HEI Module

BSAKing wrote:
> I had the same problem - here is some advice I got that may be useful to
> you.
>
>
>
>>I have a 76 vette and I had to replace the ingintion control module about 3
>>years ago - the first time since new.
>>
>>Now - today it is experiencing the same symptoms - it died on me travelling
>>along, let it sit for a bit while I checked it out and then away it went
>>again.
>>
>>When I replaced it, I did liberally apply the silicon grease to the back of
>>it. Now - the replacement I got from Canadian Tire (the equivalent of a
>>WalWart) and I am wondering if there is something else I should have
>>replaced at the same time? Or are control modules all not equal and maybe I
>>should have replaced it with one directly from GM?
>>
>>thanks.
>
> ================================================== =============
> It is always advisable to change the ignition coil when replacing a module
> on an
> HEI system. Usually the primary of the coil intermittantly shorts out
> causing
> damage to the module. Another possibility is your pickup coil. Every time
> the
> vacuum advance pulls in or releases, the pickup coil leads flex. There is
> just
> so much flexing a 29 year old pair of wires can take, until the strands give
> out. Disconnect the pickup coil, and then put an ohm meter across the pickup
> coil leads. Connect a piece of vacuum hose to the vacuum advance and apply
> vacuum to the hose. This will make the coil rotate. Watch for any
> fluctuation in
> the ohm meter indicating broken wires. By doing this, you will also find out
> if
> your vacuum advance is working.
>
>
Ten years ago I had the same symptoms on a '79 350. Pulled the
distributor and tore it down all the way. Replaced the module--didn't
fix the problem then found the intermittent pick-up coil wire mentioned
above. Also found red, rusty dust that was adding friction to the
advance mechanism. IIRC, the dust was coming from weight pivots on the
drive shaft below the advance plate. Dust was also in the cap/coil
area--maybe causing intermittent cross firing. Replaced the module,
pickup coil & cap. Cleaned the advance system. Used the old coil.
Worked OK after just those things. But now, I'd go along with BSAKing
and spring for a new coil and module.

Check for an oil spiral on the distirbutor shaft. Mine had one and it
was crudded up with little oil flow to lube the bearing.

There are some high-current modules for high current coils but with a
stock or OEM coil, a brand name OEM module should be OK.

Paul H.