<VV> 102 PG idle adjust

[Rick Loving]

cmot at ix.netcom.com wrote:

>
>When I was tuning up distributor ignition GM's one item that I always used
>to check whether modern HEI or points, especially if the engine was cold,
>was the cyntrifugal advance mechanism. What I found on older, high milage
>engines was that the lubricant on the distributor shaft between the shaft
>and the cam lobe mechanism would varnish up and stick, not returning to the
>fully retarded position at idle. 
>
>Take off the distributor cap and twist the rotor and release, it should snap
>smartly back. If the return is slow, or quick with the last part moving
>slowly like one of those slick new soft close drawer mechanisms they put on
>kitchen cabinets these days, your lube has seen better days and needs to be
>replaced. If the engine is hot on bad lube it will appear to work ok, when
>cold it will work slower or not at all in severe cases.
>
>This has the effect of causing inconsistant timing settings and idle speeds.
>When it heats up the unit will advance and retard more normally. When the
>engine is run cold the advance will apply but the springs will not be able
>to return the cyntrifugal advance to the idle rest position. It is not a
>weak spring issue. The advanced timing will cause a higher idle. If you
>re-adjust the idle speed and or mixture, you will be chasing your tail and
>wondering what the heck is going on. Luckily because of the Corvairs gear
>driven cam you do not have to factor timing chain wear into this sort of
>diagnosis which was another issue I used to see on other engines.
>
>If because of the sticking cyntrifugal advance you are setting the timing
>incorrectly. What might happen is that after warming up fully the mechanism
>frees up enough to work somewhat properly. You shut down the engine and it
>returns to base timing, the lube re-hardens and everything cools down and
>locks in the new position. You restart the next day and the choke and fast
>idle takes care of initial performance issues. Once choke comes off you find
>that idle is lower and you have a hesitation from retarded timing, that is
>until the engine warms up a bit and it start to advance some, but
>performance it is not entirely correct because the timing was never set
>correctly through no fault other than not noticing this issue.
>
>I used to see this problem a lot. You have to pull the distributor, remove
>the drive gear and slide the whole thing apart on some distributors. It's
>been so long since I did the early Corvair distribuors I don't recall if
>they were assembled the same way (some makes of distributors disassemble
>from the top) but the problem was the same. I had inherited a stock of the
>original Delco distributor lubricant in large tubes, it was black with
>specks in it that made it look like some of the more modern moly greases
>available. What the original composition was I am not sure. I can get the
>part number if people need it. 
>
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