I’ve a fairly early Mk2, predating the advent of the rope seal and, therefore using a scroll to sort-of keep the oil in the rear of the engine. Now that the car is pretty well sorted otherwise, I’ve been trying to road it a bit more, and I’m finding more mess from rear non-seal oil leakage than I like. As for blow-by, this is operationally the best of several XK engines I own, and I seriously doubt that this engine has major wear. It starts instantly, blows no smoke in any circumstances, doesn’t seem to burn oil (sometimes hard to tell on low driven mileage with oil leakage), has great power, and is easy to tune - probably could idle it below 500rpms if I wanted. Running 20-50W Castrol with ZDDP additive. It hasn’t been very long since I had the breather screen off, and I haven’t rechecked it. I’m running some other engines with rope seals that I have rebuilt and I can’t say that they have no leakage, but they are better than this one - it’s my only XK with a scroll and the only one I did not personally rebuild.
I’ve read a lot of posts here about PCV systems although mostly pertaining to V12s, and I’m pretty familiar with it after struggling to get it right on my Morris truck with 1275 BMC engine - these will have serious leakage issues if you don’t.
Question - has anyone actually added vacuum to a Mk2 or other vintage XK crankcase through PCV, a vacuum pump or other means? I’d like to benefit from your experience. Before I take on the significant job of adding a rear seal or going through this engine, I’d like to try a simpler solution. If so, how and where to pull vacuum. I’m concerned about the wisdom of a T-fitting off the vacuum line to the brake booster. Maybe tap the manifold for another fitting? Thanks