John, I wouldn't run anything heavier than 10-40. 10-30 should be fine. You don't want to run a "straight weight" as it's a bit thick at start up. You could run 20-50 (I'm assuming that's what you meant by 20-40 -- no such weight!) because of the mileage, but if you do change the oil to 10-30 or 10-40 for cold weather (below 40 or so) driving. If you park it in a garage through the winter you should be fine leaving 20-50 in all year round. Smoking at start-up that quits shortly after is a classic sign of bad/worn valve stem seals. In your case it's normal, they harden and fall apart with age. The seals can be changed by a competent shop without removing the heads, or if you've plenty time it's not hard to do yourself. You don't need compressed air, though that's what a shop will use. I use a piece of cord small enough to fit in the spark plug hole. Run the piston down. insert about 3' of cord, then run the piston up to compress the cord against the valves, one cylinder at a time. Safer than air, but takes a bit longer. ------------- Date: Tue, 12 Aug 2008 00:30:24 EDT From: JohnBherna@xxxxxxx I have a 1967 Rebel with 122K miles. Runs fine, smokes very little at first start but not after that. What grade of oil should I use, 30 weight, 40 weight, 10-30, 20-40? -- Frank Swygert Publisher, "American Motors Cars" Magazine (AMC) For all AMC enthusiasts http://farna.home.att.net/AMC.html (free download available!) _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list