Why 50 weight oil in a marine engine? The oil is thick and hard to pump, and takes longer to get back to the pan, why not 15/40? My motor desperately needs oil tstats (which it will get) but running that thick ass 20/50 knife edged my distributor gear. I would think there is a big parasitic loss just pumping it and there would be some substantial gains running 15/40. What advantage does the 50 weight have?

VR1 straight 40w here.

Film thickness. More cushion for the pushin.

Straight 50 ? 20/50 ? 15w/50 ?

You sure the oil weight did that to the gear ? If so, what oil temps ? What material is the gear ?

BTW: You wouldn't happen to have an MSD dist with both o-rings installed on the shaft housing would you ?

All straight weight oils have no polymer to shear.

Ken

20/50. Bronze gear, very rarely made it over 130*. Judging by priming the pump with a 1/2" drill...it is definitely causing the knife edge.

Hmmm...I do not know

I ran 50 weight VR1 in my engine last year. When I pulled the distributor this spring, mine was also prematurely wearing. I'm switching back to 15-40.

been running 20/50 for YEARS never had any issues with gear, might want to check Dist depth, remove lower O ring also....

With a bronze gear in a endurance application I'd also consider doing the Crane Cam tech tip of putting small groove in bottom of shaft housing to spray oil at the gear.

I'll try to find it in a bit so you can see. I Will also explain why to get rid of MSD's bottom o-ring if present.