HEI and External Voltage Regulator

[cleszkie]

This is a question that I should probably post in the electrical board, but I have had good luck with the advive I've gotten with the Blazer owners, so here it is:

I have a Blazer that I want to keep very original, down to the external voltage regulator. The problem is, I want to be able to swap out the points distributor on occaision for an HEI unit without cutting up the wiring harness. However, I understand that HEI modules do not like voltage spikes that can occur with external voltage regulators. I plan on using the original voltage drop power lead from the ignition to energize a relay, which will provide direct power from the battery to the HEI. My question is, will this setup prevent voltage spikes to the HEI, or will the spikes still be seen at the battery (I suspect so)? If so, are there any sort of in-line voltage spike buffers that I can install to prevent ignition module damage?

[Blazer1970]

I have been running an HEI with the stock external regulator for years with no problems.

[cleszkie]

Blazer1970 -

You have been lucky. I have an early F**d Bronco that I can't seem to keep an external regulator from producing a spike for more than a year at at time. This wipes out my HEI ignition module so I have to buy a new voltage regulator and ignition module every time. Looking to save ignition modules in this Bronco and my Blazer project if I can.

[markedwin]

If you want to keep teh voltage spikes down, I am a electronic technician by trade for over 10 years, If i had to guess the voltage coming to the hei probably isnt spiking more than 18-25 volts considering we are working with a 12volt system, I dont have a system like you to test it on but with my knowledge if you went to radio shack and bought a capacitor anything of the range 2200 uf /50volt and put it in the system in the proper polarity it should eliminate the spikes you may have to increase the uf on it to get better filtering if need to be.