Break in oil has maybe 3 hours on it but is a couple years old. New VR1 and cheap Fram filter for the next couple years. Higher than stock valve spring rate pointed me toward the 20W50. Oil was actually darker than I was expecting, haven't cut open the Hastings filter for a look see yet.
Out with the HPL and in with the Valvoline
- Thread starter sloinker
- Start date
The spring rate has little correlation with viscosity. The viscosity/grade is determined by the rod and main bearing clearance as they're the only parts of an engine that operate solely in hydrodynamic lubrication, where there's a MOFT threshold.
.0016-.0021" = 20 grade
.0022-.0028" = 30 grade
.0029-.0034" = 40 grade
.0035" and up = 50 grade
Using a higher viscosity than necessary won't necessarily hurt. You may get higher bearing temp from the increased hydrodynamic friction, will likely be a little harder to crank over in cool weather, but that's about it. I just don't want you feel you have to use a 20W-50 oil, that you can run a lower viscosity if preferred and clearance allows it.
VR1 is a solid choice. Nice classic mopar.
.0016-.0021" = 20 grade
.0022-.0028" = 30 grade
.0029-.0034" = 40 grade
.0035" and up = 50 grade
Using a higher viscosity than necessary won't necessarily hurt. You may get higher bearing temp from the increased hydrodynamic friction, will likely be a little harder to crank over in cool weather, but that's about it. I just don't want you feel you have to use a 20W-50 oil, that you can run a lower viscosity if preferred and clearance allows it.
VR1 is a solid choice. Nice classic mopar.
Car is garaged 100% of the time. Driven hardly at all a few times a year to keep everything in shape and ready along with the battery charged. the VR1 is cheaper than HPL and meets my needs. Like you I felt the 20W50 wouldn't hurt anything.
In 1971 I bought a 70 Challenger with the 340 engine with a warmer that stock cam, intake, headers and carb and a 4 speed and the normal hot rod stuff of the day and used to drive from Millbrae Safeway Store where I worked the 3 to midnight shift. I would every week go to my freinds house in Clear lake oaks to water ski etc for the week ends which were Sunday and Monday for me and used to drive 80 mph on the freeway and wide open throttle as possible on the Silverado trail to Clear Lake Oaks ,,, 6400 rpm on the tach for miles and miles kinda like Vanishing point the movie ,,,any way I ran 20W-50 in it because that is what the cool people ran in their Hot rods. The engine ran good with 134,000 miles on it when I sold it to buy a pick up with a camper. I remember some things well and others no so much.
I had a 1970 'cuda with a 340 automatic. That engine really ran well at higher RPM's. The 440 in my current Mopar has grunt all the way from idle and is fun in a different way.
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