<VV> Detonation

[Richard Widman]

The vacuum advance should not be pinched off.  

Run a tank or 2 of gas with Techron fuel system cleaner to get carbon off
the pistons and heads, clean and deflash your heads and cylinders, check for
the right mixture.

Pinging is from hot deposits igniting the mixture too far before TDC.
Deposits maintain heat and reduce the cylinder space, increasing compression
to where you either need to get rid of them or move up to higher octane gas
to retard the rate of ignition.  Pings cause damage to engine by pushing
backwards on the crankshaft.

Reconnect the vacuum line and retard the timing slightly until there is no
ping.  Then run the tanks with Techron and see if you can advance the timing
any.  The correct timing is what gives you the best power without ping for
your given altitude and octane.  The higher you go with either of those, the
more advance you should have to get the most power and least damage.  I have
always used the timing spec as a starting point.  There have been days when
I've advanced the timing 3 times on a trip that increased 10,000 ft in
altitude during the day, retarding it on the way back.

 

 

------------------------

Richard Widman

www.widman.biz