View Full Version : Spark plug for '56 President 289 V8?

01-24-2007, 12:29 AM
Which spark plug should I use for a rebuilt 6 years ago (never run, just hung outside) '56 President 289 V8? I think the manual calls for a Champion H11 which isn't made anymore.
www.napaonline.com calls for a Champion RH18Y (#857)
www.advanceautoparts.com calls for a Champion RH10C (#854)
www.autozone.com calls for a Champion RH10C (#854)
Which is it? And why are they different?

[img=left]http://www.bulletshots.net/images/stella3.jpg[/img=left]1951 Commander Starlight Coupe (aka "Stella")

01-24-2007, 12:36 AM
All will work, I use the 18YC's. They are mostly just tip length differences.

64 Commander 2 dr.
63 R2 4 speed GT Hawk (Black) #2
63 Avanti R1
63 Daytona convert
63 Lark 2 door
63 Lark 2 door #2
62 Daytona HT/ 4 speed
62 Lark 2 door
62 GT Hawk 4 speed
60 Lark HT
60 Hawk
59 3E truck
52 Starliner
51 Commander

John Kirchhoff
01-24-2007, 10:05 AM
With Champion plugs the larger the number the hotter the plug runs. I think I have 14's in my two cars which is believe is closer to the middle of the road. A lot depends upon the load conditions the car runs under.

Run too hot of a plug (a higher number) and under conditions of high ambient air temp entering the carb (or pressurized air from a super or turbocharger), high coolant temps, heavy loads and especially is the fuel mixture is on the lean side (those mixtures burn hotter than ones too rich) and the tip of the plug stays so hot that the heat from it alone can ignite the cumbustion mixture as the piston comes up on top dead center. This causes pre-ignition and the pinging it causes is the least of your worries. Severe cases will melt holes through the piston and mild cases will blister the porcelain on the plug tip and melt the metal electrode. Be cautious because pre-ignition can damage something in the blink of an eye if severe enough.

Run too cold of a plug and the plug tip stays so cool that it isn't able to burn off carbon when running extra rich mixtures such as on start up before the engine is warmed up and the choke fully open. Get a large enough accumulation of carbon on the plug tip and it conducts some of the electrical charge to the ground resulting in a very weak spark or no spark at all.

Most modern Champions have a "C" in the designation anymore. What used to be a N3 is now a NC3, the C standing for a copper electrode (the tit on the end of the plug that's surrounded by porcelain. I don't know about auto manufactures, but since class action suits came about, motorcycle manufactures call for plugs that are most definately on the cold side. That way when some pimply faced kid whacks open the throttle and leaves it that way for 10 miles, the odds of the plugs causing pre-ignition is just about nil. On my bike I've found the next heat range higher works better for my style of riding. Too cold of a plug and cold weather starting and running is affected.

As far as the plug goes, if you plan on average driving I'd probably go with at least a 12 or 14 but if it's putting around in Christmas parades, you might look at the 18. It might be best to see what others are running, but for some reason I get this funny feeling the 18 is a little too hot. Call me crazy, but I'll put it this way, I wouldn't run it in my cars.

For some reason I seem to remember that a good number of years ago Champion reshuffled their heat range numbers. I can't remember if they moved them upwards or if that's just a figment of my imgination. Better to listen to folks who know more than me.

01-24-2007, 11:09 AM
Autolite 437 It's the Autolite cross reference for the H-14Y Champion which is no longer made but WAS the primary non-R-series plug forever on Stude V8s.:D

Miscreant adrift in
the BerStuda Triangle

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe

Dwain G.
01-24-2007, 11:36 AM
The H-10's that the other two stores list are incorrect for a President. They are a much colder plug intended for supercharged engines with (supposedly) higher combustion chamber temperatures.

Dwain G.
(We're not called 'hillbillies' any more....we're now Ozark Americans)!