Fan Clutch "CV" Ink stamp ?????

[CamarosRus]

Russ Guajardo has told me .............

"The differences in the fan clutches can be either external in fin configuration, models of cars assigned to, or different production runs by eaton. I was speaking only to the internals on these in my first response, the internals are exactly identical"

Can anybody explain why and or confirm if ALL the 7" Fan Clutches in 1970 were stamped
CV as Ive seen on the Z28........and CZ on Big Block......WHY if its the same internals and same external ............

And how is the date coding broken down on the EATON Fan Clutch

[jl8z28]

The shaft where it bolts up on the big block is shorter I think that's the only difference

[60sStuff]

I’m sure many Chevrolet people know how to decipher the coding on these fan clutches.

Just an example below of my early build 1965 GTO Survivor.
This is when I first removed my fan from this car before cleaning.
All early GTO fan clutches have a blue paint mark on them and I’m assuming that was test / pass marking.

[daveg]

After doing a bunch of homework I now see why the folks that know are silent on this.

Will pay more attention in the future.

[BCreekDave]

Originally Posted by CamarosRus

Russ Guajardo has told me .............

"The differences in the fan clutches can be either external in fin configuration, models of cars assigned to, or different production runs by eaton. I was speaking only to the internals on these in my first response, the internals are exactly identical"

Can anybody explain why and or confirm if ALL the 7" Fan Clutches in 1970 were stamped
CV as Ive seen on the Z28........and CZ on Big Block......WHY if its the same internals and same external ............

And how is the date coding broken down on the EATON Fan Clutch

Could be something as simple as the thermostatic coil that regulates the clutching action due to temperature. Perhaps slightly different cut-in/cut-out temperature. Also could be the viscosity of the fluid may be different. This would also change the "lock-up" characteristics. Kind of like how a transmission torque converter works.

[CamarosRus]

Originally Posted by BCreekDave

Could be something as simple as the thermostatic coil that regulates the clutching action due to temperature. Perhaps slightly different cut-in/cut-out temperature. .

The O.D. of the spring on the below AK Fan Clutch is 1.025 Inch

The O.D. of the unmarked Fan Clutch (believed to be my Original CV 1970
Z28 CTB engine) Spring is 1.075

Could members having a known/stamped CV Clutch please measure (with a accurate
caliper) and report back as to the O.D. (measured at 3 & 9 Oclock with "STORE FACE DOWN"
at the top)

[KevinW]

I saw this post and pulled this Delco CH 4939899 from it resting place (25+ years on a shelf). It's a factory 1969 Camaro small block with A/C or K02 extra cooling option. I figured I would join the fun and post the pics here Still firm to turn, part number 4939899 dated 305 of 68. What are these worth BTW?