Do you gap all plugs the same?

I put a set of Champion RN14MC5 plugs in the '71 last year when I first brought it home, along with a new set of wires. Don't know where I heard of this plug, although it may have been on here. The car has been running quite good with them though, once I got the points and condenser issue corrected. On these plugs, I have the gap set at .25... Again, I either read it here or in a book, but I also have a brand new set of NGK BPR6ES at home which I would like to try out.
Doing a search here, the common gap for the NGK's seems to be .35, but I also notice that a lot of folks using these plugs also have electronic ignition.
So, is the gap I have been using for the Champion's too narrow, and should also have been at .35? And, is .35 good for the NGK's using points and condenser?
What would running the Champs at .25 done to the performance of the engine as well?

Thanks

Paul

Electronic ignition, .035. Points .025. Stay away from the NGK's.

JackMG Wrote:

I hate to differ with my jam connection, but all I ever used is NGK. But I agree with Jack gaps based on points or electronic.

NGK's aren't made for the same temp range as the Champs and I've had problems with them misfiring. Others here seem to be happy with them. I think N9Y(+C for copper) were the last Champs I used. I recently put Bosch Platinums (can't recall the #) and they seem to be doing just dandy.

Accel or NGK is my choice.

I must admit I haven't tried NGKs since soon after they hit the US market back in the early 70's. I put a set in my MGA and the car immediately developed a miss when it got hot. Fiddled with them to no avail and then I bought a new set of Champs and it ran fine again. Haven't been inclined to try NGK's since. IMHO, I just thought it was part of the syndome of "everything Japanese is better than anything American" - a myth that the folks born in the 50's and 60's seemed to perpetuate ;^) Always had good luck with the C's - especially after they came out with the copper electrodes - lasted a very long time and performed as well as a plug can.

If you run an uprated coil such as Lucas Sport, widen the gap to around .032. .035 would be as far as I would go with any setup.

Do you know what the gap is for??

The larger the gap, the larger the spark. In order to get the most efficient burn in the cylinder you want the hottest biggest spark possible.

But, each iginition system is different. And if you gap a plug too large for a given ign. system, you'll get NO spark. If you gap them too close, you get a weaker spark.

So it's a fine balance!

I generally do what the manufacturer suggests for that particular plug and then I cross reference that to what the maker of the car suggests. They're usually the same.

Since some plugs are different though, I would tend to do what the plug manufacturer said, rather than the car manual. An example of this would be the Bosch Platnums, they're usually a different gap because of the different design characteristics.

Brian

Typically the electronic ignition systems produce voltage high enough for .035, whereas the stock (earlier) points style systems will produce around 8-10,000 volts less, requiring a closer gap to ensure reliable spark.

IIRC, standard coils are 10-20,000 volts. Sport coils are 30-40,000 volts. I haven't heard that EI systems produce more voltage than points, just that the timing is more precise. Is there more to it?

Sport coils are generally the types used with EI systems, standard coils with points. Using sport coils with points will somewhat shorten the life of the points because of increased current. I have the coil from an EI on my car and recently put a points dist in it because of problems whith the E in the EI. It works fine so far and the plugs are still at .035. But I do expect shorter point life.

I have tried both .030 and .035 in mine with uprated coil and pertronix, I can't tell the difference in the two, currently running .030.

I've been running a sports coil in my B for many years. I've only replaced the points once and it was right about on time. Maybe it has to do with the condition of the rest of the ignition system, plug wires, etc?

I ran Champion's in my MGB once 20 years ago...switched to NGK's and have never run anything in the MGB or TD but NGK's....

Hey Klutz, you did a typo stating .25 not .025(correct). .25=1/4" don't quite need that much gap eh!

berngp Wrote:

I run as sports coil and points with Bosch plugs. Burgess says .025 for a standard coil and .028 for a sports.

I agree with the other Steve S (and 2 Steve S's can't be wrong),the electronic systems should have no effect on the spark strength unless you have bad points or you are taking about a fancy capacitive discharge system.

Has anyone tried the Bosch plus 4's? I found a number that isn't listed or the MG but is listed for the Jetta. The Jetta uses the same plug as the MG in a Champion, but I wonder why the Plus 4 isn't shown for the MG. I used the plus 4 pugs in a 350 and there was a noticeable difference, hoping for the same on my MGb ( 18V). Any thoughts?