There has been some questions from the Engine Builders that they want to run a 50W oil. The “W” winter rate doesn’t really tell whether you can use a specific oil with hydraulic roller lifters as I have learned from both John Callies and Lake Speed Jr. What does matter is the centistoke number.

Driven has supplied this chart on flow ratings on the Driven FR50 and other popular 50W oils:

Ambient Temperature Oil Flow Rates
Oil Driven FR50 VR1 Brad Penn
SAE 5W-50 20W-50 20W-50
60F 328 cSt 786 cSt 627 cSt
75F 213 cSt 451 cSt 373 cSt
90F 144 cSt 275 cSt 235 cSt

High Temp Flow (for reference)
275F 9 cSt 9 cSt 9 cSt
300F 7 cSt 7 cSt 7 cSt

I have talked with John Callies at Morel about the Data above and he said the FR50 will work with the Morel lifters. For those that want to run a heavier oil you can run this with your Morel lifters.

 

What sort of centistoke numbers are out of range to work with Morels?

 

Isn't that why we have API and GL ratings? Because the viscosity numbers are so non standard among oil vendors?

 

Nothing above 150 at 90 degrees.

 

Interesting, so Brad Penn and VR1 are out. Is this across the board on all hydraulic Morel lifters? I'm under the impression that some of the Morel hydraulic lifters have tighter clearances than others.

 

I have had good success with Castrol's Edge 5w-50.

As rated by the OEM: http://catalog.parentpetroleum.com/i...ol-edge/55248?

The actual 100*C cSt numbers are here: https://www.bobistheoilguy.com/forum...t&Number=28865

For the non-metric crowd:
40*C is 104*F
100*C is 212*F

 

Thank you for the info.

 

Just to make sure i understand.. Royal purple 10w40 would fall within the spec mentioned for morel 5315's and is safe to use? From what i am seeing 20w50 appears to be over the spec and would not be safe to use? Just trying to make sure i understand the numbers since i run the 5315's. Thanks guys! Cool info to know!

 

Correct on the 10W40 Can use.
Correct on the 20W50 Can't use.

 

Awesome thanks!