HI, i have snapped the dizzy retaining stud in the head of my 49 mercury. does anyone have a pic of the head off the block? Know how deep it is safe to drill to re tap before having to completely remove the head? thanks
Hi, Judderman! Welcome to the HAMB... I have a head off a '49 Merc, and just now measured the thickness of that flange. .550". There is a small mill counterbore underneath, so you don't have to worry about drilling into the block...IF you go with a positive stop of 1/2". (.500") Rather than just drilling it out: Soak the broken bolt stub with a GOOD penetrating oil, for 15 minutes or so. Take a flat-nosed punch, and hit the broken bold squarely on top...just a few taps, loosen it in the threads. Center punch the stub squarely, and using a 1/8" bit, drill the center down exactly 1/2" deep. Now, use a LEFT-HAND (reverse) drill bit, turning counter-clockwise. Start with 3/16", again down to no more than 1/2" deep. If the broken bolt didn't sieze up on the drill bit and unscrew itself, it will with the next size: 1/4". Use penetrating oil generously, it is your friend. That's a 5/16" USS bolt in there, so it should come out with the 1/4" reverse bit... Cheerio, from the Colonies!
judder_man, Not familiar with your problem but remembered this info on The Ford Barn. Maybe it will be of some help. Larry http://www.fordbarn.com/forum/showthread.php?t=280&highlight=Broken+studs
Hey mike if you get chance could you get me a pic of reverse side of head and the block area underneath the stud many thanks
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