<VV> Dropped valve seat in Colorado

[Tony Underwood]

At 08:19 PM 5/14/2010, HallGrenn at aol.com wrote:
>
>Randy,
>
>That's the first half.   Apparently steel seats in aluminum heads  don't
>like the rapid cool down when you go down the hill after heating up on the
>climb.  So you want to shift up after you crest the hill so you 
>don't  descend
>in a lower gear at first which causes rapid cooling.  Let the heads  cool
>off gradually after the hot climb.
>



I can attest to this, after that mountain climb on the way to the 
Asheville convention in the Corsa ragtop and the aggravating trip up 
the mountain behind a dump truck that managed the perfect speed to 
cause me to either lug the car in 3rd or over-speed the engine in 2nd 
until I crested the top of the mountain with a hot engine and was 
able to pass him, and then faced that equally long downhill on the 
other side, behind another heavy-laden semi-truck with brakes so hot 
they were smoking and stinking up the landscape, a while before I was 
able to get around HIM with my own brakes getting hot so I ended up 
gearing down which of course supercooled the engine...  and a valve 
seat came out not long after getting away from the mountain, which 
meant I had to pull into the host motel all shaky and going 
clatter-clatter and providing passers-by with entertainment the 
following day with an impromptu tech session as I pulled it all apart 
to replace a head in the host motel parking lot.   Good thing vendors 
were everywhere...


I never allow a 'Vair engine to supercool like that again, overheat 
the brakes if need be, much easier to replace brake shoes than 
cylinder heads.



tony..

PS:   thought I had it bad til I saw the fellow with the FC that 
ruined a transaxle getting there