I have used 5W30 in mine from day one and when i rebuilt mine in the 80's I even threw away my oil deflectors in the lifter valley to allow more oil up there. I used 15W40 once and if I had the car sitting in storage for a long time the valves were more prone to sticking so I went back to 5W30 for the main reason, these valves are "mist" lubricated, not lubricated by oil flying off rockers that have pressure fed oil to them. I used full synthetic as well and guess what? My weepy dipstick cork gasket and rope seals leaked virtually next to nothing so the extra leaks being caused by synthetic is false unless your ropes are just plain worn out. As for the zinc, there are still many flat tappet engines out there so I don't believe this theory either. As for theories, theoretically the Bumble Bee is not supposed to be able to fly because her wings are too small, but they fly very well

If anything our oils are much better quality than they used to be back in the day of straight grades only before the multi-grades. I have always used good quality oils and not the cheaper brands for one reason, do the math per mile of what a buck or two more costs you over the full length of the time the oil is in the crankcase. My cam after all of these years is surviving quite fine and my oil pressure is still 75+ PSI on the highway. As for the camshaft, the only mistake I made was putting adjustable tappets in instead of using the original. Putting new tappets on a good used cam doesn't harm the cam, but the new tappets seat or wear into the good used cam and a number of times i had to pull the *#!*&% intake, generator, fan, belts etc. etc. and reset these lifters.


I have been a mechanic for 35 years and I was starting out

back then and used them. Since then I have rebuilt 5 of these engines and once these valves are properly set they stay that way, that is of course KEEPING all of the tappets where they came from. I work on many small engines as well that have their valves set the same way and this doesn't worry me and I find them easy to deal with. I also ignore the valve chart in the manual saying on top dead center you can set this valve and the intake on this cylinder, and the exhaust on another. A great recipe for ending up with a few noisy gremlins when the job is done.