I tapped the holes in mine and I am very glad I did, it is very easy, and has saved my bacon twice so far. I would not even consider building an engine without tapping the holes. When I first found out I had to drop the pan, I was absolutely livid. Now that I know the reasoning behind it, it kind of makes sense. But I don't have shims, so it would be even more stupid for me to NOT tap the holes. I don't really know where you would put shims, the main bores in the block are held to a plus or minus .0005" tolerance, as well as the crankshaft. The only thing I can figure is they made the bearings with a whole lot of eccentricity back when to facilitate the egg shaped hole you would end up with if you put shims under the main caps to to enable you to adust things. They seemed to like to make every thing so you had to adjust it back then. Either that or they hadn't quite figured the precision part of the precision insert bearings. Either way when I ordered bearings from Egge, anything after '47(?) doesn't come with shims. But that didn't stop the machinist who was butchering my engine from ordering a set of shims, which turned out to be 1(one) shim of about .013" thick for each bearing. Can't figure what type of adjustment could be done with those...I also vote no on the silicone. I don't use sealers at all on most things, usually anti seize. But the sheet metal on these engines tends to leak a lot if you don't. I used some sort of gasket shellac, permatex or something I don't recall exactly. Silicone has its place, but inside your engine isn't one of them.
Last edited by brokenhead; 11/22/2012 6:58 PM.
