<VV> timing specs

[Sethracer at aol.com]

In a message dated 8/18/2013 2:40:02 P.M. Pacific Daylight Time,  
stevetdunn88 at yahoo.com writes:

Greetings corvair owners , my question is on timing, recently tuned  up our 
68 monza 110 , i do use additive in the gas , engine knocks the second  u 
hit the the gas, timing ? Where should it be ? Thanks for your help  !
 
Your phrase "Where should it be?" is a problem. By 1968, Chevy had  
installed smog pumps on all of their Corvair motors. Along with those pumps come  
some of the goofiest ignition timing advance curves ever used. Some  1968 
models specify 4 degrees of initial timing, relying on a low idle and  a lot of 
quick mechanical advance in the distributor when the car comes off  idle. 
The problem with that is, after 40 years, the engine is no longer idling  at 
500 RPM. It could be idling anywhere, easily up close to where  the original 
mechanical advance has begun. You can chase your tail on these  motors to 
try for a low idle and correct advance. The 1965 110 motor  was not so 
encumbered. If you can find a 1965 110HP distributor, (P/N 1010319)  you can set 
the car to a better initial advance - say 10-12 degrees - then let  the more 
conservative mechanical advance kick in at the proper time. Note that  the 
110 PG motors were always problematic for ping during upshifts. You may have  
to shuffle the initial timing setting around even then. The 65 manual calls 
for  14 degrees initial. The stock mechanical advance still has zero at 
800RPM,  then adds 20 degrees by 4800RPM. The 68 distributor for the 140HP 
Stick has  20 degrees in by 1420 RPM. Do you know which distributor you are 
running? The  digits are stamped into the side. The last three digits are all 
that is needed  to ID the original application for the distributor, usually  
identifying the recommended setting. Or telling you to run the other  way! - 
Seth Emerson