Recuring ignition miss

[Rick Parker]

This is a little long .....sorry

I have a problem that I really haven't solved but have circumvented(?)
3 years ago when I got my car back on the road after a long rebuild I installed fresh set of fine wire Champion race plugs. I had used this same plug # previously with good results. I use a MSD-6 Box, Pro Billet small Diameter Distributor and new solid core wires (more on this later). To my surprise it would not rev past about 5200. It was suggested I change to MSD type resistance wires but the results were unchanged. So then I bought some Autolite Race plugs with cut back electrodes, no change. HMMM So I put the "New" solid core wires back on and checked the plugs but again the results were the same. In a last ditch effort I changed the plugs to a set of resistor type that had and BAM.... 7000 No problem. I changed the wires to the resistance ones and 7000 rpm no problem. Changed back to the Champion Race or Autolite Race plugs and 5200 max. I was not able to cure it. I gave in and to this day use the resistor plugs and the tan Solid Core Wires which I had desperately hunted for while doing the rebuild.
Before the rebuild I have always used solid core wires (I'm old school), the ones before the rebuild were Black Mallory copper jacketed solid core wires. During the rebuild I completely rewired the car. Aside from this issue everything electrical has operated without any problems.
Today I called MSD to discuss this and their suggestion was to check the grounds between the heads and the block; block and chassis. He asked where the battery was located and how it was grounded and went on to say that often grounding at the rear of the chassis with a short cable is not always sufficient. He explained that the welds throughout the chassis between the battery connection at the rear and the ground connection to the block at the front can have some resistance that will affect the ignition operation. (??) He said the bolts/studs that secure the heads to the block are a poor conductor and since the body of the spark plug is grounded by being threaded into the cylinder head the head would need to be properly grounded itself by a ground cable to the block. I had never given this a second thought beliveing the studs were sufficient. So...the jury is out.
I guess I will check the grounds from the heads to the block/chassis.
Have any of you guys ever experience anything similar to this. I realize they reccomend resistance wires but in my application they did nothing. Not until the resistance plugs were installed did the engine wake up. What do you think? The fact that it runs well with one plug and not the other is what baffles me, how would bad grounds affect one and not the other?
BTW...good news for some of us. They indicated they will be begin producing a couple of their distributor caps in Black. Primarily based on anticipated demand. Initially the large diameter Ford cap and an application for Chevrolet. I would like to see the small Diameter Ford cap done too. Specifically their part #8431 which covers 4 Ford Distributor applications for their Small Diameter Billet Distributors. Maybe if we scream loud enough it will help.