Quote:
Originally Posted by syr74
Are you serious? The valvetrain in an OHV design, by it's very nature, is vastly more covoluted than an OHC setup needs to be. In an OHC setup all I have to have is a couple of sprockets, a chain., the camshafts themselves, and a direct acting cam bucket to actuate the valve and the spring underneath.
On an OHV design I still have the sprockets, chain, and a cam, although I do have fewer of them, but then for every valve in the engine I have to have a relatively long and thin pushrod reaching up to a rocker arms that reaches across the head to actuate the valve. Those parts do their job, but they are relatively fragile and absolutely create a weak link.
Why would somebody build the OHC counterpart to a Top Fuel motor when they would know they can't use it? Several folks have petitioned to able to use the same in the past, but the projects never got very far because the NHRA and IHRA like their Hemi's as they are. As for the good old days, SOHC Ford big blocks did absolutely rule Top Fuel for a time several decades ago, before they were banned from competition.
Here is some food for thought for you. If OHC engines aren't a threat then why aren't they allowed?  |
Exactly. There are far better ways to make power than roots blowers on top of OHV hemi's, just like there are far better ways to make power than with carbs like in NASCAR. If rules didn't specifically rule out certain designs and parts, you would see OHC multi-turbo top fuelers and OHC direct injected engines in nascar.