[T3] cooling fan engineering

[Dave Pallo]

I rebuilt my first VW engine last winter. (block and crank went to Rimco -
Russ Wolfe rebuilt heads - new jugs & pistons & cam etc. from Berg)

I did all my break-in running last spring and logged a total of about 1500
miles on this motor last summer. I had a strange noise coming from around
the back end of the motor. It was a metallic noise that would change with
motor rpm, but it was not a consistent noise. I'd be driving down the road
with no noise, and then coming to a stop light in town I could hear this
kinda rattle. Then at the next light - no noise. To me it had something to
do with the cooling fans, and these are the fans that came with this motor
(not the fans we've been running on Elwood). I checked and checked and
checked for a loose fin, or something touching the fins, but found nothing.
So over the winter I tore it down enough to remove the fans.

 

What I found was evidence of ground rust "dust" from around where the
stamped metal fan is riveted to the machined hub. I cannot feel any play or
looseness there - but the rust dust told me there is some rubbing going on.
I replaced this fan with Elwood's original fan, and now the noise is
completely gone.

Since I wasn't going to use this fan anymore - I drilled out the rivets.
What an amazing amount of engineering that went into the cooling fan! I
never knew there were rubber bushings with what I'm assuming are shim
plates. I'll bring this fan to display at the Invasion so everyone can see
just how complicated our metal cooling fan really is, and so y'all can help
me figure out what went wrong with it!

 

Dave Pallo

'72 Square ~ Elwood

Fairport, NY

 

 

 

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