I need some help with fouling plugs in my 46 Buick. I have done a compression test on each cylinder and got reading of 105psi to 109psi on each. According to the spec. sheet 112psi is right, which seems close. I am not burning any noticeable amount of oil. I changed the oil after 1800 miles and added nothing, I only do short trips with the occasional longer trip. I use this car for everyday driving.

I have been on a hunt, to find out what the right plugs are that will match the AC48 plug that was originally supplied.
Thanks Again for those how answered with help on my other post.
But AC plugs are not that easy to get here in Australia. I have been looking around for a good replacement and found a Champion J5 according to Green Spark Plug Co. on the net. Now Champion here no longer have this plug and have replaced it with a Champion J6C, which is now in the car. But as before it is fouling. No misfiring yet but I assume it will come soon.
Now can any other owners who have run hotter plugs on a everyday driver, reliably, help me find the hottest plug I can use, that will not melt on usual street running or on the highway, this is a stock engine. There seems to be no other explanation for the fouling there are no other signs of a problem. It does seem impossible to know where you are on heat ranges for plugs and interchangeable plugs, especially here with older plugs, as most auto stores do not go that far back, so anyone with some experience with this would really be appreciated.
Thanks Again for all your help.
Regards. Bea1946. :thumbsup:

Maybe you could find an old Mom and Pop operation who carries some old AC plugs. There was a C49 plug that ran a lttle hotter as it was commercial. If you are not doing high speed runs, and these plugs are ok.
There are two issues, one is the proper size, and a recent run has assigned this number to a much smaller plug.

I use Autolte # 86, they are an extended tip spark plug. I also set the gap to .025. If your spark plug wires are good, you should have no trouble at all.

I thank you for your help. As you mentioned the spark plug leads. The car came to me delivered with new ( as in modern silicon carbon leads fitted) not the copper high tension leads that it would have had. The resistance of the new leads was far to high. So I have remade the leads with some new copper high tension lead from my little auto shop yesterday and so far so good. I have not been on a good run yet, only around the block a couple of times, but the engine is far more responsive. Thanks Again. Regards.

It is my pleasure to help anyone, if I'm not sure of something. I will state that I'm not sure. Once again you are very welcome. How about a photo of the 46? Can you do that?

Thanks Again Anthony, I have a photo of my car at my web site. http://www.somethingwoody.com. There are other vintage car parts there that I make. I will also put it on here as well.
Regards.

Hi Tim.I see my brother had sent you some advice On spark plugs and wires.I have a 48 buick Roadmaster 49 years now.my brother Anthony has his two Dr.33 years my engine had low compression the rear clynders 80 and 90 the rest were 100.I used V-Power Racing plugs NGK R5670-5 Or stock No.2298.My car is a stock engine and runs beautiful :shifter::bana::waving:

If all else fails you can buy Spark Plug Non-Foulers at almost any auto parts store. I used to sell them when I worked at Autozone. What they are, are spacers than you screw your spark plug into, then you screw the spacer into the head. There is a small hole at the bottom of the spacer that allows the gas to get to the spark tip and to allow the flame to get out of the spacer. These work really well if you have a large oil foul problem. You have to match your spark plug seat to the same seat on the Non-Fouler. These have been around since the forties and they really work when nothing else will. Good Luck.