The Cal-look Lounge

There was an interesting article in the Dec. 2011 Cycle world magazine that was discussing this topic. The article was about air cooled BMW bike engines and the next generation BMW R series engine(s).  The article goes on to say that the latest and next generation of these engines will now be water cooled, and that these engines have “outgrown” being air cooled.
The article has some interesting points, and things to keep in mind that definitely relate to our beloved air cooled VW Hot Rod engines. It goes on to say – “Displacement increases as the cube of dimensional change (volume), while the surface area available for cooling fins increases only as a square (area). As heat produced is proportional to the displacement, it is thus possible for an engine to out grow its’ cooling capabilities.”

After I read this I started to think about the direction that some have taken building 3 liter plus engines.  I know that some have already done this with good results but I wonder what the limitations of displacement using VW tin ware are for our cars?  I’m referring to cars that can be driven in traffic and the highway for extended periods of time without over heating, not trailer queens or cars that are driven for 5 miles and then parked at the burger joint.  I have to admit that if I had the money I’d love to build one of these 3 liter 4 inch bore monsters but would hate to end up with something that would run too hot when driven on the street.

What do you guys think about this?  Discuss……
 8)

Excellent question and observation and ones I have given considerable thought and consideration/planning.
Unfortunately, I have NO EXPERIENCE with this subject so far!
One thing differing from the situation with BMW's concerns is in the application of our engines, we are not simply relying on the stock cooling system any longer. One will not be able to use the stock oil cooler, such as a 'doghouse', case mounted cooler. For oil cooling, you will have to implement an external cooler(s) of some type. So, we are increasing the 'limitations' of the stock systems capabilities!
That being said, the main and most common limiting factor I have found in multiple conversations with those that would and do know, is cylinder head design. Most of the castings made today that have the material and are capable of the dimensions for such a large bore lack the cooling fin area necessary to maintain suitable temperatures during daily or extended driving; most Superflow type heads have fewer & thicker fins.
So, the key element for a successful and workable solution would be to either find a design that absorbs less heat from combustion and exhaust, or one that is capable of dissipating greater amounts of heat through increased cooling fin area.
The two I have found desirable are AngleFlow heads and the JPM MS230.

More on this later ... enjoy the day.
TxT