My 1969 327 cu. in. engine uses AC 44 spark plugs which have not been available for years (unless you find New Old Stock on the internet). A year ago, I bought AC 45S plugs at Auto Zone. I went back recently to get more AC 44S or 45S plugs at Auto Zone and was told that they no longer sell the 44S, 45S or the 46S. I'm not sure what's going on with ACDelco. Can anyone explain or tell me where I can buy these plugs? Or can anyone tell me where I can find a chart that shows the conversion from AC to Champion? Thank you.
http://www.ebay.com/sch/i.html?_nkw...geo_id=10232&keyword=ac+44+spark+plugs&crdt=0 Just an FYI, note some of the sellers say reproduction in the ads.
I run ac R44 XL in my hawg. The S and the L and the XL stand for reach, short, long and Xtra Long. The R stands for resister plug for use with electronic ignition. of note they come two ways with ribbed insulators and with smooth insulators, the ribbed insulators are what you want if you can get the guy to look for 'em.
Here is a Champion plug that crosses to the 44 ac plug: A/C DELCO - PART #44 SPARK PLUG - PART #841 Plug Type: J8C Seat Type: Gasket Hex Size (Inch): 0.813 Hex Size (MM): 20.65 Thread Size (Inch): 0.551 Thread Size (MM): 14 Thread Reach (Inch): 0.375 Taper Diameter (Inch): 0.25 Installed Height: 2.24 Gap (Inch): 0.027-0.033 Gap (MM): 0.69-0.84 Center Electrode Diameter (Inch): 0.1 Center Electrode Material: Nickel Copper Alloy Ground Electrode Material: Nickel Copper Alloy Classification: Champion Copper Plus Small Engine Resistor Plug: N But I don't have my Champion book here and went off their website. So then I put in 1969 327, and this is the plug they show: COPPER PLUS - PART #14 Plug Type RJ12YC; Gap .036; OE Type | Per Vehicle Qty: 8 That number looks more familiar to me. Don
Don -- You're absolutely right. I found some old Champion j12yc plugs in a drawer. I notice they don't have the R in the number but I think the R stands for resistor, so it probably has no impact on the heat range or plug operation. I notice some of the plugs have a T designation on them. Do you or anyone else know what T stands for? Could it possibly stand for tapered as in Tapered plug versus a flat plug? Thank you.
Can anyone confirm AC plug designations for hot versus cold plugs. In other words are the higher numbers for hotter plugs and the lower numbers for colder plugs? I can't find that info on the internet. Thank you.
I might be wrong here, but read the full post. Normally the R means Resistor/Radio protection, it has nothing to do with the type of ignition you are running, it allows people around you to listen to radio with you driving by, it also lets them watch TV, for those who doesn't got cable. Because otherwise it will give them interferers. But since most people got a Cable or the like of, and most Radio signals at digital, it's less of a problem. It most important with FM signals, and I believe you mostly uses AM. So it might not mean that much to run them with out the R. And going by the ES or S short, sometimes you can run the a long plug, it comes down to do you have the room for them. And then find the right glow value. But take this from a guy that mostly runs Bosch and NGK in place of AC and other of continent brands. We run them differently, because we want them from the shelf, and not the ones than comes in next week. I've spend the longest time going true "translation"charts to find a good match for a 265, a flat head 100hp 21 stud and for my Volvo to get the best match, performance and availability.
You may have me there, but I never noticed the R plugs until about the time of electronic ignition and everything I have ever worked on with electronic designated resistor plugs where as all the cars prior to electronic didn't designate resistor plugs so I just made that assumption. Someone asked about heat range. normally a higher number designates a higher heat range. At least I have not run into it differently in my time. I will not say absolutely a higher heat range because if I do someone will know of a plug that is different. The T probably does stand for taper, that is easy enough to find out without ever asking, just look at two plugs one with the T and one without. If the t plug is a taper plug and the one without had a gasket (washer) then you are golden. On modern plugs like Nitto or Bosch it may also stand for Tungsten. LOL
How does one know if he needs to step up or down a heat range from whatever plug he's running? The only thing I remember is my dad telling me "number 7 burns a little oil so step up one number to keep it clean longer"
yup 19302739 but there is a change up coming and it looks like it will change to a R44T. ( I am a GM parts tech)
the 44s changes to a r43s the 45s changes to a r45s the 'R' is resistor the 'S' is extended tip on Delco plugs heat range (2nd digit) cold 0-1-2-3-4-5-6-7-8-9 hot
It depends completely on your tune. I have gone with hotter plugs in engines that run a little fat. With a carb sometimes you have to run them a little fat at idle and low to mid range to not starve them on top end. Sometimes too much cam will require a hotter plug as well as it has the same effect until it hits its sweet spot. On most of our engines given that it is not worn out a stock heat range plug will suffice. I hope that helps you a little bit.
Thanks for the calcification Mr. beans. Since I just build my stuff to drive on the street, I never bother with the fine tuning down to the nats ass performance. As long as it runs decent, good enough for me. I have re-jetted my carb before, but never done any real "tuning" as long as the plugs look decent and it doesn't ping I'm good with it.
They were all Chevy plugs silly, is there anything else? I used to prefer Champion plugs until they went off shore. I am a funny old goat, I prefer ACs in a GM and autolights in a Ford. My Cro Magnon intellect makes me think that they work better that way. I have worked on vehicles that needed them indexed, and even changed to hotter or colder from one day to the next. Even played with different gaps and longer or shorter reach to see if we could gain an Nth of a pound foot of torque or a .0001 of a second between point A and point B. Today I look back at it and wonder what I have to show for it. I do still run hotter plugs in town then on the highway in my air cooled engines. I keep my engine tuned for highway running @ a given speed with a little bit extra incase I want to break the rules. I have discovered that it is easier to change the plugs then to rejet so if I am just hopping around town for more then a day or two I throw one heat range hotter in my engine. But that is just a habit I got into a long time ago and it works for me so I just do it that way. Probably has no bearing on this thread though.
Not long ago I bought AC R45TS plugs from NAPA that had a $10 rebate. Cost $10 and change for eight plugs. Thats a good deal any day.
I used these with 350 with '69 heads ran great and had better header clearance actually made the cam lope smoother and used less gas: http://www.jegs.com/webapp/wcs/stor...ponse=submitMMYCmd&storeId=10001&YEAR=1553396 After using them in that Chevy I have used them in several other cars.
JeffB2 -- Thanks very much. I found the plugs you mentioned on the Jegs web site. Yes, they seem like a good way to go for those who prefer using AC spark plugs. Thank you for commenting.
R43S and R45S are both available thru NAPA still with the R45S being the hotter of the 2. Also the R45T is available from NAPA.
On this topic does anyone know if there is a application guide available online. I got a bunch of nos plugs t a swap meet and I'd like to know what they fit.
I have never had good luck trying to run regular Champion plugs in a SBC, they would start missing within 100 miles every time. I would leave my old AC plugs in before changing to Champion. Now Champion gold paladium plugs is a different story, I used them all the time when racing motorcycles.
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