[Shotimes] motor sitting/weak valves

[Kevin & Cheryl Airth]

I think you should check with people in the cam business and not the car
magazine business!

To answer your question correctly: No fatigue BUT. There always is a but
right? This is from Crane Cams Technical department. The ONLY way to tell if
the springs have taken a set is to check the spring seat pressure with a
spring checker. They can and do take a set but not always. The higher lift
cam you have and the more Hi-Po material the springs are made out of the
more likely this will happen. In other words a stock engine and springs will
probably be OK. Crane recommended for a engine sitting several years to pull
them and check.

I personally would run it and see if it makes noise. I think your spring
would have to get VERY weak before you would hear a noise. I think your
first symptom would be some valve float at high RPM's and might be hard to
detect with a OHC engine?
.
.




> I addressed this issue with the tech guru at Road and Track.
>
> He finally agreed with me that a spring sitting still, even
> fully compressed, gets ZERO Fatigue stress!
>
> Only movement wears out springs, and they don't really take
> a set from being compressed.  It is the repeated motion that
> breaks down the springs eventually.

> > This motor has been sitting for about 3 years and my expierence with
motors like this is that the valve spring that is fully compressed can get
fatigued and weak .. creating a light intermintient tap.
> >
> > My question is does anyone have any ideal the max time frame that a
motor could sit ( +/- ) before this event would happen ???