GM HEI Distributors

[DJ]

Who knows about GM HEI distributors?<br /><br />In particular 1981 CCC.<br /><br />My question is: How much freeplay should there be on the timing advance weights?<br /><br />For some reason, I cannot get a steady timing reading. In addition, a remote tach. (inductive) will not hold a set rpm, no matter which plug wire I clamp the inductive lead on. It bounces between 600 and 1200.<br /><br />I am thinking that the timing is jumping around.<br /><br />The shaft SEEMS to be OK, yet the weights are pretty loose. The springs are still there though.<br /><br />Ideas?

 

[petryshyn]

Re: GM HEI Distributors

Hi DJ<br /><br />worn weights and pins won't cause your problem, as centrifugal force keeps everything side loaded at engine speed. Look to either a poor tach/timing light, or worn timing chain/gears.

 

[DJ]

Re: GM HEI Distributors

Hey Schematic.<br /><br />Nice to hear from you.<br /><br />I was hoping you wouldn't say that. <br />Wouldn't the timing chain show up as erratic vacuum?<br /><br />It runs OK over 1500, just the idle and acceleration are awful. <br /><br />The engine was rebuilt about 30K miles prior. Not by me, so I'm not too sure.<br /><br />I just can't get this thing to run smooth. (229 V-6). I know it's not the smoothest engine in the world, but it runs awful.<br /><br />New carb, plugs, rotor, cap, wires, EGR valve, air management valve, air pump, etc. We had to get the &*() thing to pass emissions, it did, but barely.

 

[SpinnerBait_Nut]

Re: GM HEI Distributors

Yea, I was gona say, slack in a chain will cause an unsteady reading.<br /><br />It don't take much to make a 3 to 400 rpm change in readings.

 

[Kinglg]

Re: GM HEI Distributors

Hey DJ, I agree with spinner. When it was rebuilt they probably didn't change the timing chain and gear. That would be the first thing I checked.

 

[Skinnywater]

Re: GM HEI Distributors

You can get a pretty good idea how much play is in the chain by rocking the motor back and forth.<br /><br />Remove the dist. cap and rotate the crankshaft pully back and forth. Watch how much angle of rotation is requiered to get the distributor rotor to move.<br /><br />I've seen flywieghts cause your problem though.<br />If you can safely wire them stationary with a paper clip or something. You'll be able to verify if this is your problem.<br /><br />Also check the harmonic balancer. Check it for broken rubber around the pulley. The timing mark itself could be moving.<br /><br />Does the timing jump around with vacuum applied and disconnected?