High Voltage Spark

[Bagoftrix]

Just got my 1990 C4 back from dyno and its kicking out 314 horsepower to the rear tires. Problem I'm having is that the mechanic picked up on is a slight miss. The engine has low miles on it for its age (43 thousand) and still has its original cap and rotor. I'm thinking this could be where the miss is coming from. Question is should I change the cap and rotor out with stock parts, or would it benifit me to go with a performance high voltage performance cap and rotor. Thanks for all your help...

 

[dougelam]

I doubt that's the problem but a good place to start.
There is no such thing as a "high voltage cap and rotor" per say because all ignition systems are considered high voltage.
The differences are in the material the they are made from.
The OEM rotor is glass impregnated to resist the voltage from burning thru to it's mounting.

So

OEM is fine and higher grade aftermarkets are better, they look great also!
Don't forget to transfer the ground strap that's under the coil

And

" DO NOT OVER TIGHTEN THE COIL BOLTS"

That causes the cap to Crack and gives the voltage a place to arc to which in turn creates a missfire

Sent from my SM-T530NU using Tapatalk

 

[kpic]

After I sold my 69 for a Z-28's back seat for my daughter, I bought a Jacobs Ignition. In his book, Dr. Jacobs stated the GM HEI coil in cap was the only OE ignition that could keep up with his ignition module.
Back in the day, Jacobs made good stuff; their nitrous box was excellent.

As times have changed a lot since the 1980s; With proper components (i.e. Accel's low ohm buttons; a coil from elsewhere) the GM OE HEI is still quite a good ignition.

 

[DonB]

The OEM GM AC/Delco is very good quality and will work just fine. They work great on my mildly modified '90 C4. I once used a cheap rotor because I couldn't readily get a Delco and within a couple weeks the engine developed a slight miss. I opened up the cap and found the spark had burned through the cheap plastic rotor and slung plastic particles all around the cap.

Long story short. Pay the extra $$$ and get Delco Professional Rotor # 19106651 and cap #19110932.

Standard Motor Products also make quality replacement ignition components if you can't get AC/Delco. Rock Auto has reasonable prices if you can't get them locally. Plus if you haven't done so yet, get a K & N air filter. Worth every penny.

Now that I helped you open your wallet,....Good Luck!