<VV> Re: Porsche cooling

[JVHRoberts at aol.com]

There were a few Porsches with problems, yours being one of them. The time  
period you're talking about, for some bizarre reason, Porsche went from an 11  
blade fan to only a 5 blade fan! The idea was to crank up engine temps for  
improved emissions. Needless to say, the 11 blade fan became a VERY popular  
retrofit. 
This is a well known issue from about 1971 to 1978. 
Given that some 911s, turbos in particular, were belting out over 400 HP  and 
staying plenty cool, I'd say your 911T experience is NOT representative of  
most Porsches. 
 
In a message dated 7/31/2007 9:44:52 P.M. Eastern Daylight Time,  
crawfordrose at msn.com writes:


It  is unfortunate that Porsche has such a good reputation for cooling 
because  it isn't so much truth as belief. When I was 19 y.o. I owned a 72 
911T  which was the base model with iron cylinders. During a PCA sponsored  
dinner out of town we convoyed by Interstate 55 to have dinner about 40  
miles away. We all did 90-100 mph and my car began to seriously overheat  
after about 20 miles.  It had the dry sump cooling system but not a  remote 
oil cooler.  Now, the engine had 90,000 miles on it at that  time but the car 
was not able for sustained high speed runs in stock  condition.  Later when I 
had the engine rebuilt ($6,800 in 1985) I  had the recommended Porsche 
aftermarket oil cooler installed in the right  front fender and that seemed 
to resolve the overheating problems at  highway speeds.  The moral of the 
story is that the 911 fan did not  cool the engine enough to overcome high 
load conditions. 911 flat sixes  with iron cylinders do overheat unless there 
is additional cooling. Many  improvements in aluminum cylinder technology 
such as nikasil plating were  vital to exceeding 3.0 liters without 
overheating.  There are a  number of factors but the fan is not the 
determinant. Yet, I'd think  that  a 911 fan would cool my Corvairs o.k.
Crawford 


 



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