H-D Water Cooled Heads for Touring Bikes

I just finished checking out cad drawings of a head cooling system done by Harley-Davidson. Two small radiators integrated into an Ultra Glide's lowers, a pump, tucked away lines, and two small ports in each head for the coolant to flow into and out. The flow through the head is a simple 'C' shape.

 

Showing the passage through the Head. And the overall layout.
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Hmm...that's a lot of plumbing and parts just to cool the exhaust seats. It's time for a proper redesign if the exhaust side needs cooling that desperately.

What is the history of this system? Is this an exercise from the past? Or...is this Harley's future?

 

But the thing is Harley will encounter massive customer resistance if they change the look of the engine in any significant way. Cooling only the parts that need cooling for emissions will give them another decade or so before complete water-cooling is implemented.

 

Flathead, Knucklehead, Panhead, Shovelhead... and this is going to be... ?

 

<snicker, snicker>

 

They are on "Evo" now! No more "Head" for the motor company. ;-)

 

Au contraire, I've heard that the Evo has been called the Blockhead... and after that the Twin Cam, or TC, is referred to as the Twinkie or Fathead.

 

Wethead.
Maybe I should copywrite this?

 

This has been kicking around for a few years now. I wonder if it will ever make it to production.
It looks like the cooling localizes on the exhaust port and valve seat area only, which is obviously the area where the most heat is generated in the cylinder head.

 

Thanks, I didnt know. I stopped at Shovel Head.

 

Awesome, I am sure you are right about this.

 

Curious why only the heads and not the cylinders? Not that it matters, Harleys have always been more or less air-cooled, and there's the V-Rod if you want a water-cooled twin.

 

I'll take a stab at answering these questions.

The "head onl"y for 2 reasons, is my guess. 1) They want it to look as much like a traditional air cooled engine as possible, and 2) The head and the piston are where most of the head is generated from the combustion process. If you can control the head temperature you can help minimize overheating. In a traditional air cooled engine there is a piston jet that sprays on the bottom of the piston to help transfer heat from the piston to the oil and there are very few if any oil passages around the combustion chamber in the head. Thus, there is a lot of heat buildup around the combustion chamber in the head without adequate air flow.

The Vrod engine is a much much different animal than the Twin Cam. It is a short stroke, large bore (oversquare) engine design which requires higher rpms to extract the power. Peak torque is in the 6500-7000 rpm range (rev limit at 9000 rpm) on a stock stroke engine. The twin cam, on the other hand, is a long stroke, small(er) bore design that is very torquey with peak around 3500 rpms and rev limit set at 5500.

We all know that Harley has trouble breaking with tradition

 

The other main difference between the Twin Cam/Fathead/Evo/etc engine and the V-Rod is that many Harley traditionalists hate the V-Rod and do not consider it a real Harley for all the reasons you mention.

 

Oh definitely. I've owned 4 Harleys, and the anachronistic design is part of the allure.

Figured that was driving the liquid cooled heads, but honestly, I've never had an issue with my bikes in terms of overheating. One thing that is a problem with the smaller bikes (Sportsters) is that the heat from the engine can get uncomfortable, but nothing serious.

 

Yes, understood (although I happen to dig the V-Rod).

Not sure how many traditionalists would go for a liquid cooled head design. I recall that the Twin-Cam had some skeptics, although I guess that's to be expected...they are fully accepted now since that's what they make!

Too bad the Revolution engine (V-Rod) couldn't have been used by Buell...I'm still a little peeved about how that all went down.

It took a company like Roehr to do it - although at $40K, you could just purchase a VR1000...