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Colder plug/Hotter plug & engine detail sticker question


our51super
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I was told that for our 51 Super the AC Delco plug was a "44". This plug is no longer manufactured so I was told by the people at a specialized Buick parts place to use a "43" ( a colder plug). I then called a local parts store and they told me that I probably want to go to a "45", (a hotter plug). The local parts store told me that a hotter plug will burn more efficiently and comletely than a colder plug (makes sense to me). I am wondering however if the hotter plug will cause the engine to run hotter (don't want to go through that again) and also why did the specialized Buick parts place recommend a colder plug?<P><BR>The second question I have is in regards to engine detailing deals. I have received an engine detailing decal set and I have an "F263" circular decal and a decal that states something like 'this engine equipped with hydraulic lifters' and I don't know where they go.<P>Thank you in advance.

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44 is no longer made????? must have happened in the year or 2. if a 43 is available and a 45 is available it strikes me as odd that the 44 is discontinued???? Better check with AC DELCo customer service to be sure. Pay NO ATTENTION to those auto parts stores. They try to sell their slow movers to people like us because they think we rarely if ever drive these cars. When choosing a plug heat range it is best to error slightly hotter than colder. The plug life mite suffer but its not like they cost $1.20 gal either. If the plug gets too cold it will stumble alot at low speeds. Too hot and spark knock will occur(maybe). For nearly all 'normal' operation for nearly any engine the 44 (regardles of prefix or suffix) is mid heat range and should be just fine. The 45 or 43 is ok too. <BR>IN ANY EVENT. DO N O T let parts stores talk u into some other brand of plug.

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All the tune up charts I have seen ,list either the AC46 or AC48 for straight eight Buicks. The are hard to find ,but the AC 44 is used in LOTS of V8s and is readily available in this area. I run AC46 in my straight eight and have put over 94,000 miles on it and it still runs GREAT ! smile.gif" border="0

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Guest Howard Purvis

Re: "F263"<P>If my memory is correct, the original label was not a decal, but a round sticker. It was applied between the forward nut on the valve cover and the front of the cover. But in contrast to the precision which marked the placement of decals on the side of the valve cover and on the oil filter, for example, this round sticker had a random position on its axis; the print on the sticker was never plumb or square to anything.

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Articles in the "Bugle" in the past suggest very strongly to use AC plug recommended by Buick in the manual.A "too hot" plug will blow a hole through the piston.Read past "Bugles". "Good ol'Joe" is usually on target.If it were my pet ,I would use AC 46X PERIOD !

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Articles in the "Bugle" in the past suggest very strongly to use AC plug recommended by Buick in the manual.A "too hot" plug will blow a hole through the piston.Read past "Bugles". "Good ol'Joe" is usually on target.If it were my pet ,I would use AC 46X PERIOD !

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Colder plugs transport heat from the electrodes to the head easier. Under conditions where the plug might over heat (hard, high speed driving) a colder plug is a good idea.<P>Hotter plugs transport less heat from the electrodes to the head. They are a good choice for engines that never get fully warmed up. (Short, local driving.) This will keep them from fouling as easily.<P>Look at the old plugs when you pull them for a tune up. If they are black or oily, a hotter plug may be in order. If they look burned, a cooler plug may be in order.

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I just ran into the same problem with my 56 V8. I emailed AC Delco and the response was the replacement is the R43. I put the R43's in last night and will probably fire it up later this week (rebuilding carberator too).

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Here's the answer I got from AC Delco:<BR>-------------<P>Thank you for contacting ACDelco.<P> In regards to your inquiry, the information you have is correct. The R44 has<BR> been discontinued, we<BR> show the R43 is the direct replacement for the R44.<P> Thank you for your interest in ACDelco.<BR> ACDelco Customer Assistance<P>-------------------<P>I think I'll use the AC 45 (hotter plug) or go with joe's suggestion (AC 46).<P>Thanks for all your input.

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1951 Buick Shop Manual--- PAGE 295,Section10-4 paragraph c, Spark Plugs Make AC,Model 46X. The 4 stands for 14 MM,The 6 is the heat range,the"X" is for the extended terminal.The extended terminal puts the plug connector a bit farther from the cylinder-head casting,Buick is the only car I have encountered so far that uses this extended plug.The circa WWII buicks used 48X,but about the time the 248 came with a slightly larger carburetor,they went to 46X.I could use 48X in my 41,but I like to open up carburetor #2,so I have 46X in it,to lessen the chance of blowing a piston.

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