Also, I have a quantity of old but clean and un-used 90 weight gear oil.
Wondering if mixing a couple of quarts of that with the regular engine oil would be a diagnostic tool in that a bad rod might run quieter with the thicker oil, or possibly even running such a mix if I chanced a 1500 mile trip with it ticking.
There is good oil pressure, no burnt smell to the oil, and the temp stays right at 80C.
Thanks again folks for all your help.
ed
Taken from another forum:
I have posted this chart to be used as a reference. It basically shows how to compare oil viscosity between different viscosity ratings. An example would be to show that an SAE 50wt ENGINE oil is close to the same viscosity of 90 weight GEAR oil at operating temps. It can also be used when comparing UOA's as some labs use Saybolt (aka: SUS) viscosity while some use Kinematic (aka: cSt) viscosity.
http://i304.photobucket.com/albums/nn169/White_Buffalo/oil%20analysis/viscosity_chart.jpg