I've been fighting an oil leak on the MG for about a month now, and I'd pretty well tracked it to the front tappet galley cover. These covers are notoriously problematic on this engine-especially the front one that also serves as the crankcase breather.
A friend of mine makes and sells a one piece cover for this area. It's a beautiful piece of 1/2" aluminum.
The plate doesn't come with the crankcase breather already fitted, so "you can just drill and tap it." That sounds easy enough. The fitting included is 3/16 NPT.
I took it to work yesterday, but couldn't find a 3/16 NPT tap. I called over to the university machine shop, and the machinist said he had 1/4" and 1/2" but not 3/16. A tap was around $30 from the usual sources, so he suggested that I find a 1/4" fitting.
I visited the hardware store(best hardware store in town) and unfortunately all their 90º fittings were plastic-that won't work here. They did, however, have a 3/16" NPT tap for $12-so I went hope with that.
I HATE pipe threads as a general rule. Unlike a normal straight cut thread, the tapered pipe tap enlarges the hole in addition to just cutting the threads in it. I did a practice piece of 1/4" thick aluminum, and was throwing all my weight on a 12" crescent wrench to get it to go a half turn at a time(before backing off to blow it out). I'll also add that I was VERY hesitant about using a wrench on a tap, but this is a big enough tap that I didn't feel like I was in danger.
In any case, I called the machinist again and he said that the SAE 30 motor oil I was using as a lubricant wasn't a great choice. For that he advised a "proper" tapping fluid, and I trekked over again to get a little bit from him. It's probably about an SAE 20 weight oil with sulfur-based EP additives. In any case, it made the job is marginally easier. With much sweating and grunting, I managed to get the hole tapped.
Then, I came home and went to work fitting it on the car. The beauty of working on this side of an MG engine is that you pretty much only need a 1/2" combination wrench and 1/2" socket(plus a small screwdriver do undo hose clamps)
So, after an hour or so of work, I have this
I got the exhaust manifold rehung and the intake back on. I also needed to swap around the carb bodies and got that done. Unfortunately, I'm stuck as I have a nut hung on a stud that's trapped in the old carb body. I'll either get it apart tomorrow or pull a stud off a junk exhaust manifold.