SPARK PLUGS

[nmaineron]

Finding non-resister spark plugs is a challenge here. Today I had an appointment in the city and hit up a few auto parts stores, only one of three had anything non-resister and what was interesting was they had an NGK plug, BP7HS, which is in line with the J12Y and Autolite 4275. He brought a plug out that crosses with the NGK and it was an L78YC Champion, which is a marine plug. I don't know what the store has for a cross reference, prolly a master cross, but I've never seen a chart that included marine and auto together. So...will these go in my pan safely?

[Frankenstein]

I just use B6L

[RooDog]

Back in the day we all used Champion J12Y plugs in our Panheads.
They are still available on eBay, will that work for you?

[rocket ron]

Watched this video on YouTube about modifying resistor plugs



Don’t know whether it works as I don’t have a problem obtaining non-resistor plugs for my flatheads.
Ron

[nmaineron]

I just find it interesting that things like this marine plug come up an possibly open up the options a little. I've never had any problem finding plugs until recently. It's been 30 years since I had my 41 and 52 so I haven't had to search. Obviously, if they just had what I asked for, the marine plug wouldn't come into the picture.
Ron, I saw that video, I'm gonna do it.

[RooDog]

I walk into the local neighborhood AutoZone, and the smiling, friendly, and knowledgeable sales person, (of indeterminate gender orientation/identity) asks:
" And what are we working on today?"
My reply is a 1968 Harley Davidson. And it's down hill from there......
What kinda car is that?
....RooDog....

[Mongrel505558]

That's why I buy from Artie's Auto Parts - a local business, not a franchise. Artie and the other guy that work there are knowledgeable and helpful. I have no problem getting plugs from them for my '68. Same with points. I told Arite I needed plugs for an old in-line 6 Chevy. He asked me if they were actually for an old Harley-Davidson and came back with Blue Streak points and condenser. They also have a big cat that hangs around the store. It sits on the cases of oil and looks out the window. The problem with most franchises is if the salesperson can't find it on their computer screen that's the end of it.

[Architect]

Easiest to just buy them from Amazon, 8 at a time. Better than going parts store to parts store and dealing with questions, good luck.

[RooDog]

Easiest to just buy them from Amazon, 8 at a time. Better than going parts store to parts store and dealing with questions, good luck.

If they got 'em. Ain't got no Champion J12Y s listed...

[RooDog]

So, what happens, or doesn't happen if resister spark plugs are used.
Any factual information?
....RooDog....

[nmaineron]

I asked myself the same question, how do the plugs have any affect downstream from the mag? I haven't found much to back up the myth. Course anything out of the bike world is solid on the no resister myth. I found some stuff relating to mag driven air plane ignitions out of WW2 and general aviation and it kinda read just backwards to how we've been thinking. The frequencies from the mags was playing with the instrumentation in the planes. Then there was the occasional biker that ran whatever without any related issues.

[droptopford]

So, what happens, or doesn't happen if resister spark plugs are used.
Any factual information?
....RooDog....

As far as 'factual' information, I can only offer these two facts:
1) Resistor plugs were developed to reduce radio frequency interference (RFI).
2)The 'resistance' involved does reduce the strength of the spark, even if only slightly.

Since none of my old bikes have radios (or any other modern electronic equipment) that might be affected by RFI, there's no reason for me to run resistor plugs. I'll take all the spark I can get.

Can I tell the difference between a set of 'R plugs and non 'R' plugs, all else being equal'?... I can't honestly say. But I suspect some of my bikes have been influenced by the power of suggestion.

[Ratedspeed]

Finding non-resister spark plugs is a challenge here. Today I had an appointment in the city and hit up a few auto parts stores, only one of three had anything non-resister and what was interesting was they had an NGK plug, BP7HS, which is in line with the J12Y and Autolite 4275. He brought a plug out that crosses with the NGK and it was an L78YC Champion, which is a marine plug. I don't know what the store has for a cross reference, prolly a master cross, but I've never seen a chart that included marine and auto together. So...will these go in my pan safely?

The Champ J12Y is a 3/8" reach plug with a fairly hot heat range of 12.
The L78YC is a 1/2" reach plug with a cooler heat range of 7-8.
The 3/8" plug uses about all the threads in a pan plug hole so a 1/2" reach plug may protrude into the chamber a touch.

Mike

[Excalibur]

Logically, when an impedance is added to a high tension circuit, there's more potential for tracking/shorting than if the impedance wasn't there at all.

[beets]

Are the HD 3-4s available at the dealer now? I used to get them in a tune up kit along with points and condenser and these kits are now obsolete.