I ordered the tune-up kit from MSA for my car. I expected (assumed?) to receive BPR6ES spark plugs with the kit, but got BP6ES plugs. Now I understand that the BP6ES are what are called for in the FSM, but I also like simple pleasures like static-free radio reception and clear cell phone communication.

I know all of the benefits of using resistor plugs. Are there disadvantages? Why in this modern age of electronics would I WANT to use a non-resistor plug in my car.

From NGK

Q: When should I use a resistor spark plug?

A: NGK "R" or resistor spark plugs use a 5k ohm ceramic resistor in the spark plug to suppress ignition noise generated during sparking.

NGK strongly recommends using resistor spark plugs in any vehicle that uses on-board computer systems to monitor or control engine performance. This is because resistor spark plugs reduce electromagnetic interference with on-board electronics.

They are also recommended on any vehicle that has other on-board electronic systems such as engine-management computers, two-way radios, GPS systems, depth finders or whenever recommended by the manufacturer.

In fact, using a non-resistor plug in certain applications can actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels and abnormal combustion.

So the answer is.......who knows. The only electronics you have is a stereo (assumed to be an aftermarket unit). Most of these have decent RF supression built these days. It's unlikely given the fact that you're using a coil and distributor (no ecm) that those plugs would have any detrimental effect on your L6. Only after installing them will you know if you get RF noise in your stereo speakers. The stock OEM plug will perform well in most circumstances. I understand that you've already paid for these so get them a go or ship them back for replacement. Go with the NGK IR plugs if you can budget them.

Most plug wires these days already have all the noise resistance you need. I use non-resistor in mine without issue.

Right, so what attributes do non-R plugs have that make them desirable for our old engines? Are they less resistant to fouling? Will they save the planet

Edited April 30, 201014 yr by Gary in NJ

Yes, they save the planet.

There is no difference in performance, only price, if that. As the article from NKG said, the resistored plugs are needed only for computer controlled cars. Ours, obviously, ain't.

Heck, I'm happy if the place carries NGK plugs, period. AutoZone & Advance around here don't.

The only electronics you have is a stereo (assumed to be an aftermarket unit).

And if it's not an aftermarket unit it's not even a stereo; the original Hitachi AM/FM mono radio in my '72 has three pushbuttons for AM preset stations and two more for the fancy new FM stations. The poor early 240Z guys had AM only.

What is remarkable to me, however, is that the radio actually has an integrated circuit, not just transistors.

On a related note. Any NGK"R" plug I have ever put into any running motor I have had to push home at some point. Everything from my ATV, my dirt and street bike, my snowmobiles, lawn mower, I have had to push home because of plug failure. They fail prematurely and I will NEVER put another R plug into anything I own. I'd put in a champion plug first! Now, a non NGK"R" plug, IF you can find them, are the best!

Edited May 1, 201014 yr by IdahoKidd
added "R" in original text

I've NEVER had an NGK plug fail me. But on the other hand, I have actually had to push my datsun out of an intersection because I made the very dumb mistake of using Bosch plugs. Never again, in ANY of my vehicles.

But to each his own.

Dave

I just ordered a tune up kit for the 240Z from Motorsport too, but they sent me the resistor version on the NGK plugs. I've never had any problems with the NGK's, they always worked great for me.

I got plugs for the 280ZX as well. For some reason they came in that smaller socket size.

Heck, I'm happy if the place carries NGK plugs, period. AutoZone & Advance around here don't.

Must be different in this part of the country. I have no trouble getting NGK plugs at any of the local parts places. Advance, O'reily's, etc.

In fact when I replaced the plugs in my Chevy last year the only plugs Advance Auto had in stock for that vehicle were... NGK.

The FSM for my 1978 Z says there are standard spark plugs and HOT plugs? What is the difference between them? Why use one over the other? They also mentioned cold plugs.....hmmmmmm whats up with them?

Thanks