When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I am wondering about which type of distributor cap is best. By that I don't meen the brand but the contact material . Aluminum or Brass? I believe Aluminum is a better conductor but some people appear to want to stay away from that type of cap. What is the reason for wanting Brass over Aluminum or vise versa? Thanks and take care.
Aluminum is better than brass as a conductor. However, aluminum oxidizes which can form a layer that can hinder its ability for good conductivity. Brass does not oxidize so it makes it better mechanically but it is less conductive.
Copper is best!
A distributor cap is prone to condensation which promotes oxidation. Vented distributor cap to help with condensation with brass.
Hello,
Also, a 'bakelite' cap while typically more costly is generally considered to be superior to a plastic cap.
Although bakelite is a type of plastic.
Regards....
Tend to agree that the Aluminium contact caps have issues with the contacts eroding away far to quickly. They tend to be less expensive however.
Just not that expensive for a quality cap however. Maybe not the best place to save a buck.
Venting cap & base of dist is very helpful to good performance & reliability. The shower of sparks within dist ionizes the humid air; creating a corrosive environment which becomes more prone to crossfire-misfire.
Marine-grade caps often have a vent like shown in pic in P#2. The dist in final sbc gen 1 iteration (L31 & L30) have dist with small vertical hole in base (for ventilation) but they become clogged and then dist goes to hell.
Ventilate it and keep it free-flowing and that's half the battle. FWIW, Gen II (LT1 & LT4) sbc had lotsa dist problems; many were solved by venting and even had a tube attached to intake that pulled a vacuum thru dist body.
Last edited by Rebelyell; Nov 10, 2025 at 11:52 PM.
Distributor Caps
