1.6 rollers

[Timbers]

Why

Why not use aluminum rocker arms on the street? Whats the difference if you are driving the car on the street, or at a track? I don't understand?

...Tim

[fastTa]

Re: Why

Originally posted by Timbers
Why not use aluminum rocker arms on the street? Whats the difference if you are driving the car on the street, or at a track? I don't understand?

...Tim

Driving on the street exposes the valvetrain to prolonged heat and stress. Going down the track 1/4 mile at a time does not expose the valetrain to near as much prolonged heat and/or harmonic stress.

Aluminum is much weaker than chrome-moly steel so an aluminum rocker is much more prone to fail than a steel rocker if it is used on the street .

MOST chrome-moly rockers are just as light as the aluminum rockers anyway, so on the steet steel rockers are the ticket.

The full out race aluminum rockers are a bit lighter and will make a little more HP but they are for race only motors that don't see the prolonged heat and stress.

[Timbers]

Weird

Weird, you would think the rockers would only get to the tempature of the oil that is splashing all over them, which is a tempature it would get to no matter if it were on the street or the track.

Weird, I still don't get it haha! So what you are saying is aluminum rockers won't 50,000, 80,000 miles, or whatever of use? They are meant for runs down the strip, and thats it huh?

...Tim

[fastTa]

The key word in my previous post was PROLONGED!

The extended exposure to heat is the least of a aluminum rocker's worries. Aluminum rockers are much more prone to what is called "deflection". This is when the body of the rocker flexes due to the load being placed on it. Since aluminum is not as strong as steel it is much more prone to deflection and therefore more stress.

If you want to build a durable street motor, use a steel rocker arm.