<VV> Shrouds or No?

[Mikeamauro@aol.com]

"....eliminating the lower shrouds, some additional heat dissipation 
is gained ..."

I'm getting in late to this discussion, so, if I'm repeating previous 
information, please excuse...
To shroud or not to shroud: for me it's a seasonal thing. I live in Central 
Florida--which is actually hotter in the summer than South Florida--and I 
remove the lower shrouds (on all my Vairs) in late spring, reinstalling as the 
first cold fronts start arriving. This R&R process is about a 10-minute job coming 
off, and 20-minutes going back on.  It is worth the effort: having the lower 
shrouds off reduces cylinder head temperatures significantly, and, for me, 
makes the difference between engines that ping and those that don't. When I was 
leaving the shrouds on year-round, I was having to take ignition timing out 
during summer months to alleviate ping and detonation. (However, less timing 
generally leads to less low-end power and increased fuel consumption. Also, less 
timing, depending on how much advance is taken out, can sometimes actually 
cause an engine to run hotter.) I use premium fuel, year-round, in all my Vairs, 
anyway, so upping octane in the summer is not an option for me.   
Seasonal shroud use, in my somewhat humble opinion, is a useful compromise 
for the warmer climates....may not be necessary in, say: Northern-Michigan. 
As for increased wear with shrouds off, I theorize this is due to the engine 
being slow to get off the chokes and, combined with the rings never fully 
expanding & sealing, raw gas continually contaminates the oil...kinda like doing a 
lot of short trips-- never good for engine longevity. To preclude premature 
engine wear, and, of course, to have a heater and defroster, shroud use in the 
winter is a necessity.
If you got this far, thanks for listening.

Mike Mauro