The Ford Barn

Gezer · 06-19-2023, 03:00 PM

What is the best engine oil for a stock 51 EAB flathead and why?

J Franklin · 06-19-2023, 03:31 PM

I'd say the most expensive you can find in the right viscosity. And why? Because it has to be the best!

cadillac512 · 06-19-2023, 03:40 PM

Here's a recent thread. You're on your own!

Terry

https://www.fordbarn.com/forum/showthread.php?t=327442

38 coupe · 06-19-2023, 04:44 PM

The worst new motor oil you can by in a reasonable viscosity (NOT 0W-anything) will be way better than the best motor oil available when our flatheads were new. It is hard to go wrong wtih new oil, and everyone has their own opinion. I personally run 15W-40 diesel motor of some type in all my old cars. If you use synthetic be prepared for oil leaks.

Jacques1960 · 06-19-2023, 05:17 PM

Shell Rotella 15w-40 with a splash of MMO

Flathead Fever · 06-19-2023, 06:56 PM

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Same answer for all my vintage flat tappet engines. Delo 15W-40 diesel oil with the anti-wear additives or the equivalent Shell Rotella diesel oil. Walmart usually has it cheapest. Those two will be the easiest oils to find. Probably any of the oils recommended for diesels of flat tappet gas engines. The weight of the oil will depend on what your engine setup likes to get a decent pressure. The amount of wear in the bearings or the initial setup clearances, stock oil pump or high-volume oil pump will all make a difference in the pressure. 15W-30, 15-40W, straight 30W. They will all work. Its a good idea on an unknown engine with nasty oil to pull the pan and clean the oil pump pickup screen. They can get plugged up really bad.

06-19-2023, 03:00 PM	#1
Gezer Member Join Date: Apr 2016 Posts: 98	motor oil What is the best engine oil for a stock 51 EAB flathead and why?

06-19-2023, 03:31 PM	#2
J Franklin Senior Member Join Date: May 2010 Location: Oregon Posts: 5,998	Re: motor oil I'd say the most expensive you can find in the right viscosity. And why? Because it has to be the best! Last edited by J Franklin; 06-19-2023 at 03:37 PM.

06-19-2023, 03:40 PM	#3
cadillac512 Senior Member Join Date: Apr 2019 Location: Kansas Posts: 971	Re: motor oil Here's a recent thread. You're on your own! Terry https://www.fordbarn.com/forum/showthread.php?t=327442 __________________ "It don't take but country smarts to solve the problem" (Smokey Yunick) '41 Merc Town Sedan / 260" 8CM engine '66 Fairlane four door / "warmed up" 302

06-19-2023, 04:44 PM	#4
38 coupe Senior Member Join Date: May 2010 Location: South Texas Posts: 1,675	Re: motor oil The worst new motor oil you can by in a reasonable viscosity (NOT 0W-anything) will be way better than the best motor oil available when our flatheads were new. It is hard to go wrong wtih new oil, and everyone has their own opinion. I personally run 15W-40 diesel motor of some type in all my old cars. If you use synthetic be prepared for oil leaks.

06-19-2023, 05:17 PM	#5
Jacques1960 Senior Member Join Date: Sep 2020 Location: Mount Desert, Maine Posts: 504	Re: motor oil Shell Rotella 15w-40 with a splash of MMO __________________ No job’s done ‘til it’s all done

06-19-2023, 06:56 PM	#6
Flathead Fever Senior Member Join Date: May 2010 Location: Yucaipa, CA Posts: 1,101	Re: motor oil Sponsored Links (Register now to hide all advertisements) Same answer for all my vintage flat tappet engines. Delo 15W-40 diesel oil with the anti-wear additives or the equivalent Shell Rotella diesel oil. Walmart usually has it cheapest. Those two will be the easiest oils to find. Probably any of the oils recommended for diesels of flat tappet gas engines. The weight of the oil will depend on what your engine setup likes to get a decent pressure. The amount of wear in the bearings or the initial setup clearances, stock oil pump or high-volume oil pump will all make a difference in the pressure. 15W-30, 15-40W, straight 30W. They will all work. Its a good idea on an unknown engine with nasty oil to pull the pan and clean the oil pump pickup screen. They can get plugged up really bad.