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Hello To All, I Have A 72 Cutlass With A 350 Rebuilt 7 Years ago. At That Time Installed A Mallory Unilite Distributor And MSD 6A Ignition Control. All Was Fine Until A Few Days Ago When The Car Sputter And Died .Able To Get It Home. Started Right Up Ran For About 5 Min Then Again Sputtered And Died , It Did This 3 Times. I Said Hell With It . Next Morning Went Out Started Up And Ran Normal, Took It Out For Drive All Good. Next Day Went Out For A Longer Drive Died On Me Had To Have It Towed. Was Talking To A Few Gear Heads I Know They Had Same Problem With Unilite And Their Modules .Said I Might Want To Look Into A Different Distributor . I Know The Module Is Still Available But I Would Like Some Recommendations On A Distributor That Reliable . Thanks
I installed a GM HEI distributor from a 1977 engine in my car back in the 1980s and it's still working perfectly. I have a replacement module in the glove box "just in case" the original module fails.
Electronic modules do have failure modes that are heat-related, and these are often intermittent failures. You can spend the money and effort to change the distributor, which then will be fine - until it isn't, or you can just replace the module in the current distributor.
Went through the Mallory unilite distributor experiement in the 80’s. Maybe it lasted a year until I had a problem like you describe.
I went back to points, then to GM HEI with a few wiring harness modifications as explained here on C/O. I ran GM HEI from Taylor for many many years. Very reliable but I kept a spare module in the car because they don’t fail elegantly. They just stop dead sometimes. Taylor and the others use the traditional GM weights and springs to control timing advance/retard which always left me with a mild midthrottle knock or I had to dial the timing back so far that the engines would underperform in my view.
About 2 years ago I switched to Progression Ignition Bluetooth controlled HEI’s on both cars. So far, so great. No ping, There’s no advance below 900 rpm so both cars fire up perfectly with no too-much-advance starter strain. The real advantages of these things are that
1) you can build your own timing tables with an app on your phone. And have multiple maps for different kinds of gas. For me this ability has totally eliminated knocks all across the RPM band from idle, to part throttle to WOT. That’s a big leap for me. I got _way_ into springs & vacuum cans before this and could never really get the engines quite right. Progression distributors got me across the performance line.
2) You can shut down the distributor so it won’t fire unless your phone is nearby. Nice anti-theft feature, though I don’t use it much.
3) It’s a driving distraction, but the phone app has a gauge page which shows advance in realtime as the engine is running and the vacuum input so you can improve your maps.
I’m not affiliated with the company, just reporting a couple of years experience. Long term, if they crater (go out of business) you’ll be stuck with no way to update the distributor or get new modules. The app won’t get updated an so on. These are risks I’m running now.
As you can tell, I’m happy to be at this chapter of the journey.
went through the mallory unilite distributor experiement in the 80’s. Maybe it lasted a year until i had a problem like you describe.
I went back to points, then to gm hei with a few wiring harness modifications as explained here on c/o. I ran gm hei from taylor for many many years. Very reliable but i kept a spare module in the car because they don’t fail elegantly. They just stop dead sometimes. Taylor and the others use the traditional gm weights and springs to control timing advance/retard which always left me with a mild midthrottle knock or i had to dial the timing back so far that the engines would underperform in my view.
About 2 years ago i switched to progression ignition bluetooth controlled hei’s on both cars. So far, so great. No ping, there’s no advance below 900 rpm so both cars fire up perfectly with no too-much-advance starter strain. The real advantages of these things are that
1) you can build your own timing tables with an app on your phone. And have multiple maps for different kinds of gas. For me this ability has totally eliminated knocks all across the rpm band from idle, to part throttle to wot. That’s a big leap for me. I got _way_ into springs & vacuum cans before this and could never really get the engines quite right. Progression distributors got me across the performance line.
2) you can shut down the distributor so it won’t fire unless your phone is nearby. Nice anti-theft feature, though i don’t use it much.
3) it’s a driving distraction, but the phone app has a gauge page which shows advance in realtime as the engine is running and the vacuum input so you can improve your maps.
I’m not affiliated with the company, just reporting a couple of years experience. Long term, if they crater (go out of business) you’ll be stuck with no way to update the distributor or get new modules. The app won’t get updated an so on. These are risks i’m running now.
As you can tell, i’m happy to be at this chapter of the journey.
GROUNDS!
You guys... these cars are 50-60 ± years old. The grounds started deteriorating days/months after they rolled off the assemble line.
Go through the car and do some cleaning.
Bad grounds = fried modules.
The Mallory and other ignition systems need good clean grounds. So do the rest of the cars systems.
My friends 55 SBC did this same thing. We replaced the Unilite module, cleaned the grounds, and ran a dedicated strap from the engine to the frame, to the engine and firewall and cleaned the battery to engine block neg wire. Did this 15 years ago and its still running strong. Probably time to re-clean them.
