928Belgium

Hello all, after hearing some noise coming from the fan I noticed some play on the fan.
Hoping to resolve this with rebuilding one of the fans I have laying around.

I noticed some difference in all the parts so here are some questions for the experts:
- there are 2 different types of supports, one without reinforcement ribs (2x '79) and one with ('80 and '84) => did Porsche make them stronger because they are too weak without them?
- I also have 2 types of fans: aluminium and plastic with metal centre => untill what year did they used the aluminium version? Did they change to the plastic version because they are cheaper to produce? (I feel that the aluminium ones are much lighter in weight) and I noticed that the positioning of the blades is assymetrical, what is the reason for this?
-The shaft has 2 bearings, for one I ordered an alternative from SKF at almost a third of the price of the Porsche bearing, but I didn't found an alternative for the bearing with the wide inner ring => Someone who know an alternative for this?

Thanks in advance for you thoughts and advice!

928Belgium

jpitman2

I had no trouble finding cheap stock bearings for my 83S fan bracket - common size bearings..The asymmetric blades will be to reduce resonances at some speeds. My car is a C16 (UK spec) and came with the alloy fan, and was then exported to Saudi, where that fan would not have coped with summer temps, especially if the silicone got out, which it always does. I did try refilling the viscous with Toyota silicone, but it bled out fairly quickly. Since I had a LR Discovery there, and was familiar with its viscous coupling and fan (large dia and 11 blades), I modified a 928 fan shaft to fit the Disco unit. The viscous on the Disco is attached to the water pump shaft with a LH threaded fitting. I pulled the 928 shaft out of a dead viscous coupling, turned the end down a tad, removed the LH threaed part from a Disco water pump and pressed it onto the 928 shaft , and now had a bigger fan, witth a much cheaper to replace viscous. Seemed to work better than the original, still have the whole assembly somewhere.. Would have been better to go straight to a full electric fan solution, which I have eventually done - pair of SPAL 11" units in a shroud.
jp 83 Euro S AT 57k

76FJ55

I recently replaced the bearings on the fan carrier of my 85. A 3rd part number after the ones you listed before, which has the bracing like the 84, but incorporates threaded bosses for mounting the throttle linkage. I just used generic bearings. If I remember correctly the forward bearing was the one with the wide inner race. I just used a standard bearing to replace this one as I do not believe the wide inner race performs any specific purpose. the fan shaft is located off the rear bearing to ensure the pulley is in plane with the belt run.