Distributor tuning tips by Smith29 on the MTS board
- Is you centrifical working properly with some stiff springs? If you
have weenie springs put heavy ones on. Does the advance turn free as
a bird with no springs? If not you have to get some thin oil into the
bushing and get it FREE!!!
With stiff springs on see that the rotor returns to the stop when you
rotate it ccw and then release it. Make sure it does.. If it dont
it's hanging up from corrosion and you need to get thin oil into it.
Don't use WD-40. It evaporates. Use thin oil maybe with some kerosene
till it rotates free as a bird, this is utmost important....
Put stock springs on and disconnect vacuum to advance and plug line.
Time engine to 8 deg btc.
race engine and see it return to 8 deg.
Carefully remove cap and see if you can rotate rotor ccw. It should
move very little meaning it's working.
Now put a lighter set of springs in and idle the engine again at 600
Is timing still 8 deg?
If it is you can raise rpm and see if you get 34 deg approx at 25-
If not go a little lighter spring on one side only. Check each time
you change to a lighter spring to see 8 deg at 600 rpm.
If it works out you get 8 deg and 34 deg where you want it, you are
Now some distributors wont give the 34 deg no matter what.
On those you have to shorten the counterweight arms that touch the
center arm or cam.
A 69 dist. will give the advance wanted and a 76 dist needs the arms
ground down about an 1/8 in. to do the proper advance.
Then if satisfied with your work you hook up the vacuum. If it's
connected to a ported outlet on the carb go to direct manifold vacuum
( MAP ) it's called. That will give you vacuum advance while idling
and the engine runs cooler and you will save gas. The Ported trick
was to heat up the catcon and keep it hot in town so it would work
but the heat and the fuel consumption are not desireable and the
engine is more risponsive at low rpm with MAP.
A weak point in the dist. is the shaft for advance wants to sieze up
from engine sweat. You have to periodicly see that it is free as a
bird and you can do that simply by checking the base 8 deg without
vacuum at 600 and 34 deg at the higher rpm.