Fan Housing/Bell Housing
#17
This is not the first time something like this has been posted on the this forum or the 964 forum. I can't find that older thread for some reason, but it was really similar to yours, no warning signs (i.e. visible cracks), just a sudden, catastrophic, failure that caused other damage to the car. I think the other guy lost an A/C line from the flying debris.
#18
Black = corrosion.....holy cow that looks bad!
It appears as though the belts are still on the pulleys. The one belt has flipped either from oil or tension from the blade being jammed. If you have ever media blasted the fan blade to powder coat you would see that the factory paint is very thick and looks like it is pealing when it comes off. The fan blades are solid material and won't delaminate....
Pictures from my car below show the delam/cracking on the ends of the blades, unfortunately not the best pics:
Chipped paint and jagged crack on end of blade and chipped blade tip.
On the bottom of this blade, there is a 1/2"+ split forming (what I'd call delamination). You can see the split/opening in the end of the blade where there is a darker center section. The top side of the blade shows the deformation pretty well.
One of the threads talking about this:
https://rennlist.com/forums/993-foru...djustment.html
#19
Initially I was thinking black fan belt rub marks as you were, but impossible to tell from pics.
If that is corrosion, it started some time ago and periodic inspections should have picked it up, provided the parts/engine bay are kept clean. There are advantages to that.
I might guess poor handling of the fan assembly at some point, either while off the car or in the car....sort of like not knowing how to install bearings using correct installation procedures. Those tend to fail much sooner.
Out of curiosity, what is the ratio of the engine pulley to the fan pulley. I'd like to calculate the RPM at which these fans spin at.
If that is corrosion, it started some time ago and periodic inspections should have picked it up, provided the parts/engine bay are kept clean. There are advantages to that.
I might guess poor handling of the fan assembly at some point, either while off the car or in the car....sort of like not knowing how to install bearings using correct installation procedures. Those tend to fail much sooner.
Out of curiosity, what is the ratio of the engine pulley to the fan pulley. I'd like to calculate the RPM at which these fans spin at.
#20
If that is corrosion, it started some time ago and periodic inspections should have picked it up, provided the parts/engine bay are kept clean. There are advantages to that.
I might guess poor handling of the fan assembly at some point, either while off the car or in the car....sort of like not knowing how to install bearings using correct installation procedures. Those tend to fail much sooner.
I might guess poor handling of the fan assembly at some point, either while off the car or in the car....sort of like not knowing how to install bearings using correct installation procedures. Those tend to fail much sooner.
#21
Its unfortunate the fan cannot be removed without loosening the whole assembly, otherwise I'd take it to work and have them go all out on it in the labs...X-ray and whatever else the NDT labs do.
#22
Hi guys,
Just to cross reference this, the fan on my 964 disintegrated earlier today. Here's a thread on the 964 board:
https://rennlist.com/forums/964-foru...tergrated.html
There was no warning of the failure at all, just a really loud bang!
Andy
Just to cross reference this, the fan on my 964 disintegrated earlier today. Here's a thread on the 964 board:
https://rennlist.com/forums/964-foru...tergrated.html
There was no warning of the failure at all, just a really loud bang!
Andy
#23
These fan failures make me think of the early 911s--setting the timing was done with an old-school timing light, engine running at 6,000 rpm (fan probably spinning at 9,000), with your head pretty darn close to the fan in order to see the timing marks...
#24
Just for info sake... I just bought a 95 cab and 1 of the very few records that went with the car appears to be the same failure. I found a 2 inch piece of blade sitting down in the shroud (general engine tin to chassis shrouds) Looks like the repair cost 2600 bucks. New fan,shroud,pulley,belts,sensor,alternator... This was at 78,000 miles.
Curt
Curt