Why does Chevrolet stick to pushrod's in their corvette engines?

[PowerMacG5]

My father is looking in to purchasing a corvette, and this has inspired me to look in to a lot of things about it. One thing someone asked me was why does Chevy stick to the pushrod in their corvette (and the engines derived from that), and I gave the old adage "If it aint broke, don't fix it." That got me started on looking in to how the pushrod works, because I never really understood, so now after looking it up, I have a question. Is the reason Chevy sticks to the pushrod because the single camshaft is driven directly by gears by the crankshaft, which means that the engine will go longer without need for belt changes? If I understand correctly, the camshaft that drives the pushrods is operated directly by the craankshaft by gears. In a DOHC or SOHC engine where the cams trigger the valves themselves, they are belt driven. Is that the reason, lower engine wear, or is there some other reason?

 

[Analog]

History! The venerable Chevy pushrod!

 

[notfred]

One camshaft is cheaper, lighter, and easier to build than two or four camshafts.

 

[vi edit]

Because it works. And it's one of the reasons you can get 400+ HP in a $45,000 car.

 

[technogeeky]

In addition, there is evidence to show that much more power can be made more easily with this setup.

 

[Thegonagle]

The hood can be lower because the engine isn't as tall. There's more reciprocating weight in the valvetrain, so the engine can't rev as high, but that's made up for by tuning the engine for gobs of low-end torque.

 

[PricklyPete]

I feel like someone posted a great article discussing this exact subject. I can't seem to locate it through search...but maybe someone can find it...or maybe I read it somewhere else.

Anyway, the general point of the article pretty much pointed out that just because the push rod was old technology does not make it bad technology.

Sure SOHC and now DOHC have some benefits that come with the design, but also bring along negatives. The end result of the article was that each design is able to be tweaked to produce a kick'n engine. The Corvette's engine is a great example of a great pushrod engine. The Viper engine is also a good example. There are also many great examples of DOHC engines (see Mercedes, etc.)

 

[NFS4]

Why don't you read this and let this thread fall by the wayside?

 

[PowerMacG5]

Originally posted by: Thegonagle
The hood can be lower because the engine isn't as tall. There's more reciprocating weight in the valvetrain, so the engine can't rev as high, but that's made up for by tuning the engine for gobs of low-end torque.

Ah, never would have thought of the lower hood. I knew about it not being able to rev that high, but no need to rev high if you have tremendous low end torque, which the corvette does.

Originally posted by: PricklyPete
I feel like someone posted a great article discussing this exact subject. I can't seem to locate it through search...but maybe someone can find it...or maybe I read it somewhere else.

Anyway, the general point of the article pretty much pointed out that just because the push rod was old technology does not make it bad technology.

Sure SOHC and now DOHC have some benefits that come with the design, but also bring along negatives. The end result of the article was that each design is able to be tweaked to produce a kick'n engine. The Corvette's engine is a great example of a great pushrod engine. The Viper engine is also a good example. There are also many great examples of DOHC engines (see Mercedes, etc.)

Ah, thanks for the information.

Originally posted by: NFS4
Why don't you read this and let this thread fall by the wayside?

Blah, Car and Lier, I will read it anyway though, thanks for the link.

 

[JulesMaximus]

Is the camshaft in the Vette engine gear driven or chain driven? I thought most American pushrod V8 engines had a chain driven cam.

Never mind, I just read the article. I was correct. Vette cam is driven by a chain not gears.

BTW-Some OHC engines are also chain driven and some are belt driven.

 

[PowerMacG5]

Originally posted by: JulesMaximus
Is the camshaft in the Vette engine gear driven or chain driven? I thought most American pushrod V8 engines had a chain driven cam.

Ah, it may be, I wasnt sure. What I read said it was gear or chain driven, so I just said gear. Sorry about that if I was wrong.