<VV> Timing issue.

[larry@forman.net]

Hi Chris,
As Matt says, this is detonation.  This is REALLY bad and if you continue driving it with that happening, you will damage the engine very
shortly.  Learn to listen and identify that sound and make sure it does not happen.  You certainly should run higher octane immediately and
here are some other things you can do:
1. Make darn sure all the covers, engine surrounding seals, etc. are in place so the engine runs as cool as possible.
2. Retard the timing a few degrees and see if that helps.
3. Take a hand vacuum pump and test the vacuum advance module and see when it starts moving.  It should not start moving until about 9 or 10
inches of vacuum.  I bet it starts moving at 6 or less.  A "fix" is to remove it, take a 5/8 or 9/16 inch deep socket and dimple the end
where the metal hose pipe comes out.  Test as you do this a little at a time and see if you can make the vacuum advance kick in later.
4. You might have carbon inside the combustion chambers.  You could CAREFULLY decarbon the engine by SLOWLY pouring in a small stream of
water from a soda can while running the engine at high idle and making very sure the engine does not die.  You should get clouds of smoke
from the engine letting you know that the cleaning process is working.
5. Deflash the cylinder heads so they run cooler
6. Richen up the jets from maybe 0.051 to 0.053 or 0.054.  

There are more things you could do to cool the engine and make it run better.  Naturally, a tune up and rebuilding the carbs should be done
if they have not been done for a while. 

--Larry

On Wed, 16 Jun 2004 15:47:36 -0400, chris czepyha wrote:
> My 65/110/pg  usually drives very nice.  
> 
> Every once in a while it chunks trying to accellerate, and sounds like a
> roller coaster going up hill while trying to accellerate.  I will try
> putting in a tank of preimum. 
> 
> It behaved very nice at the cruise, by the ocean, driving a mile up the
> road, it started the above symptoms.  It was humid yesterday, not so much
> by the ocean with the breeze.
> 
> I think I should check the dwell and if needed advance the timing a
> little. 

Larry Forman