<VV> (no subject)
Mikeamauro at aol.com
Mikeamauro at aol.com
Mon Apr 20 15:08:25 EDT 2009
"...I'm going to reduce the timing advance further later today. but what's
your advice on the best timing range for this situation?..."
Jeff...
Reducing timing meets a point of diminishing returns: moving much away
from factory recommendations reduces fuel economy. And, taking too much timing
out can actually make the engine run hotter (read: and make it more prone
to pinging and detonation... the thing you are trying to get rid of). Low
octane fuel, hot spots in the combustion chamber, and excessive engine heat
all contribute to pinging (as does too much timing and a few other more
esoteric things ). Assuming you have a basically stock engine, following are a
few things to try: have you removed the lower engine shrouds and tried
the cup of water down the cabs while running "trick" to de-carbon the
combustion chambers (don't try this unless you understand the concept/method,
completely)? I live in Florida; one of my Vairs is a 110, PG with A/C (a
combination very prone to produce ping). I run 18-degrees of advance year round;
however, lower shrouds are off April thru November. This reduces engine
operating temps by about 15-20 degrees, and is just enough to get me through a
typical Florida summer. If, after de- carbonizing the combustion chambers,
and removing the lower shrouds you still get ping, more drastic measure
are in order (not necessarily in this order): check and deflash the cylinder
head cooling fins; reduce the combustion chamber quench space (.032 is
optimum); verify carbs are not running too lean; try different vacuum advance
units (or modify internal spring action of yours) for later application of
vacuum advance. Corvairs were designed for higher octane than is presently
available from the corner gas pump; hence, extra care must be taken in other
aspects of engine operation.
Mike Mauro
**************A Good Credit Score is 700 or Above. See yours in just 2 easy
steps!
(http://pr.atwola.com/promoclk/100126575x1220572844x1201387506/aol?redir=http:%2F%2Fwww.freecreditreport.com%2Fpm%2Fdefault.aspx%3Fsc%3D668072%26
hmpgID%3D62%26bcd%3DAprilfooter420NO62)
More information about the VirtualVairs
mailing list