First, my 1970 144 with original B20 (151K miles on it) runs fine, no oil burning, but it always idled a little rough (even after a complete tune-up) and cranked over slowly. If I advance the timing to where it's supposed to be (a volvo mechanic double-checked it for me), it sometimes cranks really slow. I say sometimes because I'll turn the key and it will crank slow (almost stop for a second or so), then I'll turn the ignition off and then back on again and it will sometimes crank freely after that. There's nothing wrong with the battery. If I retrard the timing a bit it always cranks freely. I suspect cam wear (which would also explain the slightly rough idle, no?). I don't know the history of this motor, but it sure looks like it's never been apart (leaks oil in a few spots indicate gaskets were never replaced), but I think it's amazing that it burns absolutely no oil at 151K! I've heard that the cams on these engines can go bad at around 100K. Do you think I should replace it? Is a engine "refresh" of a new cam and lifters recommended on a motor with this sort of mileage? Does the head need to be done also?

Also, I was checking my oil over the weekend and when I pulled the oil filler cap off I noticed some light brown sludge under the cap. It almost looks like chocolate milk and has a greasy consistancy to it. I wiped it off the underside of the cap, but now I'm wondering what the heck it's from. I never noticed it before. The only thing I can think of is that the last time I changed the oil I used a oil (quaker state I believe it was) that was formulated for older engines to assist with oil buring/leaking. I'm worried that maybe I'm getting water in the oil though. I only drive this car to the train station every day (which is 2 miles from my house) so maybe that's part of it.