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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Anyone have any experience with the MSD Super HEI Kit? I want to juice up my stock HEI ignition on my 383, but my HEI distributor is brand new and I'd hate to let it go to waste, so I've been thinking about using the distributor and swapping in the MSD system and the MSD spiral core spark plug wires on it.
For what it's worth, my understanding of the HEI is that it's a totally capable arrangement but what's needed to help at higher RPMs (stated as 5500 RPM) is a module and a coil.
MSD has as good a product as anyone.
The ignition box is never a bad idea although the consensus is the HEI will do the job on it's own with the above improvements.
I have a 6AL box mostly for the rev limiter but that I shift everyday at 6500 (when the car is actually on the road) and have no ignition related issues may say something for having it.
Been looking at ignition wires too.
Thinking the 8.5 mm MSD's. Presently I have the Taylor Spiro-Pro and have no complaints. Just need replacements and looking to change it up.
Thanks for the input Skinny, I think my set up would improve with this kit; especially from the dual spark during low rpms before the engine has warmed up. My combo runs great after shes warmed up, but can be a bear during cold start on a cold morning.
... I think my set up would improve with this kit...
It's never a mistake to improve on the ignition system.
Originally Posted by MSgt Luttrell
...but can be a bear during cold start on a cold morning.
Whether that's ignition related remains to be seen.
Being in a cold weather climate (and have often started my car at -15° C) I've found that one of the biggest influences is ignition timing at idle. With 16° of initial and another 16° of idle vacuum advance, it will idle (at 850), with NO choke, after about 30 seconds of holding the RPMs at 1300-1500. I have no doubt that a solid ignition contributes to that although it seems timing is key.
My initial reply (to the first post) was in reference to your wanting to keep your existing HEI. The general take on it is, yes. Go with it because they work very well. Add the performance bits and you should be good to go.
Hey Skinny, how about a pic of where you mounted your MSD box and coil. I'm about to pull the trigger on it I think.
Here you go.
I bent a sheet of thin aluminium to make a "shelf" for the box to sit on. At the time, it was perched over the charcoal canister in the driver's side front corner. (The charcoal can is long gone now and replaced with the catch can you can see). Dimensions for the platform are approx: 7" high, 9" across (left to right) and 6" front to back. I even manged to use the existing chassis holes and speed nuts to screw the whole thing down. Punched a couple of "speed holes" in it for effect (and access to the hardware).
I like it near the front as I figure it's the coolest place (in terms of temperature not style) to put it. These things don't care all that much for heat.
I'm running a small cap MSD distributor now so the coil is mounted on the firewall above the heater box. The only thing about the HEI I never cared for was it's size. I haven't installed it yet but I'll be using a 18" diameter pan around the carb to serve as part of the cold air package I'm assembling. The diameter of pan takes up space where the HEI would be. There's enough room using a small cap distributor though.
Costs you $135 and should allow you to spin up to 7000RPM without any issue.
Exactly what I was talking about with an upgraded coil and module.
DUI and MSD are on par when it comes to these components. The thing is to make the improvements in the first place.
The ignition box is added insurance and of course the features can be handy too. I live off of the rev limiter.
Hey Skinny, I've got a silly question for you, reading the online instructions for this kit, it mentions something about by passing the in line filter for the stock GM tachometer to work with it? I've never installed one of these kits and would like to keep my stock tach with the install, but have no idea what they are talking about with by passing the in line filter; can you elaborate on this and did you keep your stock tach?
I've a couple of experiences to relate to.
First is the Camaro. That install was straightforward in that I used an aftermarket tach. That meant a simple connection between the tach and the output from the ignition box.
The other is the TA. This was a few years ago however I had to install the MSD tach module for use with the factory gauge. I don't recall which PN it was.
As for the instructions saying to "bypass in-line filter", I'm not entirely certain what they're referring to. My guess is that applies more to later model applications and that you'll probably go the same route as I did with the TA.
EDIT: From accounts posted around the internet, it seems it IS a matter of using the MSD adapter to make a factory tach functional.
For the record, the inline tach filter that has to be bypassed on a gm to run a stock tachometer with the MSD 6AL box is mounted on the intake of cars that came stock with an HEI distributor and is mounted on the back of the engine block on later models that had a computer controlled distributor.
On my '86 IROC Z28, which cam factory with a computer controlled distributor, it's mounted on the back of the block.
Well, there you go. (Thanks for that piece of info)
Now it's a question of whether a module is needed after the filter has been by-passed.
The tech guy at Summit said it will work after the filter is bypassed. I still have an email out to MSD on the same subject, I'll let you know if they say any different than the Summit guys.
I installed the new MSD Digital Ignition System in the IROC today, I first had to build a mount bracket for the Control Box; I installed it in the left front fender area for a little cooler air flow on it. I should add that the tach worked with out doing anything except connecting it to the grey tach wire from the control box.
Do you notice a difference in the cold start performance?
Yes Skinny I did and I haven't even regapped the plugs yet. It sounds different and is peppier than before, my back is bothering me today, so I'll have to wait on regapping the plugs, but I bet it'll run even better then.
Which reminded me to re-visit what I've been doing. I sort of remembered that plug gaps could be opened to .050" and more. Checking the MSD tech forum came up with this in reference to the 6A box:
"The main determining factor for gapping a spark plug is the compression ratio of the motor. Once you have determined this then you can properly gap your plugs. This chart is a good starting point:
COMPRESSION.......PLUG GAP
Up to 10:5:1.........0.040"-0.060"
10.5:1 - 13.0:1.....0.032"-0.040"
Above 13.0:1........0.025"-0.032"
We recommend using a standard copper plug, 1-2 heat ranges cooler than stock OE; we really have no preference for brands. Although we do suggest staying away from any "HYPE", platinum, or iridium type plugs. When you combine them with a CD type ignition, they can cause pre-ignition problems.
MSD Tech Support
915-855-7123"
I've no idea if you've investigated that or not.
I've mine gapped at .050" and there's never been any evidence of distress so that's where I keep them. I've never strayed beyond the recommended heat range , and again with no signs of trouble, I keep what I've got. I think though, that once I really start to beat it up at the track (and that is my intention), I'll need to check on them.
Which reminded me to re-visit what I've been doing. I sort of remembered that plug gaps could be opened to .050" and more. Checking the MSD tech forum came up with this in reference to the 6A box:
"The main determining factor for gapping a spark plug is the compression ratio of the motor. Once you have determined this then you can properly gap your plugs. This chart is a good starting point:
COMPRESSION.......PLUG GAP
Up to 10:5:1.........0.040"-0.060"
10.5:1 - 13.0:1.....0.032"-0.040"
Above 13.0:1........0.025"-0.032"
We recommend using a standard copper plug, 1-2 heat ranges cooler than stock OE; we really have no preference for brands. Although we do suggest staying away from any "HYPE", platinum, or iridium type plugs. When you combine them with a CD type ignition, they can cause pre-ignition problems.
MSD Tech Support
915-855-7123"
I've no idea if you've investigated that or not.
I've mine gapped at .050" and there's never been any evidence of distress so that's where I keep them. I've never strayed beyond the recommended heat range , and again with no signs of trouble, I keep what I've got. I think though, that once I really start to beat it up at the track (and that is my intention), I'll need to check on them.
MSD provided that chart in the instructions, my engine is 10:1 so I plan on gapping them to .050". I've been running my plugs gapped at .035 to combat the cold start issues I was having with the stock HEI. I'm running Champion 792 spark plugs that were recommended by the builders.
02-05-2017, 12:39 PM
