Hi
I am running a stock 194 L6
Clifford Intake
Holley 390 4 Bbl
later model GM HEI distributor.
Wiring is upgraded for HEI setup.
I am having trouble with the ignition timing.
Should I set up w original timing @ 8 degree advance.
If I set timing to stock advance, it pops back through the carb under moderate acceleration.
Any opinion?
Advice?  

several things to verify first

tdc at the #1 piston vs the timing mark... (outer harmonic balancer rings on sixes have slipped, maybe not  the riveted one that you might have)

the vacuum advance is working and not leaking...

the mechanical advance is free to advance and return...  grab the rotor and turn it agenst the spring tention..  then let it flip back... it should go all the way back to the stop...    the grease on the shaft drys up and stops the advance from working freely..

pull the rotor off and make sure the advance weight bushings are in good shape...


several minor things to also check... look at the back side of the rotor for spots where the high voltage can burn through...

look also at the external coil for circular dust marks on the center core close to the sides of the lamanations...   this is signs of high voltage leakage from the coil itself...

for other guys who may read this with later model optispark systems... change the ign coil before anything else to try to elimanate misfires...

this goes for most  coils with the E core design coils...

if you have a digital volt meter... set it to 200K ohm..... and read the spark plug wires..       they should read if good a number on the meter smaller than the length of spark plug wire in inches...   so a 24 inch spark plug wire should display less than 24 on the meter...    usually about 12 or 14..      

these checks i have describe take about 5 minutes or so....

if anybody has questions...post  a reply... or send a pm....


waynep712  

waynep712:
several things to verify first

tdc at the #1 piston vs the timing mark... (outer harmonic balancer rings on sixes have slipped, maybe not  the riveted one that you might have)

the vacuum advance is working and not leaking...

the mechanical advance is free to advance and return...  grab the rotor and turn it agenst the spring tention..  then let it flip back... it should go all the way back to the stop...    the grease on the shaft drys up and stops the advance from working freely..

pull the rotor off and make sure the advance weight bushings are in good shape...


several minor things to also check... look at the back side of the rotor for spots where the high voltage can burn through...

look also at the external coil for circular dust marks on the center core close to the sides of the lamanations...   this is signs of high voltage leakage from the coil itself...

for other guys who may read this with later model optispark systems... change the ign coil before anything else to try to elimanate misfires...

this goes for most  coils with the E core design coils...

if you have a digital volt meter... set it to 200K ohm..... and read the spark plug wires..       they should read if good a number on the meter smaller than the length of spark plug wire in inches...   so a 24 inch spark plug wire should display less than 24 on the meter...    usually about 12 or 14..      

these checks i have describe take about 5 minutes or so....

if anybody has questions...post  a reply... or send a pm....


waynep712

Somehow we spun teeth off the drive gear on the distributor.
Set #1 piston at TDC the timing mark was @ 0°. After pulling the cap to verify location of the rotor we bumped it around and the rotor didn't move. Pulled the dist out & the drive gear has been chewed out by the cam? not frozen or jammed, no visible distotion to the shaft
So now what do I look for?
Drained the oil, ordered a new distributor.

Thanks waynep712 for your assistance! it is a good reference to have.

sxbrubak  

a few things to do when dizzy drive gears get stripped....

check the oil pump... make sure it is not binding...  rig up a socket speed handle with  what ever it takes to turn the oil pump...   like a old extention that you grind flat to make a blade on the end and use a legnth of tubing t hold it on the center... some parts stores rent a oil pump priming tool...

i would also stop by a radio shack and buy a few tiny super magnets...  and push them into the oil pan  through the drain plug hole.. these will grab any metal particals that come loose...before they go through the pump...

take a flash light and look down the dist mounting hole in the block and examine the cam gear.... that might be damaged... you have to rotate the crank 2 times slowly to see the entire gear....

best of luck...