[Shotimes] motor sitting/weak valves

[Donald Mallinson]

Did check with the cam people.  I corrected the magazine people.

:)

Don M.



Kevin & Cheryl Airth wrote:
> 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 ???
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