Updated: Jun 11, 2021
theres a lot of opinion surrounding what oil should be used on vintage engines. we insist that vintage flat tappet cam, pushrod engines require a propper amount of zinc in every oil change. not JUST during engine break in. we use valvoline VR1 10w30 racing oil on all these engines, including as a break in oil. the reality is you can use any conventional gasoline engine oil you like with a zinc (zddp/phosphorous) additive. dont use an additive with racing oils/ classic car oils that already have zinc in them, as too much zinc is actually very corrosive. the zinc is an anti scuffing agent that provides a high pressure withstanding protective film around high stress points such as cam lobes, fuel pump cam eccentric, pushrod tips, rocker tips and chain/gear wear. running really heavy 50 weight oils is not necessary, and does more harm than good. heavy oil does not mean better protection. if your worn out engine burns a lot of oil, 20w50 may be a better option for you, however. running a heavy oil during engine break in can actually keep the rings from seating. also a big contributor to lifter noise. the oil galleries on these engines are also very tiny. i highly recommend that people dont use synthetics. they can also keep the rings from seating during break in. the biggest concern is leaks. vintage engines have very crudely designed gasket surfaces and gasket designs that synthetic oil isnt forgiving of. go put sythetic oil in an old harley and you'll see what i mean. i highly encourage people to not use diesel oils. diesel oil is for diesels. they arnt marketed for use in gasoline engines for a reason. excessive amount of added cleaning detergents/ solvents designed to deal with the crank case soot on a diesel, which can have an adverse effect on ring life over time and create crank case contamination via breaking loose deposits.. (also take note that diesel oils have little to no zinc in them anymore due to rising emission standards. this started over a decade ago.) and entirely wrong set of additives for the wrong application. is your engine going to blow up over night from diesel oil use? of course not! that being said, its 2021. theres no excuse for using the wrong product to protect your very expensive investment. people claim diesel oil is cheaper, and it is. but the average classic car only gets driven 3k miles a year, so chances are, you're only changing your oil once or twice a year. you can afford to spend a few more dollars. oil changes are the cheapest aspect in owning an old car. as for filters, stay away from fram! their filters are litterally a wad of crumbled up cheap cardboard. we've seen 15 PSI drop in oil pressure with a fram filter!. pretty much everything else available is the same filter, either relabled in a different box... or a couple more folded pleats in the element. fresh engines, i change the oil right after cam break in and a couple test drives. again at the 500 mile mark, and then 3-5k miles for the rest of its life. ideally its best to stay with the same brand of oil for the life of the engine. obviously, thats not possible if you aquire a 70 year old car thats new to you.. also, NEVER EVER put marvel mystery oil in any vintage engine EVER. marvel mystery oil is just mineral oil and solvent. its essentially the same as dumping sand in your engine. the entire inside of any unrestored vintage engine is caked full of grit which is a combonation of crappy vintage oil deposits, road draft contamination, and (mostly) lead contamination. solvents break all that loose, so it then gets thrown off the crank and up into cylinder walls and everything else, on its way down to the pan. the oil pan on your unrestored engine is also caked with an inch of that same contamination, which the solvents will delute and feed right thru the oil pump and plug the pickup. never try to clean any engine part, with it installed on the engine.