White_Knuckles

Okay, so I purchase this "project" car and have been unwinding problems for a couple years now. I bought the car with clear knowledge there would be unforeseen secrets to come. The car runs and pulls hard but had strange starting issues I could never figure out.

I finally solved the problem and it's slightly out there. The rebuilt engine is a 70's Olds 350 with a mild cam. The motor had only 2,500 miles on it when I got it. The PO pointed out he had everything performed by a pro mechanic. Hmmm? Sound familiar? Been there?

I find the "pro" installed fresh HEI components, but perhaps the wrong ones? While researching HEI parts, I stumble upon Olds having a different setup. The distributor pickup coil has a (black) connector that needs to be paired with a White/Red wired coil. Ready? The reason why is the location of the starter and alternator. Chevy's have the alt. on the left and the starter on the right where Olds is backwards. The inductive energy straying from the Alt./Starter locations (when starting the car) may affect the mag pickup signal where the polarity of the coils' primary winding matters. So it seems Chevy's and Olds have different polarity coils. A Chevy HEI pickup has a Yellow connector and pairs with a Yellow/Red Coil. Olds reverses the polarity specifying a White/Red flavor.

The car kept hosing me where it was a bugger to start when hot or from just sitting sometimes. I chased this for months so when I read the symptom of the wrong coil creating hard starting where guys thought it was failing ignition or fuel, I thought I'd give it a go. I had the Chevy (yellow/red) in there. I found a White/Red coil on Summit made by Crane. In fact, several manufacturers offer both versions. I also ordered a fresh Delco D1906 module for a baseline.

My results were excellent. The car has no more strange start-up issues. Runs smooth and idles steady as before. I'm not exactly sure the coil polarity was what made the fix but who knows? There would be great science and voodoo going on here. This is all subjective to many things and I should point out some manufacturers (MSD) claim coil polarity doesn't matter. (maybe 'cause they only offer the Chevy version?) Buy hey, it worked for my "backwards" car. Seriously, the car is healed.

oldcutlass

I never heard of that but...I found an article that explains it. Glad your cars running better.

Reference at the bottom of the page:
http://www.chevelles.com/techref/ftecref5.html

White_Knuckles

Thanks Eric, I finally got a pay-off from Internet non-sense keeping me awake at night. That article is packed full of HEI goodness!

Also in the research, I discovered newer HEI modules don't starve spark at high RPM like the originals. I'm afraid many seek snotty external capacitive discharge boxes and wonder coils they basically don't need. HEI Modules with "extra dwell" or in-cap "higher-voltage", "quick saturation" coils are marketing foo foo. Many circled back to factory spec components which worked best for mild builds.

Oh and use CPU grade thermal paste like Silver 5 not the cheap white goo modules ship with.