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boofis 01-14-2005 04:12 PM

HOw does a twin cam work
How does a twin cam work? What does cam stand for? Camshaft? Just curious, sorry! Also, does twin carby just mean you're like pumping more air and fuel mixture or something :S?
Troy 01-14-2005 04:38 PM

Twin cams are used in overhead camshaft engines with hemispherical combustion chambers. Since the valves are angled into the chamber from opposite sides and the benefit of an overhead cam is best realized when there are no rocker arms, the only way to make it work is to have a separate camshaft for the intake and exhaust valves.

Twin carburetors means just that - two carburetors on an engine. The idea is to provide more flow area in the fuel/air mixing system so the engine can rev to higher speeds (more power) without being choked off due to too small a carburetion system.

boofis 01-14-2005 07:56 PM

THANKYOU :) That makes more sense lol! Now how does a supercharger work :S? Thanks man, have a good one!

Bandit1980 01-16-2005 01:10 AM

I thing you can found all info you need on supercharger section of holley carburator site

Max Keith 01-17-2005 01:23 PM

twin cams
Willys36, well done. HUZZAH!

farna 01-17-2005 03:08 PM

Great job Willys! Just one note -- not all dual overhead cam engines have hemispherical combustion chambers. They can be "pent roof" (like a house roof). That said, I do understand that the OHC arrangement is a must for Hemi chambers.

Supercharging is pressurizing the intake air, regardless of how it is done. When people refer to "supercharging", however, they usually mean a belt driven type. A turbo charger (techincally a turbosupercharger) is exhaust driven but does the same thing. There are two major types of belt driven superchargers: the big Rootes type "blowers" that were originally designed for diesel engines, and centrifugal, which are smaller and sit beside the engine. In essence the centrifugal supercharger is a belt driven turbocharger. It's more to it than that, but the basic design is similar. Most centrifugals have a gear drive to spin them up faster than possible with direct belt drive. There is also a screw type blower that looks much like a Rootes type, but uses two big "screws" to pull air in and compress it. The Rootes blower uses two slightly twisted, interconnecting "lobes". I'm sure you can find some pics on the net, likely at the link posted previously.

Take a look at This is a turbocharger turbine with a belt drive adapter. Note the small diameter pulley, needed to get the ting up to speed. I don't know what diameter pulley is used on the crank, probably the typical AC compressor size. You can't connect a pulley directly to the turbo shaft as the bearings aren't designed for the side load. So an adapter with heavy enough bearings is used in front of the turbine. 01-17-2005 03:14 PM

If you make that distinction then the new Chrysler hemi is more a pent-roof combustion chamber than a hemi.

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