HEI and MSD box [Archive] - Chevelle Tech

: HEI and MSD box


Malibu ss 64
Jun 28th, 09, 4:20 AM
Took my car for a little longer drive than I ever did before the trip was 150-200 miles. Worked fine almost all way like 1 mile from home it died and refused to restart.

Installed MSD 6421 box earlier this year for revlimiter. Know that with a HEI with coil in cap you can get problems with burned coils so I removed the coil(accel supercoil) wich was pretty hot replaced the cap, bushing and coil(used gm) and it fired up droved it home but when I should park it the car died again removed the coil again the bushing and cap had melted. So replaced cap, bushing, coil(new gm) and rotor and was able to park the car.

Can the accel coil be so much better that it will live longer then a gm coil? My guess is something went wrong with the first change I did it was dark and all light I had was from a mag lite.

Can I damaged the box?

Going to try to cure the problem with one of this solutions.

Change to a modified dust cover http://www.msdignition.com/product.aspx?id=5417&terms=8401 and external coil http://www.msdignition.com/product.aspx?id=5011&terms=8207

or change out distributor to a http://www.msdignition.com/product.aspx?id=5353&terms=8361 and same coil as above.

The first solution is cheaper+I did spend quite some time to get my mech advance to work for my aplication. Can you reduce the mech advance to 11 degrees in the msd distribuor like my HEI has?
Im not sure if the MSD vac can will work with lower vacuum my engine has?

Will both solutions work or will one be better? Dont want more burned coils is there any chanses I will burn the modified dustcover instead? or the external coil?

Since my cam has cast gear I want to run a gm distrubor gear is the MSD shaft bigger in diameter so the gear need so be honed to fit if I chose that solution?

ovelle
Jun 28th, 09, 8:57 AM
go with the msd pro billet and never look back!!!hafta change wires to and i prefer a jacobs
coil myself..but pro billet distr,msd 6a,8.8 wires,jacobs coil (or preference) and youll have one of the best reliable ignitions money can buy...if me i would also do away with vacuum advance and strictly mechanical.unless your looking to save mph with your 570 horse big block LOL

fridgeguy
Jun 28th, 09, 9:21 AM
The real simple solution is to install MSD's low resistance HEI bushing, pn 8412. This will more than liking stop the problem you are experiencing. Having said that the REAL solution is the probillet distributor and HVC coil. I just installed them along with an MSD 6AL box it's really the only way to go. Very easy installation. It comes with several advance bushings all you have to do is pick the advance you want and away you go. I got the vacumm advance Probillet but am runing without it.

ratengine
Jun 28th, 09, 9:25 AM
You need to pull out the stock carbon rotor brush. It has very high resistance and will burn and melt cap where it goes thru to rotor. Get yourself a HEI Copper brush from MSD see link. I would Keep the HEI if its not worn and also get the MSD HEI cap that you can run a external coil.


Here is the brush
http://www.jegs.com/i/MSD/121/8412/10002/-1

Here is the coil cover you need
http://www.jegs.com/i/MSD/121/8401/10002/-1

They both work for me, as I had the same troubles with melting cap using a MSD with HEI.
Good luck

Malibu ss 64
Jun 28th, 09, 10:49 AM
You need to pull out the stock carbon rotor brush. It has very high resistance and will burn and melt cap where it goes thru to rotor. Get yourself a HEI Copper brush from MSD see link. I would Keep the HEI if its not worn and also get the MSD HEI cap that you can run a external coil.


Here is the brush
http://www.jegs.com/i/MSD/121/8412/10002/-1

Here is the coil cover you need
http://www.jegs.com/i/MSD/121/8401/10002/-1

They both work for me, as I had the same troubles with melting cap using a MSD with HEI.
Good luck

Thanks, what coil did you use?

Marcus

Malibu ss 64
Jun 28th, 09, 10:54 AM
go with the msd pro billet and never look back!!!hafta change wires to and i prefer a jacobs
coil myself..but pro billet distr,msd 6a,8.8 wires,jacobs coil (or preference) and youll have one of the best reliable ignitions money can buy...if me i would also do away with vacuum advance and strictly mechanical.unless your looking to save mph with your 570 horse big block LOL

Think its qiute economical around 12 miles/galon LOL

Marcus

trmnatr
Jun 28th, 09, 3:01 PM
most single four barrel applications i use a HEI all the time when its a high rpm application

I have an HEI i run 8200rpm with zero issues but i start with a GM HEI not some cheap china made $25 distributer

I install a mechanical and vacuum advance lockout plate, you can put a curve kit in it and adjustable vacuum advance is you desire

Use the MSD HEI cover that allows an external coil, use Standard Ignition cap and rotor, i prefer the Standard Blue Streak performance kit, excellent quality and cheaper than MSD/Accel etc

Then i install the box, i dont like MSD but have used them. I use ALL Crane Cams ignition box, coils and plug wires. On my car, 9 years thus far with the box under the hood on top of the ac/heater box with zero failures. The rev limiter is built in so no chips needed through 9900rpm

I like the HEI cap due to the terminals being spaced out to help prevent cross firing at higher rpm levels (above 6,000rpm)

Also just a side note,,, A customer wanted me to install Pertronix HEI kit, We have used the points to electronic conversion with excellent results. I told him i dont know about using an HEI cap, rotor, coil, module, bushing, coil cover, adjustable vacuum advance for $150 - I told him you want it you buy it. This is for a high compression street engine running leaded fuel and im here to say it burns the fuel and has been flawless and only cost $150

Sure you have to be able to rebuild the distributer but most here can. Below is a link to the HEI kit for anybody considering a great street setup without a box

http://www.jegs.com/i/Pertronix/751/D8000/10002/-1#

EDIT: in the above link they have come down from $150 to $119.99

Malibu ss 64
Jul 10th, 09, 12:32 PM
Started to install the new cap, low resistance bushing, external coil and modified dust cover. Shall I leave or remove the rubber gasket that sat under the in cap coil?

Marcus

66 BRONZE
Jul 10th, 09, 3:36 PM
I have run the MSD6 series in every street car I have ever owned. Their directions that come with the CD box clearly states you have to use an MSD low resistance HEI bushing. I have had ZERO issues running this set-up WITHOUT an external coil.

SS402
Jul 10th, 09, 4:04 PM
Is the HEI being supplied with a 12 signal, it kinda sounds like a resistive circuit (less than 12V) is bing supplied, in which case the current draw (heat) would be higher,, E = I x R
Current is inversely proportional to Voltage, if R stays the same and V is reduced then I is increased

Dave427
Jul 10th, 09, 4:36 PM
Yes use the rubber gasket or boot.

Dave