MSD Do I keep it

[Mister1500]

Hi all. It's been a minute since i last posted anything. Sorry, life gets in the way sometimes! I just acquired a new to me (my second) 1999 GMC Suburban C1500 SLE w/5.7L under the hood. It is running but needs some trans help (needs a trans swap) I realized after getting it home that it has a MSD ignition system on it. Everything seems to run fine. I am not familiar with this on a first hand basis. I do know they are more so used on street cars and racing applications. Since it seems to be working, do I leave it or should I replaced it back to stock at first chance? I dont need reliability issues and I dont know why it was installed. Any help is greatly appreciated. Thanks!

 

[Drunkcanuk]

Hi all. It's been a minute since i last posted anything. Sorry, life gets in the way sometimes! I just acquired a new to me (my second) 1999 GMC Suburban C1500 SLE w/5.7L under the hood. It is running but needs some trans help (needs a trans swap) I realized after getting it home that it has a MSD ignition system on it. Everything seems to run fine. I am not familiar with this on a first hand basis. I do know they are more so used on street cars and racing applications. Since it seems to be working, do I leave it or should I replaced it back to stock at first chance? I dont need reliability issues and I dont know why it was installed. Any help is greatly appreciated. Thanks!

Maybe post up some pictures or part numbers of what you have.
Is it a full ignition box or just a ignition coil?
A distributor?

 

[Schurkey]

WHICH "MSD ignition system"? They have many different part numbers, including combinations of spark-box, distributor, coil, plug wires, and so forth.

I've run MSD spark boxes, an ancient MSD ignition coil, and their plug wire sets. I've never owned an MSD distributor. Their most-popular ignition coils are high-failure Communist Chinese crap. Their "good" coils are really expensive. I stopped buying the plug wire sets when I figured-out I could get a competing product as a Summit "house brand" for half the dollars. Their spark boxes were novel at one time, but now have competition from numerous companies. I've never really seen an improvement over an HEI on an engine that was actually tuned properly. The MSD spark boxes make the biggest difference on poorly-tuned engines that have significant misfire including due to fueling issues.

Since that's not really a problem on stock or near-stock feedback-fuel-injected engines, an MSD spark-box is unlikely to provide any real benefit.

OTOH, it's not hurting anything, either.

Run it until it dies, but be prepared to change it back to the stock ignition module when it does. I had an MSD 6T on my '88 K1500 for awhile. Died going around an intersection, so I lost the engine power and the power steering. Coasted into a parking lot, returned the vehicle to the stock HEI by swapping a few wires, and was on my way.

 

[Mister1500]

Maybe post up some pictures or part numbers of what you have.
Is it a full ignition box or just a ignition coil?
A distributor?

So I am currently at work, but it appears to be a complete system, It has a MSD controller where the second battery box is located. I beleive it is a 6A or 6AL if memory serves.

 

[Mister1500]

WHICH "MSD ignition system"? They have many different part numbers, including combinations of spark-box, distributor, coil, plug wires, and so forth.

I've run MSD spark boxes, an ancient MSD ignition coil, and their plug wire sets. I've never owned an MSD distributor. Their most-popular ignition coils are high-failure Communist Chinese crap. Their "good" coils are really expensive. I stopped buying the plug wire sets when I figured-out I could get a competing product as a Summit "house brand" for half the dollars. Their spark boxes were novel at one time, but now have competition from numerous companies. I've never really seen an improvement over an HEI on an engine that was actually tuned properly. The MSD spark boxes make the biggest difference on poorly-tuned engines that have significant misfire including due to fueling issues.

Since that's not really a problem on stock or near-stock feedback-fuel-injected engines, an MSD spark-box is unlikely to provide any real benefit.

OTOH, it's not hurting anything, either.

Run it until it dies, but be prepared to change it back to the stock ignition module when it does. I had an MSD 6T on my '88 K1500 for awhile. Died going around an intersection, so I lost the engine power and the power steering. Coasted into a parking lot, returned the vehicle to the stock HEI by swapping a few wires, and was on my way.

Good to know, thanks for the heads up. I couldn't really understand why this was put on this unit, maybe one if the previous was covering something up or maybe towing looking for a little something extra? I see it has a K&N decal on the airbox, I haven't opened it yet and some sort of "performance" exhaust system that I need to try and identify if it is or not. Bottom line, super clean, no body rot or rust anywhere which is almost unheard of in the Midwest. I'll update more once I figure more out. Thanks!!!

 

[Schurkey]

I beleive it is a 6A or 6AL

The old analog boxes? They're my favorites--but they're not perfect. Racers would run two of the MSD boxes, with a switch system so when one failed, the driver could continue with the "spare" box and coil.

The newer "digital" boxes have similar model numbers--Digital 6AL, 6AL-2, Ultra 6AL, Ultra 6AL Plus, Programmable 6AL-2 are some examples.

Listing the part numbers would be best.

 

[Erik the Awful]

If it runs, don't dork with it.

In my opinion, MSD has always been hot garbage - and I have two of their boxes. They make their crap twice as big as they need it to be so it shows off at the car show. We're fifty years past the introduction of the 6A, and they never shrunk the electronics. Now it's "digital", and it's the same f***ing size. On the old 6As, if you wanted a rev limiter, you had to step up to the 6AL and buy individual "modules" for your rev limit. They were simply resistors. Crane's Hi6 ignition box was half the size and came standard with a rev limiter on a rheostat so you could dial in your rev limit.

 

[Mister1500]

So, I have determined it is a 6A. I assume it was just for "show". I assume it is okay to run it until it fails and then just swap it back to stock. Is there any reason I should just yank it out now? At first glance it looks like a stock distributor cap. How can I tell if the distributor is stock or MSD? Thanks for any help and advice!

 

[Schurkey]

Look for an MSD tag on the aluminum distributor.

If the distributor is plastic, it's OEM.

 

[GoToGuy]

Why do you assume anything. As you said previous owner. Did you ask them about it? Before purchase did you look under the hood? Most likely one would purchase the MSD for any improvement in spark efficiency and or if previous distributor died. Why make wild assumptions with no basis ? If it was installed more than 10 years ago , there's a chance it's still better than current imports.
Look at the MSD website .