914-6 runs HOT - Part 2 Options

[767driver]

Some of you may remember my initial thread about 914-6 oil temps here...

http://www.914world.com/bbs2/index.php?sho...%20hot&st=0

I was hopeful that re-installing the ducts from the fan housing to the heat exchangers would solve my high oil temps. Well...it solved one of the causes of my high oil temps. Now that I have driven the car on 2 multi-day tours through California I can unfortunately report that the issue is not fully corrected.

With the benefit of hindsight I now know that as road speeds increase the airflow through the engine compartment is insufficient to keep the oil temp in check. Running through the gears on tighter 2 and 3rd gear roads are no problem. It's the more open 4th and 5th gear runs (high road speeds) that are causing the problem now.

Now it looks like we are dealing with 2 options. The first is to install a faster-turning 1.9 to 1 ratio fan setup. This will increase airflow through the engine compartment but will make more noise and take a few HP to run. The second option is to add an external oil cooler. The front-mounted cooler seems to be the tried-and-true solution but is expensive and invasive. Some folks have rigged up an external cooler with fan under the rear of the car.

I am soliciting thoughts, preferably from those with experience themselves, on these or any other options that may exist. I would appreciate any pictures of the various external oil cooler installations as well.

Many thanks,
Lee

[mepstein]

My belief is that 911 engines get most of their air cooling from the fan. They are often called air/oil cooled engines since oil cooling plays such a critical role. Adding an oil cooler, in addition to the engine oil cooler is pretty well known and well documented. In the 911, early S engines and all later engines benefited from a front cooler Later, when Porsche went to the 3.6 engine, they moved all the oil cooling to the front of the car. It makes sense.

It's actually very easy to add a front oil cooler without "cutting up the car".
1" holes drilled in the sill supports that run behind the rocker panel. Then 2 more 1" holes into the front trunk. About a half dozen 1" holes. Yes, that's all the "cutting" required. You will then remove the rubber plugs in the front trunk and the metal plugs that are seam sealed to the bottom of the trunk floor. Now you have airflow for the cooler. You might then want to create a cardboard template to box in the cooler and transfer the template to some sheet steel that hvac guys use for ductwork. But try running it open at first to see what kind of difference it makes.

Ok, I lied, there is some cutting required - you need to cut an opening in your front valance to allow air to enter the open holes in the front trunk. Radius the edges so it looks nice, similar to a GT valance.

[mskala]

You can get increased fan speed without going all the way to 1:9 to 1.
I may not be recalling exactly but some years ago I used the 80-89 fan and pulley
and with the original 914-6 crank pulley the math makes it about 1.6 to 1 vs. stock of 1.3 to 1.