greg1990964

Nothing more annoying then salt trucks for not even an inch of snow. My town of Weston has more money then brains and salts at the slightest chance of moisture. I am sure the DPW boss trying to give the boys some overtime. I could drive the 964 tomorrow if they didn't salt. Annoying.....Ok, now I will go out in the garage and check my fan. Haha.

cobalt

Ken I will check but I might have some of the parts you need if you come up short.

964George

Just ordered an new fan as mines looking sorry for itself...
Paints lifting with signs of delaminating and corrosion on the leading edges of the blades

cobalt

You might consider removing the housing while you're at it. Needs some sanding and painting. The corrosion is already quite extensive but it is a non rotating part so it is less important.

Hard to tell the condition of the fan without stripping it first. Looks as though it was painted without proper prep and cleaning first.

964George

Was considering doing the housing, fan paint has lasted 2 years
I have some close up pics that show cracks at the base of the blades, hence why I went for a new fan.
Old fan is destined to become a garage clock

Mr.Alex

A really good powdercoater replied to me with this :


A few questions for those who have refurbished the fan:

1: Worth investing in three prong puller or would autozone rental be ok?

2: The bearing can be pulled off the shaft with the same puller correct?

3: Would shop press smoothly/safely press new fan bearing into fan.

4: After fan and bearing are together, would it all just slip back on the alternator shaft, or would I have to lug the whole alternator out of there.





Worst part is we didnt even get the rain or dusting of snow we were told, so they literally just threw tons of salt on the road for no reason.

cobalt

What does he mean by Magnesium is too soft? Average Brinell Hardness for both A356T6 aluminum and AZ91T6 magnesium is 70BHW. If he powder coats aluminum magnesium should work the same. I know some cast aluminum alloys will not anodize properly due to the high Silicon content which leaves white spots.

I have pullers although autozone or Pep boys rental should work if you don't need one. I used my puller to remove the bearing it all depends on the design. Shop press is fine it is all about properly supporting the fan to prevent any flex or cracking. I always remove the entire unit. Allows access to check everything and good time to clean and blow/vacuum out any debris. The 964 is far easier than the earlier 911's you also have a n access panel on top which the earlier cars do not. Not a bad time to check that the bushes are still good.

abarthguy

I think the powdercoater is woried about "outgassing" when baking some mag parts.
Had this happen with some Campagnola wheels. Finish had small bubbles.....

YaHoo!

When reinserting the bearing I put the bearing in the freezer overnight and in the morning put my fan in the oven at 185. Once the fan was up to that temp I inserted the bearing into the fan easily without a press.



Harbor Freight sells pullers cheap.

cobalt

Not sure why mag would outgas. If properly cast there shouldn't be an issue.

provoste

My powder coat has held up quite well, was coated in 2008. Recently had fan bearing and alternator bearing fail on track. Replaced the fan bearing with Rothsport's single belt conversion which eliminates the fan bearing. One less thing to go wrong in the future!

JB 911

I blasted and powder coated a brand new fan for two reasons. 1. I felt powder would last the life of the car, and 2. The finish on the new fans from Porsche is so so.

As per the outgassing, it can be a problem with mag, I don't know why. My coater was happy to do it though, having powdered lots of mag and said he just pre bakes it. ie bake, powder, rebake = no bubbles.

I also powdered my shroud. Then like several other rl-ers found after the fact that the tolerance between the fan and shroud is very small and my fan touched the shroud! Needless to say, I was disappointed to have to take a file to my perfect fan and remove the powder from the tips. I put some paint on the tips which is much thinner.

If I had it to do over, there is no way I would powder. I would paint. Think about it, the original ones hold up for 15-20 years with paint. Just take it off every 5-10 years and detail it up it may last forever with no risk of tolereance problems. So to answer your question, Paint, Paint, Paint, imo

Here is the oem finish, followed by the powder.

cobalt

Interesting. I have spent over 30 years manufacturing Mag sand castings and this is the first I have heard of outgassing issues with powder coating. They do it all the time to the 928 and 944 valve cover and intake housings without issue.

I would think Powder coating would be more susceptible to damage than paint. It makes a very hard covering but a solid impact will cause the extra hard coating to shatter. Most of the damage to these fans comes from debris being sucked into the fan at high revs and impacting the edge of the blade. No doubt this was the cause of damage to 964George's fan but it was also due to improper surface prep.

I would suspect how the coater is prepping the surface as being more the issue to why it is outgassing there is nothing in mag that should cause this and if cast properly should have no issue. Magnesium is not subject to porosity like aluminum. Microshrinkage is a concern but should not be present on a quality casting.

JasonAndreas

People might be confusing improper moisture control for magnesium outgassing?

cobalt

As usual, I think you hit the nail on the head.

Surface prep is critical and cleaning followed by drying in a warm air circulating oven should always be done about an hour prior to any coatings.