astm D4683 vs astm 4741

[buster]

Viscosity at the shear rate and temperature of this test method is thought to be representative of the condition encountered in the bearings of automotive engines in severe service.

vs

Viscosity measured under the conditions of this test method is considered to be representative of that at the temperatures and shear rates but not the pressures in the journal bearings of internal combustion engines under operating conditions.

Is there any significant difference between these two methods?

 

[buster]

Anyone?

 

[Steve S]

The difference is 58 [4741-4683=58] I am not sure of the significance though.

 

[jpr]

Interesting question -

The ASTM D 4683 appears to be the older method (2004), and also is refered to as the TBS (tapered bearing simulator) method.

The ASTM D 4741 is newer (2006), and is also known as the TPV method (tapered plug viscometer). This method is also known as CEC-L-36-A-90 and is the test specified by the ACEA.

The results of both test are very similar, with the 4741 being signifcantly mor repeatable and slightly more reproducible. The 4683 values tend to be slightly higher (0.02 or so)

 

[jpr]

Incidentally, both methods (along with ASTM DS481) are acceptable for determing HTHS for the SAE J300 viscosity grade criteria.