Subject: Re: hydrogen ebrittlement

From: [email-masked] (Eric Perozziello)
Date: Thu, 13 Jan 94 02:18:15 GMT

>:	The rocker arms on the motor
>: 	of my dad's dragster are prone to break.  They are aluminum
>: 	with a hard anodize coating.
>
>A layer of anodization can provide convenient nucleation sites for
>cracks, however my first suspicion would be the rest of the valve train.
>How close are the springs to binding?  Is there enough spring travel
>left to allow a bit of float in the case of over-reving?  Is he running
>solid or hydraulic lifters, and if hydraulic, is he sure they're not
>pumping up to the point of binding the coils?  I assume these are roller
>rockers.  Are the pivots staying free, or could they be siezing?

Not to discredit this discussion (I'm learning a lot from it), but
I was told long ago that aluminum rockers are "disposable" parts
when used for these applications.  They just aren't made to stand
up to the kind of abuse they're given, for a long time.  The reason
you use them is to tweak the last drop of (engine speed) from the
valvetrain. 

Now, back to the regularly scheduled program.... (it's a good discussion).

-Eric

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Governments that don't trust honest people with weapons, deserve no trust.