Cap and rotor recommendation for L98

[TedC]

The stock black AC Delco cap uses aluminum terminals. From what I've been reading copper or brass terminals are better, especially those that are molded in and not press fitted. On my 1989, the cap screws into the base, and does not use the more common cap that clamps down (L shaped ends vs. threads). The MSD 8416 and Accel 8122 look like better replacements but they are clamp mounted and not screw mounted. I read a post here at CAC that someone had installed the MSD 8416 by replacing the screws. Is there really a benefit of brass terminals over aluminum, and if so which cap and rotor do you recommend?

Added...
I just found an Accel 8131 on the internet. "High performance 60kV-rated tan alkyd molding compound (mineral filled polyester) is used for superior protection from “arc-thru” and crossfire. Compression molded caps are stress-relieved immediately after molding in special fixtures to ensure dimensional stability. High conductivity, corrosion resistant brass or copper inserts and stainless steel rotor springs provide unrestricted spark energy flow. This is only for electronically controlled HEI's such as the Large-Cap HEI's found in TPI Corvettes and some Camaros."

 

[boomdriver]

I just bought and installed all this stuff. I was a little surprized at the cap differences...
The top of the line with brass was abolutely useless because the bottom edge was malformed enough to be a very poor fit with the aligning marks or tabs that were molded in. That was the brass cap. My old brass cap also had loose terminals that would twist around.I could easily see the odd patterns of scorching inside.

The stores next grade cap was aluminum post but it fit like a glove. Both were screw type. The aluminum cap was close to $10 cheaper but it fit perfectly.

The material used to conduct (brass or alum) is not as important as the cleanliness of the connections. With aluminum, oxidation is more likely so a good die-electric grease should be used to seal out moisture and lubricate the boots. The cap fit is very important because it CAN pinch the module wires inside and the fit on the dist base makes an even rotation of the rotor against the caps terminals inside.

 

[TedC]

Accel part # 8131 is the right cap and rotor kit for the TPI, and part # 8343 if you want matching coil cover in wonderful accel brown. Accel introduced blue and red colors for the more common clamp down V8 caps. I just ordered the 8131 and will give it a try.

 

[TedC]

New Accel cap and rotor are in. The old AC Delco parts were installed by me 3 years and 7000 miles ago when I first purchased this vette. Found carbon dust on the rotor near the stainless steal spring. Surprised how much carbon had collected. Also, inside the cap, each terminal had crusted on white residue from the high voltage arching. The AC cap appears to use zinc coated steel terminals, not aluminum. I suspect the new cap and rotor will end up the same way in 3 years, even with the solid brass terminals.

 

[MBDiagMan]

Actually a good bit of carbon dust is tolerated inside the cap. As long as there is not serious resistance at the rotor to center post connection and no cracks, there will be no spark scatter or power drained to ground.

All that said, replacing cap and rotor too often is certainly a better plan than neglecting it until failure.