| Author | Message | ||
     Rc4man |
Was watching Speed (Nascar TV) last night and happened to catch the Daytona 200 qualifier. The new XBRR qualified 9th piloted by McWilliams, and was impressive to watch. The bike is also an impressive piece of work from the press release I've seen. I was just surprised that with all that expense they opted for two valve heads. Honda (don't flame me), Weslake and others have all shown through the years that you can make pushrod actuated 4 valve heads work. | ||
| Mutation_racer |
just too let you know it was 8th | ||
| Rc4man |
Ooops! Yes it was. Even better. | ||
| Tricklidz |
http://www.superbikeplanet.com/2006/Mar/sp2/060309f.htm | ||
| Buellx1w |
Where are the Kaws? I recall in the 80's and 90's they used to be in the mix ? I have an X1W myself - I was just wondering... Kaw's used to be THE Speed bike, I'm surprized they aren't even in the top 20 Spyder  | ||
| Anonymous |
4 valve heads are a bad idea on an air cooled motor. The small web between the exhaust valves is very prone to failure. | ||
| Sarodude |
Anony- Would there be any benefit to a 3 valve (2 intake) head? -Saro | ||
| Jeffb |
Yes, but Fueling holds the patents on this. I guess Ford is paying the company to use a 3 valve head on its 4.6/5.4 engines. Mercedes has one and they refuse to pay. I guess they are in court over the design patent. Jeff | ||
| Blake |
Fueling holds a patent on a three valve cylinder head? Where is the new/novel technology in that? Pretty sure that idea has been around for quite some time, in theory and practical use both. | ||
| Jeffb |
Check it out. United States Patent 5,638,787 Feuling June 17, 1997 -------------------------------------------------------------------------------- Combustion chamber system having an improved valve arrangement Abstract An intake and exhaust system for use with internal combustion engines that uses two intake valves and one exhaust valve for each engine cylinder. Said three valves are preferably round and spaced around said cylinder centerline in said cylinder head. A spark plug is provided in said head on said cylinder centerline and/or between each pair of adjacent valves. For best results, said two intake valves have substantially equal diameters. Said ratio of said area of said exhaust valve to said total area of an intake valve of from about is about 45 to 65%. Said head has three substantially hemispheric depressions each housing one of said valves. Squish areas are preferably provided around said combustion chamber periphery. Said piston surface is at least partially planar and can have an angled or radiused periphery or may have a central recess corresponding generally to said valve region. This invention provides a fast and uniform lean burn, permits use of a high compression ratio and lower octane, unleaded gasoline and provides improved thermal efficiency. -------------------------------------------------------------------------------- Inventors: Feuling; James J. (2521 Palma, Ventura, CA 93003) Appl. No.: 592760 Filed: January 26, 1996 Current U.S. Class: 123/310 Intern'l Class: F02P 015/02 Field of Search: 123/310,256,279,661 | ||
| Sarodude |
The patent seems to focus more on the combustion chamber and maybe even sub-chambers rather than the fact that there are three valves. Anyone here familiar with Honda's CVCC motors? They had a little pre-chamber arrangement which ignited a richer mix provided by an auxiliary intake valve and a main chamber which received a lean mixture through the primary (?) intake valve. Stratified charge. Feuling makes no mention of charge stratification. I did have a mid 80's CRX with a three valve head and SOHC. Wonderful car with a very nice motor for its time. Dunno what I'm saying. I'm rambling. Bye. -Saro | ||
| Jackbequick |
"..Anyone here familiar with Honda's CVCC motors?" Compound Vortex Controlled Combustion, those were great cars. Some of the early two liter two door models made it back to the U.S. in the hands of servicemen. A buddy of mine in San Diego had one (a left hand drive model) and it was like a sports car. Lot of fun to drive, excellent handling and power. They turned it into a 1500cc four door for the U.S. model IIRC. My old North Dakota farmer uncles used to put little external combustion chambers on their old John Deere tractors. Those screwed into the spark plug hole and then the spark plug screwed into that. Its effect was to slow down and draw out the ignition and burning cycle to avoid hammering the bearings in those old timers to death in short order with those butt kicking modern fuels used in the newer tractors. Most farms up there had two or three widely spaced generations of tractors and any tractor that did not make it through two or three generations of farmers was not worth a darn to them. Jack | ||
| Chauly |
Didn't Dan Gurney and Weslake have three-valve heads back in the late Sixties? | ||
| View_from_afar |
Four valve heads seem to work on Guzzi motors ok, Ducati's running a 3 valves head in the ST3 however with overhead cam and water cooling.  | ||
| Rc4man |
I'm old enough to remember the Weslake Triumph twin kits from the early seventies. They were later developed into the Nourish/Weslake racing engine in displacements up into the 900cc category and used for drag racing and circuit BOTT era racing into the eighties. They sure proved the concept. Smaller lighter valves and lighter valve springs with flat squish type modern conbustion chambers have the capacity to make HP in any engine. |
