lets talk about oil

Now i have rebuilt my 340 Engine and the question is,, what oil do i use? oil with zink is propably good for my Engine (flat tap). How Little and how much? How about fosfor, cleaning additives. Mineral or syntetic? I saw syntetic oil with zink,,

I have always had good luck running diesel 15-40w. It has a higher zinc level, though apparently it is coming down too:( It is also detergent, so it keeps your engine cleaner.

I use shell rotella 15w30 in all of my older flat tappet engines, 1966 djb onan,1967 buick 340 skylark, 1973 l82 chevrolet corvette, 1986 305 silverado, and all of my wheel horse tractors with kohler engines from 1967 to 1970, briggs and stratton mowers 6 to20 hp with no problems. I have friends that have tried synthetic oils with good results the only complaint was oil leaks...

Bob

Using diesel oil was an early solution, but today we have oils made just for older engines. Diesels are lower RPM engines with soot that the oil has to deal with. Diesel oil has a lot more detergent in it for that reason. Here's the thing though, the Zinc (ZDDP) and calcium detergents in the oil are antogonistic. The Zinc wants to stick to engine parts, and the detergents want to remove it. Your best bet is to use an oil engineered from the get go for your older engine. IMO, you have two choices, Brad Penn Oil, or Joe Gibbs Driven Hot Rod oil. More expensive?, Yes, but for a new engine, worth the money.

http://www.jegs.com/p/Glockner-Oil/P...86175/10002/-1

https://www.summitracing.com/search/...ands-_-keyword

The BR-30 is what I would use for break in protection. Then use 10W/30 conventional or synthetic.