MSD Ignition Advice

[Buckskin7T7V]

I have a 77 vette with a (HEI) MSD 6A Capacitive Discharge unit. I was considering installing the MSD 8525 coil. Will this addition increase the performance over the stock coil in the igintion system. I was hoping someone out there has had experience with this set-up and can give advice before I spend the $$$$$.
Thanks

 

[Buckskin7T7V]

Well I did not get any in-put from anyone, so I purchased the MSD 8525 HEI coil and dropped it in. Much, much better than the stock coil. Start-up is quicker and the motor seems to have smooth-out through the whole rpm range.

 

[vmrod]

Did the MSD alone make a difference?

I've got a high output coil and ignition module in the distrib. and was wondering if it was worth the trouble to install one.

 

[Buckskin7T7V]

I installed the 6A MSD box and with this box, you remove the stock or any other module you might be using. The tach plugs into the box and there was a improvment over the Accell coil and modual I was using. I mounted the box on the far. far side of the brake-booster. (1977) When I called Summit the tech suggested that I just use the MSD coil, but to let the box (6A) contol the firing of the plugs and to not use any module at all. It is working great for me.

 

[vmrod]

Let me see if I understand...

When I install an MSD-6A, I will need to remove the ignition module inside the distributor. (The MSD-6A becomes the module.)

Can I still use the coil within the distributor? Or do I need to get an external one?

thanks.

 

[Bob Chadwick]

MSD has it's own pickup that works with the box. You have to remove the existing one inside the distributor.

The existing coil in the cap works fine.

 

[Buckskin7T7V]

Bob is right, I just replaced the coil I was using with the MSD 8525 coil which is a higher output (50,000 volt) coil. It still goes under the cap. No Module at all. This reminds me, that I also used the MSD HEI cap. It comes with a standard bushing and a bronze bushing. The tech at Summit told me to use the bronze one with the 6A box. The standard center bushing would not be able to take the voltage. So I guess you had better purchase the MSD cap when you order the MSD box or at least purchase the bronze center bushing to replace the on in the stock HEI cap you are using now.

 

[AdvancedAutoCC]

You use the mag pickup harness (green and purple wires - included with the 6A box) to bypass the OEM module. You do not have to remove it if you don't want to. MSD's installation instructions give clear directions on how to do this.

 

[Scott Winebarger]

Let me see if I understand...

When I install an MSD-6A, I will need to remove the ignition module inside the distributor. (The MSD-6A becomes the module.)

Can I still use the coil within the distributor? Or do I need to get an external one?

thanks.

I would recommend a new coil .. MSD Multiple Spark Discharge ... the coil will have to be capable of saturating and firing multiple times, your old coil could be getting tired and not up to the challenge. No point in MSD if you are sending half a spark.

 

[Jack]

The tech at Summit told me to use the bronze one with the 6A box. The standard center bushing would not be able to take the voltage. So I guess you had better purchase the MSD cap when you order the MSD box or at least purchase the bronze center bushing to replace the on in the stock HEI cap you are using now.

BS ... that summit tech is FOS (what else is new?) ... For 3 years I've run non-MSD hi-grade parts store HEI caps with carbon button ... bypassed module ... running MSD 6TN ... in a circle track car.

You probably need the upgrade button w/ 7 or higher series box ... I don't think it's needed w/ 6 series ... I don't need it ... have never melted/burned a cap. Several other guys around here are also running a bypassed HEI w/ msd 6 & stock cap ... no problem.