MSD Ignition

[Six_Shooter]

I've installed many MSD boxes on cars using stock ignition components, I can't recall one premature failure of any part. I had a 6AL installed on my Sunbird and Skyhawk for about 2 years before I did an engine swap to an engine with DIS, never experienced any premature failure of ignition components.About your experiance, the first thing that comes to mind is poor grounding of the coil, the next thing is something wrong with the components used. Many people, myself included have used MSD boxes on in cap HEI coils without issue.

[1project2many]

FWIW I've badged MSD as Must Soon Die. The race grade products are worth owning and there are systems built in the '70s and '80s that are still working fine today. But the consumer grade products are completely hit or miss, and when they're a miss they're a big miss. I've been left stranded in 3 of my own cars due to failures in an MSD ignition system over the years and I've diagnosed issues ranging from misfiring cylinders to poor quality REF signals to misinterpreted timing signals and random stalling back to consumer grade boxes.

Large cap HEI in stock form will spark across a .100" plug gap with plenty of energy. Stock DIS systems in good shape can easily throw spark across .500" gaps. Unless you're running in an RPM range where the stock ignition system is having trouble or you have a specific set of conditions that are causing the stock system to perform insufficiently, I personally see no need to spend extra money on an MSD. If anything I'd get an improved aftermarket module and adjust the computer controlled dwell period in the stock calibration for slightly longer spark.

More sparks in a given time frame can definitely cause more frequent parts failure. LT1 owners are probably familiar with GM's Optispark vent campaign in the early cars. Ozone created when sparks occur plus moisture in the cap would react and create nitric acid which would quickly degrade the rotor, cap, and even the distributor itself. The positive ventilation installed in the Opti ensured no buildup of ozone or nitric acid. I've used that same thinking plenty of times on standard distributors. Small cap HEI distributor rotors often get "stuck" to the shaft due to rust and I've seen the insides of the distributor full of corrosion from the terminals in the cap while the end of the rotor just sort of dissolves. In my '57 I cut the end off an old carburetor dashpot with a .020" orifice and installed it in the small cap dizzy. I connected the other end to ported vacuum so air would only draw through when the throttle is open. That was in '93. I have never changed the cap or rotor and they are still in great shape today. In our 5.7 Vortec vans we have problems with moisture buildup in the cap after a large rainstorm or on days with high relative humidity and large temperature swings. It's so bad it can actually cause a no start. In the 20 or so repeat offenders that I've installed positive ventilation the moisture problems are completely gone, and we've moved from changing the cap/rotor at 40-60k mile increments to changing it at 100k mile increments (or when the dang plastic body fails). When using a multiple spark or high voltage spark ignition in a street distributor I would definitely consider a similar modification. The more sparks occur, the more ozone is present, and the greater the potential for acid formation.


Wasn't there an LT1 manifold swap somewhere in this thread?? :)
EDIT: EagleMark Thread Split

[EagleMark]

So that's what that green corroision is?

FWIW the LT1 vent system is sold new still for like $56. It consists of vacuum line, an elbow to intake, a filter that looks like a one way valve (haven't tested if it is) on intake side to engine and I think... something else on intake to distributor... have to look later. I may do this upgrade on my Suburban as it was greenish inside last cap and rotor change about 4 years ago...

[Nasty-Z]

I had a 6AL installed on my Sunbird

Funny you should mention that , I had a 6AL box on my daily driver Sunbird years ago also , simply because I could .....

I will join the no problems club here , MSD ignition boxes , distributors , and electronics since I was old enough to buy them , I have never had a failure , or have experienced premature failure of any quality component.

TOM

[PJG1173]

I run crane HI6 products in my two projects. haven't had any issues which I attribute to they are full digital unlike the MSD unit. I really didn't see any improvement by installing them though. I use them mainly for rev limiters since I would rather cut spark than fuel.

[JeepsAndGuns]

Ya know, after watching that vid mark posted about the optispark, and reading this, I am almost tempted to add a vaccume line ent to the distributor cap on my wrangler. I have a aftermarket coil on it and use the BWD brass terminal cap/rotor, and every time I change it, there is always this thick golden brown film on the inside of the cap. I'm about due for a change, I might try this. Anyone know of a orifice I could install in a vac line? I doubt I need a full open vac line, probably too much of a vac leak.

[93V8S10]

No problem here with the ignition boxes, but I will never own another MSD distributor. Lots of moisture and corrosion, went to start it one rainy day and the darn thing jumped spark so bad that the engine kicked back so hard that it broke the starter drive.

[1project2many]

Anyone know of a orifice I could install in a vac line? I doubt I need a full open vac line, probably too much of a vac leak.

What I've been doing lately is using a 90 degree elbow for 1/8" vacuum / washer hose. I put a paper clip or small wire in one end, mix up a little epoxy and fill the fitting around the wire, and as the epoxy is hardening I pull wire out. Give a .020" - .040" orifice.

[gregs78cam]

I was thinking about putting a fitting in base of the distributor, run a small hose to a check valve and then over to the valve cover opposite the PCV. So that all air that gets sucked into the crankcase comes from the distributor cap. Any problems with this thought?

[EagleMark]

that's not going to be near enough air on it's own...

[JeepsAndGuns]

What I've been doing lately is using a 90 degree elbow for 1/8" vacuum / washer hose. I put a paper clip or small wire in one end, mix up a little epoxy and fill the fitting around the wire, and as the epoxy is hardening I pull wire out. Give a .020" - .040" orifice.

That sounds like a good idea, I may just give that a try!