Re: Valve Springs

["Dan Bocek" <dan@di.com>]

>How old were the valve springs which broke? Were these replaced when the 
>pistons were installed or were these the origional Abt valve springs when 
>they built the big valve head? 

The valve springs were not replaced when they did the original rebuild of
the engine, but why should they habe replaced them?  The head only had
about 30K on it.  I don't know if Abt put in new springs when they rebuilt
the head, but when Sport Wheels measured the spring stiffness of the old
springs (those that survived!) and compared them to a stock spring from a
10V turbo motor, they said that the old springs were about 30% LIGHTER
than stock!  This leads me to believe that Abt used the stock springs when
they built the head, and Audi upped the spring pressure in later model
years.

>Has John or anyone else everheard of valve 
>springs failing on a TQC?

Yes, as a matter of fact he has, but he's never seen a complication quite
as bad as mine.  He thinks that Audi springs from the early days
tended to break more than the later ones, as evidenced by their having to
repair more heads with broken valve springs on the earlier model turbo cars
versus virtually no problems on the later models.

>Another enhancement you could look into are some of these new coatings which 
>are applied to the internals of engines. An article I read recently (in a 
>recent issue of Hot Rod) talked about applying a low-friction self 
>lubricating dry film polymer coating to valve springs. They said that 
>uncoated valve springs usually run 30 deg hotter than the oil and a coated 
>spring only runs 20 deg hotter which increases the life of the valve spring.

>They also mentioned other coatings for other engine parts like low friction 
>oil-shedding dry film, heat dissipating and thermal barrier coatings. It 
>seems that Top Fuel and Winston Cup teams have been using this technology 
>for quite some time. Has anyone else been looking into this?

These lubricants wouln't happen to be Teflon based, would they?
-- 



                                                    Dan Bocek
                                                    dan@di.com