Spark plug question ???

[davids2toys]

While doing my valve cover gaskets, I notice how much easier the plugs looked like they would be to change without the valve covers installed.
I pulled a plug out, it is a Champion RF91C, it seems to be burning good...I have no idea how old they are, or if they are even the right plug.
I have a 428, with CJ heads, MSD box.
What would be the correct plugs for this engine...also, what should the gap be.
I did search but only found small block info!

[Naumoff]

David, Are those RF9YC? They are correct.

Motorcraft BF-32/ Resistor BSF-42C
Autolite 35 or 34/ Resistor 45 or 44
Champion F11YC or F-9YC /Resistor RF-11YC or RF9YC
Accel 378 /Resistor 675


Points distributor Gap 35
Electronic distributor Gap 44

If you are looking for performance you want to use non-resistor spark plugs. A resistor is exactly what the word implies. When the spark crosses the point of resistance some of the spark energy is lost. A resistor is like an electronic obstacle and could be the cause for a weak spark. Non-resistor spark plugs deliver a more powerful spark.

[davids2toys]

David, Are those RF9YC? They are correct.

Motorcraft BF-32/ Resistor BSF-42C
Autolite 35 or 34/ Resistor 45 or 44
Champion F11YC or F-9YC /Resistor RF-11YC or RF9YC
Accel 378 /Resistor 675


Points distributor Gap 35
Electronic distributor Gap 44

If you are looking for performance you want to use non-resistor spark plugs. A resistor is exactly what the word implies. When the spark crosses the point of resistance some of the spark energy is lost. A resistor is like an electronic obstacle and could be the cause for a weak spark. Non-resistor spark plugs deliver a more powerful spark.

I would like to replace the champions with autolites because I have heard they are much better...every thing cross referances back to a Autolite resister 45, there is no such thing as a 44, at least not any more. There are no straight champions either, just resister. Believe it or not, the difference in champion RF11yc and RF9yc is the thread, I thought it would be the heat range!!!
Autolite does make a non resister but it is a racing plug, I think the numbers started with AR
I ended up buying R45's, but not sure if I should put them in.
What do you think about the racing autolites?
The Champion RF9yc I took out looked like it was burning nice, I dont want to end up with a problem, especially because it looks like you need to remove the valve covers to get the plugs out!!
Also, would you know the torque on the plugs, and I will be using a tiny bit of anti-sieze, unless that is a no no to...lol.

[Naumoff]

Just guessing but it might be getting harder to find a variety of those pugs for the original CI heads. R45 should be fine.
I would run the racing plugs but that might just be me.
Here is a link to torque specs and aditional info.
http://www.autolite.com/pdf/TorqueSpecs.pdf

Installing Spark Plugs Without a Torque Wrench

14 and 18mm tapered seat plug – tighten 1/16 turn after finger tight;
14 and 18mm gasket seat plug– tighten 1/2 turn past finger tight;
12mm gasket seat plug – tighten 3/8 turn past finger tight;
10mm gasket seat plug – tighten 1/4 turn past finger tight.

NOTE:

Spark plugs should be installed with clean and dry threads to avoid overtorquing or stretching

the spark plug which can, and often does, result in engine damage


I have changed my plugs with the valve covers on but if you have them off it is easier. I use a swivel spark plug socket with a long extension. Same thing we use on big block 67 - 70 Mustangs and Cougars.

Racing plugs are colder.

I found this info on the web,

Keep in mind the insulator nose length is a determining factor in the heat range of a spark plug, the longer the insulator nose, the less heat is absorbed, and the further the heat must travel into the cylinder head water jackets. This means the plug has a higher internal temperature, and is said to be a hot plug. A hot spark plug maintains a higher internal operating temperature to burn off oil and carbon deposits, and has no relationship to spark quality or intensity.
Conversely, a cold spark plug has a shorter insulator nose and absorbs more combustion chamber heat. This heat travels a shorter distance, and allows the plug to operate at a lower internal temperature. A colder heat range is necessary when the engine is modified for performance, subjected to heavy loads, or is run at a high rpm for a significant period of time. Colder spark plugs remove heat quicker, reducing the chance of pre-ignition/detonation. Failure to use a cooler heat range in a modified application can lead to spark plug failure and severe engine damage


http://www.ngksparkplugs.com/techinf...000&country=US

[davids2toys]

Just guessing but it might be getting harder to find a variety of those pugs for the original CI heads. R45 should be fine.
I would run the racing plugs but that might just be me.
Here is a link to torque specs and aditional info.
http://www.autolite.com/pdf/TorqueSpecs.pdf

Installing Spark Plugs Without a Torque Wrench
14 and 18mm tapered seat plug – tighten 1/16 turn after finger tight;
14 and 18mm gasket seat plug– tighten 1/2 turn past finger tight;
12mm gasket seat plug – tighten 3/8 turn past finger tight;
10mm gasket seat plug – tighten 1/4 turn past finger tight.

NOTE:

Spark plugs should be installed with clean and dry threads to avoid overtorquing or stretching
the spark plug which can, and often does, result in engine damage


I have changed my plugs with the valve covers on but if you have them off it is easier. I use a swivel spark plug socket with a long extension. Same thing we use on big block 67 - 70 Mustangs and Cougars.

Racing plugs are colder.

I found this info on the web,

Keep in mind the insulator nose length is a determining factor in the heat range of a spark plug, the longer the insulator nose, the less heat is absorbed, and the further the heat must travel into the cylinder head water jackets. This means the plug has a higher internal temperature, and is said to be a hot plug. A hot spark plug maintains a higher internal operating temperature to burn off oil and carbon deposits, and has no relationship to spark quality or intensity.
Conversely, a cold spark plug has a shorter insulator nose and absorbs more combustion chamber heat. This heat travels a shorter distance, and allows the plug to operate at a lower internal temperature. A colder heat range is necessary when the engine is modified for performance, subjected to heavy loads, or is run at a high rpm for a significant period of time. Colder spark plugs remove heat quicker, reducing the chance of pre-ignition/detonation. Failure to use a cooler heat range in a modified application can lead to spark plug failure and severe engine damage


http://www.ngksparkplugs.com/techinf...000&country=US

Great info, thank you!!!
Do you know which size I have?

14 and 18mm gasket seat plug– tighten 1/2 turn past finger tight;
12mm gasket seat plug – tighten 3/8 turn past finger tight;
10mm gasket seat plug – tighten 1/4 turn past finger tight.

or how I can tell?
So which Autoliter racing plug would you run, knowing thay the RF9YC was burning good? Is there a downfall to using the racing plug!

[Naumoff]

Probably 7/8" close to 18mm

Accel 378 did you try to find them?

Your on the street and the plugs look fine at an idle so running a colder plug would be fine. which is what racing plugs will be.


I have aluminum heads so my car takes a different sparkplug.