AC Delco R44 Spark Plugs - Obsoleted?

[Bob S.]

It appears that AC Delco has obsoleted the R44 spark plug. (I checked at my local Advance Auto store and then the AC Delco website.) Has anyone else run into this? The R45's in my stock '66 L79 look a little too hot. (I've only had this car for 2 months and haven't looked for R44's for over 20 years since selling my last midyear.)

Does anyone know a source for the AC R44? What plugs are others running successfully? Equivalent plugs of other brands? Are others ok using the R45?

Also, what about equivalent platinum tip plugs?

Thanks,
Bob S.

[Craig S.]

Re: AC Delco R44 Spark Plugs - Obsoleted?

Bob - I am pretty sure the R44's (as well as 44's for sure) are discontinued. I have purchased sets at swap meets such as Carlise and Bloomgington however, without too much trouble. I am not sure about substitutions. Seems like Duke suggests the 45's anyway to stop plug fouling if I recall, are you sure they are running too hot? It is sometimes harder to read plugs with the unleaded these days......Craig

[Charlie P.]

Re: AC Delco R44 Spark Plugs - Obsoleted?

There are usually tons of them on ebay.

[Duke W.]

Re: AC Delco R44 Spark Plugs - Obsoleted?

Don't know how you are concluding that heat range 5 is "too hot", but it's the best for normal street and highway driving for all SBs regardless of power rating. Heat range 4 fouls out fairly quickly in normal driving. Heat range 3 works well for race track hot lapping.

Duke

[Joe L.]

Re: AC Delco R44 Spark Plugs - Obsoleted?

Bob------

The AC R-44 spark plug, also known as GM #5569993, was discontinued in April of 1990 and replaced by the R-43. So, the R-44 has been gone for a long time.

[Roy B.]

Re: AC Delco R44 Spark Plugs - Obsoleted?

I have the early R44's in my 55 Corvette for over 20 years, YES 20 years , I use a plug blaster once a year to clean them and the vett runs great. I also have many NOS plug if I need them.I also run a spray of WATER down the Carburetor at 2500 RPM once or twice a year for a couple of minutes, to keep Carbon build up off the valves, spark plugs and pistons. Some old FARTS know what I mean and do the same thing, while others think were crazy.Unless the pluge show wear WHY change them?

[Joe C.]

Re: AC Delco R44 Spark Plugs - Obsoleted?

It's been a long spell since I done that, mainly because I killed my old yeller bird dawg when a big hunka carbon come a flyin outta the muffler pipe an hit the critter square in the mush. I reckon he took to runnin an a howlin, runnin an a howlin fer darn near 10 minits before he went belly up. All the while the car was a makin a racket like all hell was breakin loose......why, the sherriff even come a ridin in askin where the gunfire was a comin from. I figgered maybe I was a usin hard water, an busted somethin up insider the ole jalopy.

I had to let grandpa get his 2 cents in, but the procedure does work, trust me. You just need the guts to try it. Also, go easy, it does put lots of stress on the combustion chambers.

[Clem Z.]

brass chain better than water???

i have a really old car book and they say to put a short section of brass chain into the cylinder thru the spark plug hole and start the engine to let the chain loosen up the carbon. let me know how it works.

[Don H.]

Re: AC Delco R44 Spark Plugs - Obsoleted?

I run R-45's in my '60 w/F.I. and they work fine. Don H.

[Joe S.]

Re: AC Delco R44 Spark Plugs - Obsoleted?

I have a brand new set of 44's still in the box if anyone is looking for them. EMail me with an offer.




Joe's 63 FI Convertible

[Joe L.]

Re: AC Delco R44 Spark Plugs - Obsoleted?

Joe------

These are AC 44 plugs and not the AC R44 that was the subject of the original thread. The R44 plugs are the resistor type plug used to reduce radio interference. They were first used for the 1969 model year, although they can also be used for earlier models, as well. The 1966 car that Bob has, though, was not originally equipped with resistor-type plugs although thats, apparently, what he's been using.

[Roy B.]

Re: brass chain better than water???

CLEM I think that chain idea was written in Air-a-bick

[Bob S.]

Re: AC Delco R44 Spark Plugs - Obsoleted?

Thanks for all the great input. I think Duke hit the nail on the head. The last time I 'read' any plugs was with leaded gas....I didn't stop to consider how the change to unleaded might affect the appearance. I think I stick with the R45's.

I may even work up the courage to try the water trick that Joe and Roy suggest. But I will leave the brass chain for someone else to experiment with, though.

Regards, Bob S.