Originally Posted By: Trav
Originally Posted By: Clevy
Originally Posted By: kschachn
Originally Posted By: aquariuscsm
20 wts are probably perfect for a 4-banger. Anything thicker would probably slow them down. A muscle car engine would probably destroy itself on a 20 wt.
Why is that exactly. If the engine has adequate oil pressure and volume what exactly is it missing causing a larger motor to destroy itself.
Crank flex its that simple. The more cylinders and less main bearings the more flex can occur.
For low viscosity oils to protect properly the crank must remain totally stable in its main bearing bores which use lower clearance bearings.
This is a serious consideration for anyone considering running lighter oils in older engines or engines not back spec'd for low viscosity oil.
http://www.enginebuildermag.com/Article/...and_racing.aspx
Good answer. K. Thank Trav. I'm going to read the link.
I wasn't being facetious when I asked. I am glad that you could give a sensible reason why.
But is this a real issue if only going one grade thinner? I know going thicker may affect fuel economy but is going one grade thinner a possible serious issue,and asking for catastrophe?
Thanks
Edit
Awesome link. Saved that to home screen.
Thanks Trav