<VV> Surging

[Dennis Pleau]

Here is the one I was searching for when I found the one I already posted.
This one is by Larry Forman.


> I think you know the answer, which is you ARE masking the real problem.  I
> suspect that your vacuum advance cannister's internal spring is VERY weak,
> which is what I see in nearly every one of these that are original.  You
> can likely "restore" it to proper operation by first checking if the
spring
> is weak.  Take a hand vacuum pump, like a Miti-vac and see if the arm
> starts moving before about 9-10 inches of vacuum, which it should not.  I
> bet it starts moving before 6 inches of vacuum.  If so, it would provide
> too much advance under high vacuum conditions, like light throttle
> acceleration.  So, remove the vacuum advance canister and place it into a
> vice or set it up between two bricks so the arm hangs down. Then take
> either a 9/16 or 5/8 inch deep socket and place it on the end over the
> nipple.  Bang on the end so it compresses the internal spring and then
test
> to see if the starting vacuum has increased.  Keep repeating until you are
> at the right place, then reinstall and test drive.  It should work much
> better after the "restoration".  If you alternate between the two sockets,
> you can compress the end and it will look almost like it was built that
way
> and worker properly.
>
> Additionally, you can take one of those new advance timing lights and
> calibrate the vacuum and mechanical advance characteristics with the
engine
> running.  With a new Dale distributor, you should be in excellent
condition
> for mechanical advance, but check and compare with the information in the
> CORSA Tech Guide. It provides information on the vacuum and mechanical
> advance characteristics for most Corvairs.  Pretty valuable information.
>
> -- Larry