In the old days, I would have just charged ahead on a wing and a prayer…
The power of corrosion is formidable… that sense of unity is no less than welding—it’s a law of nature.
With a clearance of about 0.00, I press it into the head cover and prepare to drill.
A drill press basically has no flat surface and the head is heavy, so there’s a risk of it bowing. Should I use the milling machine instead?
But then I decide to push ahead with the angle drill, which gives me more freedom.
Before that, I sharpen the drill and do the centering carefully, putting all my hopes into it…
Please don’t break… please don’t go at an angle…
The broken head wasn’t flat, so I was worried, but somehow I managed to drill right through center ★
The extractor didn’t work either, so I gradually enlarge the hole diameter along with the drilling jig.
The oil-cooled head cover bolt is M7 P1.00—a rare size. Of course, I keep taps, helicoil taps, and helicoils in stock.
I tapped it from the pilot hole diameter, but the thread edges aren’t standing up cleanly, so I decide to install a helicoil for safety.
Somehow, as you get older, helicoils go in perfectly on the first try? I guess it’s because I’m looking carefully as I install them…
Beautifully restored and complete. By the way, I’ve been wrestling with this for about two hours now…. Phew.
