Spark plug questions

[Acollin]

After all the tinkering with my carbs and running strong without the dieseling, I took a look at my spark plugs today and had a question or two.
I am using AC R42x LS gapped at .025 or so.
My plug burn is grey in color now and from all my reading on the subject, I would expect there to be some tan in the burn on the plug.

There is no flaking or blistering, but I was wondering:
1) am I running too lean (now that I have eliminated the dieseling)?
2) is this too hot a plug.? Is there a recommendation for plugs — I see the manual recommends champion N9Y
also
3) I noticed that my spark plugs do not have crush washers. Should I have crush washers on my spark plugs?

4) Do I need to bother with the above questions now that I have good throttle response and no dieseling?

If it matters, I use non ethanol 92 octane fuel.
Thanks all
Andrew

 

[Barry]

After all the tinkering with my carbs and running strong without the dieseling, I took a look at my spark plugs today and had a question or two.
I am using AC R42x LS gapped at .025 or so.
My plug burn is grey in color now and from all my reading on the subject, I would expect there to be some tan in the burn on the plug.

There is no flaking or blistering, but I was wondering:
1) am I running too lean (now that I have eliminated the dieseling)?
2) is this too hot a plug.? Is there a recommendation for plugs — I see the manual recommends champion N9Y
also
3) I noticed that my spark plugs do not have crush washers. Should I have crush washers on my spark plugs?

4) Do I need to bother with the above questions now that I have good throttle response and no dieseling?

If it matters, I use non ethanol 92 octane fuel.
Thanks all
Andrew

Your S-V engine left the factory with an alloy cylinder head designed to use flat-seat spark plugs with a metal gasket. Unless your cylinder head has been modified to use tapered-seat spark plugs (unlikely), you should be using flat-seat spark plugs with a metal gasket.

Among other things, failure to use the metal gasket on flat-seat spark plugs puts the spark plug too far into the combustion chamber and does not ensure a proper seal.

None of your other questions are relevant until you have addressed the spark plug gasket issue. The metal gasket on flat-seat spark plugs cannot typically be easily removed, so ?????

 

[Acollin]

Thanks Barry.
They are tough to remove!
Do you have a recommendation as to which plugs to use — with the gasket in place?
what would the effect be on the color burn of the plug without a gasket? Would you expect it to burn hotter?
Thanks again
Andrew

 

[gatkeper1]

After all the tinkering with my carbs and running strong without the dieseling, I took a look at my spark plugs today and had a question or two.
I am using AC R42x LS gapped at .025 or so.
My plug burn is grey in color now and from all my reading on the subject, I would expect there to be some tan in the burn on the plug.

There is no flaking or blistering, but I was wondering:
1) am I running too lean (now that I have eliminated the dieseling)?
2) is this too hot a plug.? Is there a recommendation for plugs — I see the manual recommends champion N9Y
also
3) I noticed that my spark plugs do not have crush washers. Should I have crush washers on my spark plugs?

4) Do I need to bother with the above questions now that I have good throttle response and no dieseling?

If it matters, I use non ethanol 92 octane fuel.
Thanks all
Andrew

R42XLS is considered a cold plug. It is correct for a SV engine. Some plugs come with the gasket loose in the box. If there is no metal crush ring on the plug , someone might have installed the plugs without them. You're not going to be able to buy them ,you will need to buy new plugs. N9Y is equivalent to the plug you have, New number is 415 Champion aka RN9YC. Plug color charts are largely irrelevant as todays fuel colors /discolors the insulator differently. Do not run that engine with out those gaskets on the plugs

 

[Acollin]

Thanks gatkeper1– I won’t run my car - ANYMORE - without gaskets in place.
Have I done any damage by running the above plugs without the gaskets? Is it a plug length issue? There is no damage to the plug so there was at least some clearance and since doing the carb stuff the car has never run better.
Heading to the auto parts store for new plugs.
Many Thanks

 

[Barry]

Thanks Barry.
They are tough to remove!
Do you have a recommendation as to which plugs to use — with the gasket in place?
what would the effect be on the color burn of the plug without a gasket? Would you expect it to burn hotter?
Thanks again
Andrew

Spark plugs should not be tough to remove. You should always use anti-seize on steel threads in an aluminum alloy head and I would not be surprised if whoever left out the spark plug gaskets also did not use anti-seize.

I prefer NGK spark plugs because I think they are easier to "read" (both mixture and timing) than other readily available brands. A NGK BP6ES is equivalent to the Champion N9Y that is listed in the WSM (and to the AC R42XLS).

 

[hartmandm]

N9Y is equivalent to the plug you have, New number is 415 Champion aka RN9YC.

With the leading "R" in the part number, the Champion 415 should be a resistor spark plug. Champion 300 is the current part number for N9Y (non-resistor) and what I have in my SV.

Mike

 

[gatkeper1]

With the leading "R" in the part number, the Champion 415 should be a resistor spark plug. Champion 300 is the current part number for N9Y (non-resistor) and what I have in my SV.

Mike

Resister plugs were first used in 1969. I'm fairly certain Rootes would have used them if they were available for the SV when they were produced. Resistor plugs or suppressor core plugs are in everything today even lawn mowers. Its not an issue. Now as far as N9Y. I believe what you are buying today is not what came in your engine. N9YC / 300 is what I believe all you can find unless you have a source for NOS N9Y plugs . The new number replaces both N9Y and N10Y, yes 2 heat ranges, because they use copper cores today and has allowed the plug makers to consolidate their plug lines. Now that I have said that. When I go to judged shows with my GT350, I will put my NOS Autolite BF32 non resistor non copper plugs in it. They have not been made in over 35 years. Run what ever plug, as long as it fits the application. Personally I use Bosch or NGK. I don't even put Champs in my lawn mower

 

[Tim R]

Has anyone got any experience of running Iridium Spark Plugs? Lots of claims are made for them, are they worth it.

Tim R

 

[Barry]

Has anyone got any experience of running Iridium Spark Plugs? Lots of claims are made for them, are they worth it.

Most if not all U.S. OEM gasoline-powered vehicles use Iridium spark plugs because of the federal mandate that the emissions system has to be good for 80,000 miles. The Iridium plugs will generally last well over 100,000 miles.

 

[husky drvr]

Iridium Spark Plugs

Tim,

It's probably best to figure out how often and why you are needing to adjust or change plugs. Is it due to worn electrodes giving a weak spark or combustion byproducts that foul the plug interior and bleed down the energy available to energize the spark. If the latter, iridium plugs might not last much longer than your regular plugs. Gives an answer of "it depends on your situation" or YMMV.

The only way to know is to try.

Hope this helps,

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiIz9fgp_j-AhW6kYkEHbLsCgUQFnoECAYQAw&url=https%3A%2F%2Fwww.championautoparts.com%2FParts-Matter%2Fautomotive-repair-and-maintenance%2FSpark-Plug-Materials.html&usg=AOvVaw0fYvNu743M2RbGRRkasyse

 

[Acollin]

As always, I learned a great deal and as always, more questions arise.

I used those photos in Haynes books for years to assess what was going on in my cars.
Question: is there anything to learn from looking at your plugs if fuel is a major determinant in the coloring of spark plug burn.? If a tan plug is no longer the desired effect, what now is?

I assume black , sooty , wet and dry are still telltale factors, but what does one want to see when you assess your spark plug burn after a few hundred miles? Was my grey, no burning or pitting adequate?
Andrew

 

[Shannon Boal]

OK, reading plugs.....run at highway speed 15 or 20 miles. Cut it off, declutch and coast into a shady spot.
Mixture, read the shell; (end of the threaded portion) light to medium gray desired
heat range, looking at porcelain insulators for light tan to almost white.
I like long nose plugs, am running Autolite 985 at 0.045". These things stick into the chamber an extra 3/8" or so. They also use a 5/8" socket instead of 13/16".
If there is fuel or oil fouling, (black soot or wet oily deposit that fills up the inside of the plug) I like hot plugs. I have never found them to cause spark knock, dieseling or anything, your mileage may vary....
I am testing Delco R46xls

 

[Scotty]

I run Autolite XP63 Irridiums. I use them because supposedly they last and they have a resistor which I guess you're supposed to have if you got electronic points like I do. They're also the ones you can walk into damn near anyplace and buy with no issues, but since they're damn near $7 apiece where I live, you damn well should be able to.

I run the log manifold so both 'center' ports (2 and 3) mixture-wise are dead on and the 1 and 4 ports are running abit rich. I'm terrified to run them lean.

Frankly, I've never noticed any difference between running them, Copper 63's, NGK or whatever have you. I've ran a handful of different plugs, all with crush washers (Never had any that didn't come with them) and anti-seize. I had my Weber 32/36 running abit too rich and was swapping out plugs until I found the sweet spot where it likes to be. I still think it runs rich but I change my oil abit more than many do (I'm a paranoid bastard), so I'll live with it for now.

I half-expect the Irridiums to last the life of the engine.

 

[Scotty]

As always, I learned a great deal and as always, more questions arise.

I used those photos in Haynes books for years to assess what was going on in my cars.
Question: is there anything to learn from looking at your plugs if fuel is a major determinant in the coloring of spark plug burn.? If a tan plug is no longer the desired effect, what now is?

I assume black , sooty , wet and dry are still telltale factors, but what does one want to see when you assess your spark plug burn after a few hundred miles? Was my grey, no burning or pitting adequate?
Andrew

If you take the car on short trips, those readings will fool with you.

 

[Tim R]

Scotty,
If you get the chance fit the curved inlet manifold (Alpine Innovations sell it). It will make the biggest change to your car that you will ever experience. Instead of having two cylinders not giving their all you suddenly get all four pulling their weight equally and it absolutely transforms the car.
Tim R

 

[Mike O'D]

I'm running the Autolite XP63s also - for about a year now. $4.55 each from Rockauto Scotty. Can't say I noticed a difference from the regular Champions. I haven't pulled them out and looked at them since installing them.

 

[husky drvr]

I'm running the Autolite XP63s also -

Mike,

Just a curiosity question - RockAuto's site specifies the XP63 plugs are gapped at 0.032 inches, did you reset or install as supplied?

Even if running the OE points ignition, using the wider gap might be beneficial with these plugs.

Just a thought,

 

[Mike O'D]

Don,

I left them as received. I think it would be tricky to re-gap them with how thin that electrode is. I'm running a Pertronix distributor, just FYI.

 

[Jay Laifman]

FWIW, I've always understood that the platinum and iridium plugs exist now, and work well, with modern cleaner engines. But that they foul faster in older dirty engines (aka our engines).