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Old 10-28-2023, 03:18 AM   #4
69a
Senior Member
 
Join Date: Aug 2020
Posts: 326
Default Re: Oil after break-in

VR1 is recommended because it has a high Zinc content which is beneficial for flat tappet engines. There are some on here that say we don't need it on our engines because of the low valve spring pressure. I am no expert. but I am running VR! 20W50 in a rebuilt Flathead. My oil pressure is 80psi even after 20 miles at 180deg. I think 80 is way to high! So I'm thinking 10W40 or 15W40 may be better. If you are running an oil filter (any style) I don't think detergent level will matter.

Last edited by 69a; 10-28-2023 at 05:13 AM.
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