[george kujanski]

Never had a hei module die in several cars up to 200k miles and then some. Changed caps and wires like normal maintenance items.

Had a Yamaha 750 triple wth 3sets of points to adjust. Never want to deal with points again.

George

[Tom Vaught]

Maybe I just would up with a POS 78 Trans Am ignition system- (several times).

That was the only vehicle I ever had that has had ignition issues, None with Ford vehicles, other GM vehicles, or Chrysler vehicles.

Tom V.

[Schurkey]

Originally Posted by Tom Vaught

Maybe I just would up with a POS 78 Trans Am ignition system- (several times).

That was the only vehicle I ever had that has had ignition issues, None with Ford vehicles, other GM vehicles, or Chrysler vehicles.

My experience has been that the HEI and the Chrysler 5-pin (later development was a 4-pin replacement) electronic ignitions were tremendously reliable with the HEI surpassing the Chrysler in most cases AFTER the HEI had a couple of years of development.

An HEI can repeatedly fail the module when the in-cap coil gets hot enough to affect the insulation on the wires. At some point the coil resistance becomes low enough to pull too much current from the module, and the module fails.

The more-common problem was mechanical--the weights and pivot pins of the HEI centrifugal advance wore out. All the precision of the advance mechanism vanished. Without the need to remove the cap 'n' rotor to replace points, the centrifugal advance was never lubed.

I saw more failures of the Ford fender-mounted module and wire harness connectors. I think they were called "Duraspark". It may be that the same sort of ignition coil issues were behind the module failure, but I really suspect that the modules themselves had design or construction problems. As I remember, they were potted so there was no repairing them. The earliest GM fender-mounted modules could be disassembled to replace transistors or whatever. They were not a popular option. I've seen photos of the Delco/Pontiac "Unitized" ignition where all the plug wires were tied together at the distributor. You burn one plug wire on a header tube, and you MUST replace all eight as an assembly. Good luck finding parts for the "Unitized" ignition now.

I remember lots of stories about '70s-era electronic ignitions where extra modules were kept in the glovebox or under the driver's seat for roadside repair.






While there's some novelty value, when it comes to genuine 1974-era HEI distributor rotors (black plastic rather than the later white), and HEI coils, (no separate black ground wire, just the red, and the yellow or white wires) or Duraspark modules, if they were giving them away for free, I wouldn't walk across the street to get some for actual use.

The Chrysler electronic system may have been nicely reliable, but it was not a "high energy" style. The '70s Chrysler electronic system put out not one bit more power than their previous points system.

[geeteeohguy]

I run NOS Delco points I have stockpiled over the years. 106 and the 112's. The 112's have a stiffer spring and are better for very high rpm work, and came in the Z28 and other high winding engines. I've never had points bounce with the 106's in either of my GTO's. Use either old NOS Delco or a high quality replacement....not Wells. Points last me about 15,000 miles. Filing them is a waste of time. Replace them when worn or pitted.