that is funny, I wouldn't even consider anything heavier than 10w-30. I ran 5w-20 in my truck engine for about 10 years simply because that is what I used in my new cars, and had around the garage. We got new centrifuges at work, they have approximately 10" OD roller bearings on a bowl that weighs 8400 pounds empty, and spins 2800 RPM. It has this weird oiling system that injects 2 drops of oil every 5 minutes, and uses ISO 32 oil which is very thin. I guess the point is, everything I THOUGHT I knew about lubrication wasn't necessarily true. From a purely lubricating stand point very little oil is necessary, however another, if not the most important job of oil is the removal of heat. Which is one of the reasons race engines use such large clearances. But enough of that. Engine oil is what you should use in your engine, as you can tell from the posts nearly everyone has their opinions, and yet nearly all of the engines run just fine, despite all this. There have been people that swear by 50 weight racing oil. And as you see several people insist on straight weight. Personally I see no reason to even manufacture a straight weight engine oil any more. Even caterpillar has conceded and specifies multi-grade oils in their engines now. But nonetheless the final decision is on you. They all work. The last thing is regarding synthetic, no cam manufacturer (that I have found) recommends synthetic for flat tappet break-in, according to the fella at crane cams it is because it doesn't provide enough "TRACTION" to spin the lifters adequately to get a proper "bedding in" of the lifter/cam lobe. However once it has been seated, synthetic is an unquestionably better lubricant, and if you have no/very little leaks would/could be a good choice. It is more expensive, but you double the drain intervals. Note that all this is my opinion.
Last edited by brokenhead; 07/02/2016 3:02 PM.
