Alternate Cap for Early '80s HEI

Is there a no-coil cap available for the early '80s Chevy HEI distributor? It normally has the coil on the cap.

 

Mallory sells and adapter and Taylor sells this http://www.taylorvertex.com/Products/index.cgi/productListing?id=219904

http://www.summitracing.com/parts/tay-918132/media/images

You are going to have to come up with a coil that puts out more than 40,000 volts though. A stock point type coil doesn't have enough poop to work with an HEI.

 

Thanks, Mr48chev.

 

That cap is NOT for an early '80s HEI. It is for a 1987-up, TBI or TPI HEI setup. That particular distributor has no advance weights, or vacuum advance, just a trigger for the ignition.

 

I'd have never thought about that being an issue, thinking that the module and pole piece are acting as the switch for the primary current. Unless your engine requires 40kv on the secondary side to fire off the cylinder.

Somebody get GMC Bubba in here to educate me!

 

WOW, sometimes these threads get pretty wacked out!

First of all any 12 volt coil will work out very well with the hei ignition and control module etc.
However if you want the hei to supply the voltage it's designed to do it needs a .5 ohm coil primary. It's all about current actually and a .5 ohm coil will drive the module to it's 5.5 amp limit very quickly. The dwell time for coil saturation is variable based on rpm being low at idle and higher when the throttle is opened up.
No car should ever need 40,000 volts on a constant basis and ignition parts won't stand up to that level of performance for very long. The hei was created to satisfy a EPA mandate of certifying the ignition could maintain correct emissions for 50,000 miles and if you remember GM had a terrible time making it last. Wider distributor cap positioning was required to prevent cross firing with the added voltage of the wider plugs gaps required by leaner air fuel mixtures!
I have customers looking for small cap heis quite often especially the flathead guys. A small cap just won't let me run the heis higher voltages and we don't need the wider gaps on most engines.
A couple of facts:
A gasoline engine will only use what voltage it needs to light the air fuel mixture. A 40,000 volt coil will only use approx 5-8,000 volts on a properly tuned engine....
Every system has , voltage available (the voltage design of the coil), voltage required (the voltage needed to ignite the hydrocarbon fuel mixture),and voltage reserve ( the difference in the available and required voltage)..

Rich air fuel requires less voltage and lean air fuel requires more.

Hope this helps, ask away...

 

still don't see an answer to the question asked

 

No cap for the early hei's is available, what most use due to the larger diameter is remove the coil and different aftermarket folks have made a in. Cap adapter to use a remote mounted ignition coil. I can send ya one as I have a couple used ones laying around, be glad to help.

 

Sorry , got it in the post above, I felt everyone should have a understanding of why the large cap was used to start with...

 

Thanks, Bubba!

It is great to have folks like you on here to help us troglodytes out!

 

thank you Bubba for the answer

 

I love the Bubba, I'm gonna have his baby one day......well, ok, I wont go that far but he does awesome distributor work and makes a wicked hot sauce too!

 

Or you can do something like this.