<VV> Timing Question 110

[James Davis]

I find the 110 engines are the most sensitive Corvairs to octane 
number.  I suspect the problem is the distributor advance rate.  As 
the distribution springs go through heat cycles the loose some of 
their tension allowing the centrifugal advance to come in too 
early.  The 110 distributors, I have checked on the Sun advance bench 
have shown about 7 degrees at 2,000 rpm and 13  degrees at 3,000 
rpm.  These are distributor advance numbers multiply by two to get 
the crank advance.  With a true 9:1 compression 110 engine, I find 
the 12 degrees initial is about the max for the 891 cam.  I start the 
advance at 400 rpm and look for a linear rate to 2,200 rpm with a max 
total 12 degrees distributor advance.   I check the advance at 2,000 
engine rpm (20 degrees) and 3,000 rpm (28 degrees) with a dial back 
timing light.
     For the record, the Sun machine is not mine, but just down the 
road and I can use it anytime for free.
You gotta love the farmers that have a full machine shop and a generous heart.
Jim Davis



At 11:32 AM 2/26/2007, ChiefTAM at aol.com wrote:
>On my newly rebuilt 69 110hp, I am having a bit of a problem with
>pinging/knocking when I let out the clutch to start from a dead stop 
>in 1st gear  when
>the engine is warm.  I thought that the timing might be advanced a 
>bit  far, so
>I checked it over the weekend and it was set at about 13 degrees.   As the
>heads were cleaned up, I don't really know what the compression 
>ratio is,  but I
>am using 93 octane gas.  Seems like it doesn't have a great deal of  power
>down low when taking off, so I rev the engine a bit, and that is 
>when I  get the
>pinging/knocking.  I don't get it then accellerating in the upper  gears,
>just taking off from a start.  The car has a Pertronixs I. 
>Any  ideas on timing?
>Should I retard some more?  To what?   Thanks.
>
>Todd in TX