The SAE paper is a great source, and if you read the factory service manual carefully you'll learn even more.

You'll also find that there are still a number of compromises in this engine by looking at both these sources of information. Some of these compromises beget other compromises, which means there is some room for improvement on a level that some might not believe is possible - but it won't be cheap.

BTW, those scissor gears are not unusual in and of them themselves, but you don't see them being used in cam drives all that often. I've held one in my hand and played with a disassembled one, and they are absolute jewels - incredibly small and precise.

UL

 

The rocker arms are injection molded metal. I believe the main purpose of this is more precise parts with less machine finishing work needed. The big parts such as the various engine block components are DIE Cast for greater strength.

One interesting tid bit is that engineers at Honda claim that the limiting factor on the engine RPMs is not piston speed as you would imagine but creating too much heat in the valve springs due to the hysterious (sp?) effect. Like the heat that is generated when you bend a piece of metal back and forth. They counter this with a steady oil supply through the hollow cam shafts.

On an engine without valve springs (F1) piston speed is still not the limiting factor, Honda claims they could spin the engines much higher if it were to an advantage to do so. The limiting factor is moving the fuel charge in and out of the cylinders fast enough for complete combustion in a naturally aspirated engine. They are not concerned with blowing the engine apart due to high revs. They have the technology down pat to deal with those forces now.

 

Not to contradict you Bieg but do you know anything about casting or forging processes?

Actually injected metal molding IS die casting. And die castings are the cheapest junk casting available on earth; the weakest not the strongest. This is why the process is used to make Hot Wheels cars and is of limited us on a real car (reserved for the likes of trim items). In fact the rocker arms are a manufactured using a permanent mold process. A negative mold is used to make a "wax". The wax is then coated with a ceramic slurry, thermal cured, and the wax melted out. Hot metal is then poured into the ceramic mold. The ceramic is then blasted away (using water) and a very accurate (within thousands)dimesional replica of the negative mold is left behind. As for the large castings; these are cast is sand, a process known as Sand Casting. A pattern usually of wood is used to form "green sand". The sand pattern is then cast and the final casting is produced. Dimensional stability is much less in sand (tens of thousandths).

Note: If you did try to die cast an engine block you would end up with a piece of swiss cheese that would leak oil at every passage and have no structural integrity at all.

 

Perhaps you should write a rebuttal to the SAE paper titled "Development of the High Power, Low-emission Engine for the Honda S2000". I am sure the guys from Honda R&D don't have a clue about castings either because right there in sect:3 it says

"The cylinder block is die-cast aluminum featuring fiber-reinforced metal (FRM) sleeves which combine to achieve a higher level of rigidity and dimensional compactness."

Guess they know something about casting that you don't.

 

I love this board ! So many intelligent and well educated members to provide for our intelectual stimulation. And the snubbing is of equally high level.