Alright guys, seeing if there's any oil guru's out there. I run 2.2 cavaliers on a dirt oval, have 2 identical cars front bumper to rear, inside and out. Last year we ran 20-50 conventional oil in a wore out motor. This winter I freshened both motors, rings, bearings, valve springs, etc. I went back with the same oil, only synthetic. Since then we have lost both motors. Are the motors to tight with new bearings, factory replacement, for 20-50? Do y'all think just going back to 5-30 will stop these motors from spinning bearings? And should I stick to conventional oil or will synthetic be okay? By the way the main journals, rods, and crank are all within spec. Any input would be appreciated.
A lot of use have ran 10W40.
I do not think you should spin bearings with 20w50 though.
I know a few dirt track guys have ran that thick. Most of the dirt track guys are on 2.4L twin cam motors though...