[Key Largo Realtor]

Anybody using the Mallory Unilite? Just looking for feedback.
I have HEI on both my BBC and have no regrets with them they are great.
But Im looking to go to multiple carbs and the HEI is too large, so I have to go with a smaller disttrbutor.
I used the mallory back in the 70's , they worked great back then.
Not looking for a ignition system with an outside control box.

Thanks for your input.

 

[AutoGear]

Unilite is a great distributor if you are very meticulous about grounds. There was/is an inline filter to protect the sensitive electronics as well.
And keeping it clean is a big help as its an optical sensor.

ETA: Mallory "Active Power Filter p/n 29351" is the original. Since the Holley acquisition, the p/n is now 29371 with the exact same description.

 

[Key Largo Realtor]

Thanks for the P/N's

 

[57Nomad]

Small diameter HEI distributors may fit your requirement. I have made my own out of points GM 60’s vintage distributors. The parts, reluctor, magnetic pickup and modules are readily available cheaper than buying one all ready to install distributor. Yes there is cheap china junk available but it is just that junk. You can get fancy and machine the old points cam as I did or come up with your own reluctor mounting..

 

[BogiesAnnex1]

It you’re using a 6AL points are just as good as electronic switching as with these boxes the points are only providing a low amp on off signal to the 6AL which is doing the heavy power switching for the coil so the contacts of the points last forever. The big issue is what points always fought and that is not floating at high revs. But basically if your under 6000 RPM this isn’t a problem requiring racing points.

Bogie

 

[57Nomad]

Electronic boxes are expensive. They last only if your lucky and get a good one. I would not trust one to go cross country on road tour. Constantly seeing MSD units go bad. It’s not like a carbruetor that you open it up and fix it. If HEI goes bad throw it in trash. Too costly to toss an MSD. Maybe if you had extras MSD boxes then fine. Modules (HEI) are a lot cheaper even todays prices extras I have ran $20. Besides GM ran them for years numbering thousands upon thousands of cars. In fact ya might find HEI modules still in junk yards that work just fine.

No not good for over 6K RPM’s but street use are fine. The box with points can have a fail safe if box goes bad just run on points. That is a good reason to retain points. At the cruise ins plenty of guys still running HEI. I use HEI no issues, its cheap, not a lot of wires to run. Doesn’t multi spark like MSD at lower RPM but I never was convinced that did any good. JMHO

 

[Key Largo Realtor]

Im not going tp go with a control box unit agreed, also looking into Pertronix they have a plug and play unit

 

[57Nomad]

I had issues (complete failure) with three of the Pertronix “points replacement”. This goes back 10-12 years.
I purchased two and was given one. They each worked fine for couple weeks or less than kaput. Just a heads up on my experience. Maybe today they are a better design.

 

[BogiesAnnex1]

There are a great many small cap distributors out there both points and electronic switching, just Google, “Small Cap Chevy distributor”, then stand back.

One needs to remember that the only reason the classic HEI is so large in diameter is GM chose to put the coil in the cap, it isn’t there for any particular technical reason. This moved final assembly of the ignition to a one step process by eliminating coil assembly to the vehicle firewall which included install time on the line and it eliminated parts as a bracket and mounting screws, even the can a conventional coil come in. You can sleep assured this didn’t happen without a cost study that showed the coil in cap saved GM money. My professional career in aerospace included doing and overseeing hundreds of these Design For Cost (DFC) or Design To Cost (DTC) projects, a reason why I‘m not enamored with finance people.

Bogie

 

[Key Largo Realtor]

I think it was a great idea, it eliminated a few trouble spots, wiring, coil wire etc. But they also increased the diameter of the distributor housing. Will check Google as you said, thanks for the info.

 

[BogiesAnnex1]

I run a Speedmaster/ProComp 7000 on Frankenmouse. This isn’t a recommendation nor condemnation just info.

This is originally a Bosch design in fact it’s module will interchange with the GM 4 pin and if you want to spend extra, Mercedes used this same module but ya gotta pay the man for a dance with their 4 prong beauty. This was used in a lot of engines in various specific configs from 4 to 8 cylinders in Europe an Australia. So for ProComp to pick this up was easy as it already had fits for Ford, GM and many other V8’s. But it’s basically 1960’s design think with the advance mechanisms both vacuum and centrifugal under the electronics plate so it ain’t easy to replace the vacuum can when it goes nor fiddle the centrifugal timing curve. You can but it’s going to be on the bench not on the engine. So that’s a demerit Because the vacuum advance can went out and one for the pain of recurving the centrifugal to my cam and gearing.

The other and this I think is variable between older and newer versions is it uses the standard GM .491 inch distributor shaft instead of the more common aftermarket .5 inch shaft. I’m sure .491 was another cost study result at GM. Back 7 years ago when I first played with this thing ProComp/Speedmaster did not specify whether their gear was Melonized or not but did offer a bronze gear which is nice with my roller cam but not long lasting on the street so I bought a new Chevy Melonized gear which comes complete with retention pin. So I pop the ProComp gear off and slide the Chevy gear on the shaft and pin it with my new Chevy pin. Then I whip the gear around in my hand to discover the has a back and forth slip, not a lot but you’d play hell getting steady timing and over time the accelerations will break the pin if not the shaft. So I pop the pin out and pull the gear. Laying out the ProComp parts next to the Chevy parts proves that ProComp uses a larger diameter pin. I measure both pins and pull drill bits from my index box. Set the new Chevy gear up on the drill press using the GM size drill to get the holes aligned then changed bits and drilled for the ProComp pin then stuck it all together again. A negative discovery easily fixed if you find it but I don’t think rises to the occasion of demerits.

Then I fried the module, that was on me as Frankenmouse was a shop test bed for different EFI’s and the occasional carb so it’s wired through a switch panel that allows manual control of the fuel pump and ignition or the use of a computer to run those and other engine/transmission functions. Since I converted it to a carb when I retired I just left the manual fuel pump and ignition functions without rewiring the key switch for control. Well I walked off for a couple minutes with the electrical all switched on but the engine not running. When I came back it was to a fried module. Stupid me but not a demerit on them.

So the 7000 was just a cheap buy to get by temporarily 7 years ago. The damn thing just trudges away so I left it as sort of test to see how long it will go. I do carry spare parts for it in cap, rotor and module and a complete Pertronix Flame Thrower just in case.

Bogie

 

[Key Largo Realtor]

You put a lot of time and energy into that distributor.!

 

[1971BB427]

Unilites are great distributors, but subject to failures due to high voltage conditions. This is fairly common with most cars having alternators that put out higher voltages than older generators did.
The modules Mallory sells will protect it from spikes, but there are other options also. If you run an MSD box ahead of the Unilite it has built in voltage surge protection, and the Mallory wont need other external protection.
Another way is to simply run an old points style ballast resistor on the 12v. feed ahead of the Unilite and that will clip voltage and protect the distributor. I did this on my BBC powered Falcon for a couple months when I sent my MSD box back for upgrades, and the engine ran great, and the Unilite was fine also. Once my MSD came back I removed the ballast resistor, and rewired the MSD box again.

 

[topfuel]

I have been running a Unilite dist. with vacuum advance in my BBC for 30 years. The same distributor and have NEVER had to replace the optical sensor. As stated previously, you have to have a good electrical system with proper grounds and most importantly, disconnect the distributor when you do any type of electrical work on the vehicle such including welding, hooking up a battery charger, etc.. Im also running a 29440 Promaster coil and a Mallory Highfire VI 685 box with ProSidewinder wires. I know this is more than what you are planning on using. I have run this setup with both nitrous and now with a blower. No matter what distributor you run, it is very beneficial to run one with vacuum advance if you are street driving it. An ignition box is also very beneficial as well. BTW, I have been using a Powermaster 160 amp alternator for 6 years now and it has had no detrimental effect on the ignition system. Proper size wiring and good clean grounds are key.

 

['48 Austin]

I've done Pertronix conversions of a points distributors for a number of customers with excellent results. I've also replaced many Unilite modules some because of alternator spikes due to bad grounds and some because they just plain failed. I called Mallory and the Tech guy said "the old modules made in USA were good quality and did well but voltage spikes will kill them. The new modules from China are junk and fail for no good reason". The Mallory Tech guy also suggested buying Pertronix Conversions. I was amazed he pointed me towards his competitor. As previously said Good Grounds are Essential. That means a ground Strap (not ground wire) from engine to frame, body to frame, and Battery to engine. Otherwise you'll have problems with any ignition or EFI system.

 

[Key Largo Realtor]

I have been running a Unilite dist. with vacuum advance in my BBC for 30 years. The same distributor and have NEVER had to replace the optical sensor. As stated previously, you have to have a good electrical system with proper grounds and most importantly, disconnect the distributor when you do any type of electrical work on the vehicle such including welding, hooking up a battery charger, etc.. Im also running a 29440 Promaster coil and a Mallory Highfire VI 685 box with ProSidewinder wires. I know this is more than what you are planning on using. I have run this setup with both nitrous and now with a blower. No matter what distributor you run, it is very beneficial to run one with vacuum advance if you are street driving it. An ignition box is also very beneficial as well. BTW, I have been using a Powermaster 160 amp alternator for 6 years now and it has had no detrimental effect on the ignition system. Proper size wiring and good clean grounds are key.

Good info, I use lots of heavy grounds and proper wiring. I also like to use a ground bar and 2 fuse boxes in my engine compartment, 1 box for switched on power. Makes it easy to add on different accessories.

 

[Key Largo Realtor]

I've done Pertronix conversions of a points distributors for a number of customers with excellent results. I've also replaced many Unilite modules some because of alternator spikes due to bad grounds and some because they just plain failed. I called Mallory and the Tech guy said "the old modules made in USA were good quality and did well but voltage spikes will kill them. The new modules from China are junk and fail for no good reason". The Mallory Tech guy also suggested buying Pertronix Conversions. I was amazed he pointed me towards his competitor. As previously said Good Grounds are Essential. That means a ground Strap (not ground wire) from engine to frame, body to frame, and Battery to engine. Otherwise you'll have problems with any ignition or EFI system.

I opted for the Pertronix flame thrower distributor and coil. It does have an adjustable vacuum advance also. Good feature as I wont have to make a stop plate. Still plumbing the carbs so I havent had a chance to start it yet.

 

[57Nomad]

Pertronix replacement for ignition points does nothing that a well set of point does. It only makes and breaks the feed to the coil. If you want more zap you need an ignition module, amplifier or CD system. Many of them work with points or magnetic pickup.

Honestly on a street car an HEI system is about all you will need. It‘s not as reliable as points because the module quality today is questionable at best. But if you obtain a good original with variable dwell, they do work.

 

[Key Largo Realtor]

Pertronix replacement for ignition points does nothing that a well set of point does. It only makes and breaks the feed to the coil. If you want more zap you need an ignition module, amplifier or CD system. Many of them work with points or magnetic pickup.

Honestly on a street car an HEI system is about all you will need. It‘s not as reliable as points because the module quality today is questionable at best. But if you obtain a good original with variable dwell, they do work.

I had to remove the HEI distributor, it wouldn't fit with the Weber carbs. So I was looking to see what some of the options that people were happy with.

 

[57Nomad]

There is a guy that converts the small diameter distributor to HEI. There is another option is convert one yourself.

I converted four of my cars to HEI, I wire module remotely On aluminum heat sink. Also find my wire diagram.