The Ford Barn - View Single Post - What should I use for oil in 40 Ford flathead?

Ol' Ron · 06-30-2013, 09:29 AM

What some people don't consider is the fact that the engineers that design these things have a better idea of what viscosity oil to use. The Flathead was designed to run 10 in the winter and 30 in the summer. Bearings need lubrication, But they also need cooling. The thinner oil removes the heat in the bearing. Heaver oil jut lubricates the pressure relief valve creating more heat. Modern engines use oils as low as 0/10. Using a hi viscosity oil just to see the gauge show 50lbs just means the relief valve is working overtime and the bearings are getting hotter.
IMHO

06-30-2013, 09:29 AM	#20
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,860	Re: What should I use for oil in 40 Ford flathead? What some people don't consider is the fact that the engineers that design these things have a better idea of what viscosity oil to use. The Flathead was designed to run 10 in the winter and 30 in the summer. Bearings need lubrication, But they also need cooling. The thinner oil removes the heat in the bearing. Heaver oil jut lubricates the pressure relief valve creating more heat. Modern engines use oils as low as 0/10. Using a hi viscosity oil just to see the gauge show 50lbs just means the relief valve is working overtime and the bearings are getting hotter. IMHO