A/C Spark Plug "Find"?

[Bruce Boatner]

This weekend I was rooting around an old tool supply store looking for some R12 manifold gauges (another story). I noticed several crusty looking packages of "remanufactured" A/C spark plugs. The markings on the plugs varied from R43S to R45S. Couple of questions. Does the "S" at the end mean anything special? Could these plugs be acceptable for judging purposes assuming the "S" is typical and hence worth something, or are they worth only the $4 for a package of 8 the tool supply company was asking for?

Thanks!

[Duke W.]

Re: A/C Spark Plug "Find"?

The "S" means extended tip and they were never used as OE on vintage SBs, but some owners retrofit them. Theoretically they have a wider heat range, so they are more resistant to fouling, and they place the spark a hair closer to the geometric center of the chamber.

On SHP engines the pistons can hit the ground electrode if quench clearance is tight.

A real find would be the AC 44 since they were OE on most if not all vintage SBs from '55 to whenever they began using resistor sparks plugs, which IIRC was about '68, although the markings were different over the years, so any AC 44 is not necessarily NCRS "correct" for all SBs.

Duke

[Mike Cobine]

Re: A/C Spark Plug "Find"?

so any AC 44 is not necessarily NCRS "correct" for all SBs.

But if I remember correctly on here a few months ago, someone mentioned that no one pulls the plug shielding or the plug boot during judging and that pretty well conceals what plug is in there.

[Duke W.]

Re: A/C Spark Plug "Find"?

Nope! You can see the lower part of the insulator that the boot doesn't cover between the heat shields and head, so the numbers and some other graphics on the insulators are visible. Try it! A good flashlight and glasses (for us geezers) helps.

Duke

[Joe L.]

Re: A/C Spark Plug "Find"?

Bruce------

REMANUFACTURED spark plugs? I wonder how someone "remanufactures" a spark plug? I expect that they clean them up with an abrasive bead blast and that's about it. I'm sure that these things are designed for "REAL LOW BUDGET" tune-ups. I don't think that I'd use them.

[Bruce Boatner]

Re: A/C Spark Plug "Find"?

Joe,

I sort of wondered about what steps were taken during the "remanufacturing" process myself. A good analogy may be the "experienced" golf balls for sale.

Considering that the price is $4 for 8 plugs, I guess one can't be too picky. My thinking was someone would be glad to have these for show purposes. Hmmm...wonder how hard it would be to remove that "s" at the end?

Bruce

[Dick W.]

Re: A/C Spark Plug "Find"?

Maybe destined for "Honest Dan, the Used Car Man". Like the traveling vendors selling used batteries, tires, etc to the dealers.

[Joe L.]

Re: A/C Spark Plug "Find"?

Bruce-----

I think that you could find an NOS set of plugs without the "S" suffix a LOT easier than you could remove the the "S" from these plugs.

[Clem Z.]

Re: A/C Spark Plug "Find"?

why would the NCRS deduct points for something that can no longer be made or faked like spark plugs after all this is not something simple to fake like a engine block.

[Craig S.]

Re: A/C Spark Plug "Find"?

Bruce - I agree with Joe, there are plenty of AC 44's around at swap meets, maybe even some of the corvette vendors....you might check with Doc Rebuild...Craig

[Len Rayca]

Re: A/C Spark Plug "Find"?

Someone has some AC44 plugs up for sale on Ebay currently.

[Dave Suesz]

According to GM, they began using resistors in '55

The AMA vehicle specifications I received from Chevy as part of my restoration package includes a photocopy of the ORIGINAL AMA questionnaire with stunningly complete engineering specifications, and the V8 engine park plug specified is "AC 43-5R". I put AC Delco 44R plugs in, and the car has never run so well, or the radio played so well.

[Duke W.]

Re: According to GM, they began using resistors in

Interesting! I'm not sure if "dash 5R" means a resistor type plug, and I don't think I have any documentation old enough to decode it.

There were a lot of different parts in early SBs, but by '57 the configurations had settled down and many parts from that point carried through for many years.

Duke

[Mark S.]

Re: According to GM, they began using resistors in

The 56 plug is the same configuration as the 57 plug; only the 56 initially was a 43. In 57 they went to the hotter plug.

[Joe L.]

Re: According to GM, they began using resistors in

Dave-----

Yes, the plugs used for 1955 were the AC 43-5R and they were a resistor-type spark plug. However, they were not first used for 1955. They were first used for 1953 and that use continued through 1955. They were used ONLY for Corvette applications, though; other Chevrolet engines did not use them.

After 1955, the resistor-type spark plugs were not used again until 1969, at which point thewy were phased in across-the-board for all Chevrolet engines.