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Fairly irrelevant comparison....NASCAR to street car. That being said, with all of the money circulating in NASCAR, if the MSD boxes were so failure prone, why wouldn't they use something else?
what else is on the market to compete. I truly don't know
But are they all basically just the same thing? I am not trying to start anything. Does one offer something the others don't. Or is just one marketed better so that is what everyone buys?
On the other hand of the boxes were not prone to failure in a measly 500 miles why would Nascar guys feel the need to run 2 boxes. Hmmmm.
Well that's an easy one. The cost of a second box they may or may not need is minuscule compared to the cost of not winning or even not finishing a race.
St. Jude Donor '04-'05-'06-'07-'08-'09-'10, '14-'15
Originally Posted by jim lockwood
Well that's an easy one. The cost of a second box they may or may not need is minuscule compared to the cost of not winning or even not finishing a race.
Exactly my point. As a racer.... you know it's always good to have a Back up.
Finally found a problem that may have caused the MSD to fail, but first, a word of advice: - Start at the bottom and move up. Of course I went the other way.
Rechecked the fuel system and all seems good with 7 psi of fuel pressure when cranking.
I though maybe the cheap rocker switch I used for a kill switch was the problem as it had no spark at the coil. After tearing the interior apart to test the switch and wiring to the firewall connector, I ruled it out.
Checked the voltages before removing the box, and then the resistance of the wiring on the firewall. Voltages seemed low and resistance high. Took the wiring loom apart looking for hot wires or etc. Resistance on the yellow wire to the coil from the starter was very high. Next was the removal of the MSD box and bench tested it. Confirmed it was dead, but what caused it to die?
Finally went where I should have gone first, the starter wiring. I noticed a bundle of tape on the loom to the starter S and R posts was brittle and crumbled when I grabbed it, although it was not touching the exhaust manifold.
Removed the loom and the crystallized tape the PO had put on it. Both the yellow and purple wires had been BUBBA spliced wrapping them together. It appeared they had been hot, almost melted the copper. I ran new wires (solder splices and heat shrink) to the solenoid and rewired everything from the fuse box connectors for a Chrysler box adding a couple of inline fuses as I wanted to maintain the reluctor pickup. I have 2 or 3 Chrysler boxes left from my drag racing days, so I checked them and was amazed they all checked good.
I am theorizing the two wires were arcing to each other and possible to the exhaust manifold and thus the short overloaded the MSD box. Maybe the Double E members can confirm my assumption.
My soldering skills are severely challenged due to my hands shaking, good for making mix drinks without a blender and following schematics is not as easy as it used to be 10 years ago, thus the long duration of the repairs. I assembled a kit with a good amplifier, resistor, coil, and pickup for emergency repairs. Will also take a VOM meter and fuel pressure gauge with 2' of hose. Probably won't every need it, but better than the flat bed shame.
The engine fired up on the first try after I remembered to flip the kill switch. Test drive tomorrow, so fingers are crossed.
Thanks for the help from everyone. No final celebration until tomorrow.
NASCAR cars uses two boxes inside the car. They have little faith one will make it 500 miles so they have a back up
Originally Posted by Vega$Vette
On the other hand of the boxes were not prone to failure in a measly 500 miles why would Nascar guys feel the need to run 2 boxes. Hmmmm.
Originally Posted by jim lockwood
Well that's an easy one. The cost of a second box they may or may not need is minuscule compared to the cost of not winning or even not finishing a race.
We always ran two MSD boxes on the Trans Am cars I crewed on in the 80's, and our races were only about an hour or so long and 100 miles. Over the nine or ten years I worked for that team we had a couple fail. They were mounted inside the car on the right side of what there was of a dash, where we could get to them easily to change chips. When racing the interior temps were easily over 100 degrees and there was very little airflow inside the car, but I doubt it was ever hot enough to cause them to fail.
Originally Posted by Viet Nam Vett
Exactly my point. As a racer.... you know it's always good to have a Back up.
While having a back up is nice, weight is the enemy of a race car. The last thing you want is unnecessary extra weight. An extra MSD box may not weigh much, but it all adds up.
As far as electronic ignition street conversions go, I've always liked the Mallory Unilite myself, but I've seen them fail too.
R66, glad you found the problem. Never a pleasant experience being stranded and having to call a stretcher…
I’d like to offer my positive experience w/ using MSD products over the years. I’ve run an MSD 6AL ignition box, MSD billet tach drive distributor and MSD Blaster 2 coil for over 25 years with only 1 ignition problem in that period. Last year I had a frustrating intermittent cut-out while driving that was resolved by switching coils – even though the coil tested good. Turns out I had inadvertently pulled the conductive sleeve connector inside the coil socket at some point when removing the ignition plug. The only electrical connection was made to a screw head at the very bottom of the coil socket. Pictures aren’t great but illustrates the issue. Black (painted) is coil missing the sleeve.
Box is mounted near the battery, inside the passenger side front fender – a discreet location that gets some airflow and protects the unit from exposure to direct exhaust heat.
The 8572 can also drive the factory TI amp. By moving 2 connections up front, I can quickly select either one. The MSD config has better idle, and seems more responsive.
St. Jude Donor '04-'05-'06-'07-'08-'09-'10, '14-'15
As far as electronic ignition street conversions go, I've always liked the Mallory Unilite myself, but I've seen them fail too.
Had one in old ride to work car. 1972 Ford LTD II. One night in the winter @ 17* outside cruising down the Black Horse pike at 55 MPH the motor shut off. No heat stuck on the side of the road. Took AAA 1.5 hours to get to me. The L.E.D. inside the Unilite Decided it was bedtime at went out. End of story. No Ignition. That's when I change to MSD products.
The forensic investigation of the MSD 6A box failure is apparent in the photo below. I shouldn't complain after 30 years of service from the box. I am aware the electronic devices fail catastrophically and instantly leaving the vehicle beside the road. Electronic devices require a stable electrical source and are not tolerant of under or over voltages nor spikes. It is given that the electronic ignitions provide stronger spark to the plugs and thus a better ignition of the fuel. Unless you carry a full complement of electrical troubleshooting devices as well as spare electrical components, I believe it is rare to be able to repair the ignition system on the side of the road.
The points system also can fail instantly, generally the capacitor, but generally provides warning thru poor engine performance prior to leaving you beside the road. The diagnosis and repairs can easily be performed with a few simple tools even on the side of the road. Of course the maintenance of the system must be performed frequently, about every 10,000 miles, to maintain dependable performance of the ignition system.
I do like the better starting and performance of an electronic ignition, but don't like the catastrophic "flat bed failure" which is very common with the newer cars. I am replacing the MSD unit with a Chrysler box as they have a reputation of years of reliability and parts are readily available at the local parts store. However, I am also carrying an extra box as well as a points / condenser set and wire for a road side swap. Being an extremely impatient individual, I don't love waiting 1-1/2 hours for the hook, nor trusting an unknown 'local' mechanic to troubleshoot and repair the old 'relic'.
MSD 6A failure, I believe caused by voltage variant of burnt starter wiring. Considered repair, but the power transistors and other devices are at the end of their life expectancy. Mallory Uni-Lite module melted due to engine compartment heat in a V-8 Vega. Just for information. The module still works, but I don't care to trust it.
How did you get that pic? I believe my MSD 6A may have just failed after a severe pothole incident. I pulled the box out to examine it and it appears to be sealed with no way to get inside. FWIW mine is vintage 1995 and has performed flawlessly until now.
I cut the back cover off of the box to access the internals after I performed the testing and found it was dead. I think I posted the link for the testing on your post about your pothole problem.
I didn't address what in the car could have caused it to fail. There is not much beyond the coil. Excessive primary current from a shorted coil or the wrong coil could do that. Starving it for voltage might do that too. However not much else would. If it worked for a long time and failed suddenly, well that is what electronics often do. I would worry less about something that "took it out." I've been reading about MSD box failures for as long as I've been around.
Here are some photos of MSD innards. What could go wrong here?
OR
Dan
Once I receive my Ph.D. from MIT in electrical engineering, I might give that MSD box a diagnostic whirl............
05-26-2023, 10:19 AM
