On Mon, 23 Oct 1995, John M. Trindle wrote:
> If this message doesn't make sense give it 4 hours sleep and a cup of coffee.
>
Oh no, a .com that doesn't get much more sleep than I do......Please tell
me that I'm going to get more sleep after I graduate......PLEASE
The viscosity question is a good one......
Here's what I know (think I know, my fluid power book is at my apartment).
SAE 20w50 means that the oil acts like a 50 weight at 0 deg C, and a 20
weight at 100 deg C....So the viscosity decreases (easier to flow at high
temps) with temp....
I beleive the reccommended weight is straight 20. This would be an oil
that act like 20 weight at 0 deg C AND 100 deg C. Lets assume
that the temp of the carb piston chambers dosn't get too hot (they run
cool with all of that intake air running through them) SO, they might
reach 110 deg F (43 deg C).....while the engine is at operating temp.
If the change of the viscosity of the oil is linear, then at 43 deg C,
the 20w50 oil acts like a 37 weight.....IF I'm right (more like, if I'm
not wrong), then the oil IS TOO viscous (hard to flow) at the assumed 110
def F. So YES, it would take the carb pistons longer to go down, causing
your engine to take longer for the revs to go down.
Eric "user of the SWAG system"
Eric L. Van Iderstine - ME senior - Mississippi State University
Design Coordinator - MSU Formula SAE......Powered by Honda......
elv1@Ra.MsState.Edu http://www2.msstate.edu/~elv1
74 MGB & 85 Buick (until I finish the MG)
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