I need to get some bolts that will thread into the plug holes in a flathead V8. 9/16-18 doesn't fit, maybe 9/16-24? Machinery's Handbook lists that size, but Fastenal doesn't show it.
Really, I didn't think Ford was using metric back that far! Are all 14mm threads the same, or is there fine, coarse, etc? The guy on the phone from Bolt Depot mentioned a special spark plug thread, but had no details.
Made a tool for pulling stuck heads. http://www.jalopyjournal.com/forum/showthread.php?p=5631554&posted=1#post5631554
I've also seen someone take old plugs and break out the porcelain then weld eyelets out of large washers for lifting the head off.
why you pulling the heads off you gonna sandblast them and hang em up somewhere. But I am glad you finally decided to run a motor that will last (FORD) hEHEHE
Are you sure on this? All I find are 2.0 mm and 1.5 mm pitch bolts. Is this some weird size I won't find bolts for?
Spark plug threads are not normal bolt sizes. Put in broken out spark plug bases and tap them or install bolts through them. Spark plugs are the only things that will match those threads, and I think most earlier plug threads are non-standard except perhaps the very early plugs made on pipe sizes... Questions need detail...they made flatheads for several years, you know, with three completely different plug sizes.
I follow you Bruce. These are 8BA or 59AB heads. I found dies with that thread, I could make up something, I just wanted a quick solution.
Plug threads are 14 mm x 1.25 pitch. This is a non-standard pitch, deliberately chosen by the manufacturers on a world-wide basis. As suggested, use old plug bases and weld an eye bolt or whatever you want in them. The threads won't pull out - plenty of strength for what you want. We've pulled engines using screw in eye bolts in the plug holes. Brian
If you plan to trash the heads anyway you could always tap them to the first US size that will clean up. 5/8-18 comes to mind. I think I would try removing the porcelain from a couple of plugs. cutting some bolts on the head end to fit well into the empty shell and weld or braze them together. Or go to a machine shop the can cut metric threads and have your bolt threaded by a single point. If you use a spark plug please don't just bash the porcelain out. Cut the crimp at the end of the shell and push the porcelain out in one nice clean, easy move.
If you look at a spark plug it has a steel shell and a porcelain insulator with the electrode in it. You want to remove the porcelain and keep the steel shell with it's threads. The common way to do this is get a hammer and punch and beat on it until you have broken the porcelain enough to get it out. Good if you are a cave man. Look at the plug at the top of the steel shell just above the hex and you can see where they crimped it over onto the insulate to seal it during manufacture. If you have a lathe use a part off tool to cut this crimp or spin the plug in a drill press and use a cut off wheel to remove the crimp. Now remove the ground electrode and using a punch and light blows from a small hammer you can push the insulator out in one clean piece. If you choose to bash it out you end up with broken pieces of porcelain all over and some still in the steel shell. Plus it's the hard way. Most don't believe that. Don't forget we descended from stone age man.
I robbed that photo from another thread; I was trying to avoid doing that, but it looks like I will. Should be easy after seeing the photo, and your explaination.
Yeah, I'm sure. The 1.25mm pitch is not a "standard" pitch for a 14mm bolt. The 2.0 is the equivalent of a "coarse" series pitch and the 1.5 is the "fine" pitch. You're not likely to find a 14M X 1.25 bolt, but you should be able to buy 14M X1.25 taps and dies at many sources like Enco. Bob
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