure I had the correct anti-sieze and torque settings. Part of the fun of working on these cars is that you obsess over items that would be relatively trivial decisions on other cars.