Which system provides a crisper, more accurate timing signal - Unilite or Pertronix?

chepsk8 · Feb 6, 2008

I know this subject has been covered in the past, but I am asking again for a fresh opinion. Both are good, both have supporters. No arguments there. I have always used the Uni-lite systems with great success. At 6500 RPM on the track, no mis-fires with the Unilite, and using a Crane HI-6 Ignition box in the Cobra.

I am doing a conversion in the spring, and am planning the following system:

Internal distributor electronic conversion (Unilite or Pertronix).
45 KV coil
8mm Black silicone wires
Hi-Perf Dizzy cap
Fresh plugs gapped at .040

I did this conversion on Chepie and the SCJ, both kept the stock look, and never fouled a plug again.

So, which system, Pertronix or Unilite, seems to run better & keep time?

Related question - Were you able to keep vacuum advance, and what were your initial timing settings? did you keep 6 degrees BTDC, or advance more with the hotter spark? the car is a 289 2V with Auto and 2.80 gears. I must also note the owner is a lady here, and VERY particular about her car.

Many, many thanks guys!

Dan

TD68302 · Feb 6, 2008

Unilite is the only thing that I have ever used, and it has ever done me wrong. As far as timing you are on your own there.

bnickel · Feb 6, 2008

other than a fewpopped modules from a bad batch mallory had back in the early 90's my unilite has served me very well over the years and i don't think i'd trade it for a pertronix. my car has kept the vacuum advance and i found a new goodie for original style vacuum advance canisters too, it's an adjustable vacuum advance system that utilizes the stock vaccum can so it remains stock looking under the hood

http://www.cougarpartscatalog.com/adjf01.html

12sec67 · Feb 7, 2008

I just had to replace a customers Unilite distributor because it wasn't keeping accurate time.

In your case I would go with a pertonix ignitor and coil although I would never get a pertronix distributor. The pertonix distributor cam gear pin is thin and cheap and I have seen one come apart first hand.

bnickel · Feb 7, 2008

12sec67 said:
I just had to replace a customers Unilite distributor because it wasn't keeping accurate time.

In your case I would go with a pertonix ignitor and coil although I would never get a pertronix distributor. The pertonix distributor cam gear pin is thin and cheap and I have seen one come apart first hand.

yeah but we're talking about a mallory unilite conversion for the stock dizzy not a whole mallory distributor

ForceFed70 · Feb 7, 2008

As far as accuracy goes, the slop in the stock distributor (especially after a few years/miles under it's belt) will throw out the timing more than either of the conversion modules you mentioned, so I wouldn't worry about the accuracy.

With my pertronix I was able to keep both the vacum and mechanical advance (didn't even need to mess with them).

65ShelbyClone · Feb 8, 2008

Here's another wrench in the works:

How do the Unilite and Pertronix compare to a Duraspark?

12sec67 · Feb 9, 2008

I replaced my pertronix 2 times then went to a duraspark which never went out then upgraded to MSD.

1 vote for Duraspark

chepsk8 · Feb 9, 2008

While I agree the duraspark would be the best answer, I have to work within the parameters of stock appearance. Black 8mm silicone wires, paint the Hi-Perf coils black, hi-perf, but stock looking cap, etc. so, my choices come to three (accel also has an optical kit) for the under-cap conversion. My goal is to provide a very hot spark and maintenance-free system. while being as undetectable as possible.

Just for comparison, in the Cobra, I have billet Unilite distributor, Crane Hi-6 box & coil, 9mm wires. That system fired the original motor with water in the cylinders! Ihave yet to loose a plug with it.

bnickel · Feb 9, 2008

the accell system is really just a lower cost version of the unilite.

Pakrat · Feb 13, 2008

My only experience has been with pertronix but it has yet to fail me, with the flame thrower coil I have been very happy. They even claimed I could only use it with a stock dizzy but I was able to modify it and ditch like a 3rd of the parts and make it work just fine with my Accel Mechanical advance unit. I ended up at 13* BTDC for my optimal timing FWIW.

bnickel · Feb 13, 2008

Pakrat said:
My only experience has been with pertronix but it has yet to fail me, with the flame thrower coil I have been very happy. They even claimed I could only use it with a stock dizzy but I was able to modify it and ditch like a 3rd of the parts and make it work just fine with my Accel Mechanical advance unit. I ended up at 13* BTDC for my optimal timing FWIW.

i think the pertronix ignitor 1 is fine it's the ignitor 2 most people have a problem with. a unilite with an msd blaster coil is an awesome daily driver ignition combo though, starts right up every time and calms the idle down nice too.

on the cougar i think i'm either going to use a unilite converted stock dizzy or a duraspark dizzy either one with an msd blaster ignition box and blaster coil. i have spare parts for either combo so i just need to decide which way to go. i'm thinking i'll have a little better control over the advance curve with a duraspark dizzy though. of course if i go EFI it'll be a completely different system altogether.

Pakrat · Feb 13, 2008

Oh right, the cougar. You know, a great name for that car would be Nessie.

66Runt · Feb 13, 2008

If the car is stock, you're really not going to excersize either one. Unless you end up with a high resistance issue on the secondary side, you shouldn't see more than 15KV at the plug. Unilite is digital, where Pertronix is A/C Volt sine wave converted to digital. But the "real world" difference is esoteric.
Best bang for the buck is to make sure the voltage drop on the B+ and B- side is less than 0.2V. I like to make sure the ground cable from the engine to the body is connected to a good clean metal surface. Same with the ground cable to the engine. Also, I am very picky to insure the ignition switch is in excellent shape. That gives me exceptional performance on either module. I also prefer to keep the primary ignition circuit side isolated from anything else. I run isolated relays for other items that require an "ign" source. This way if anything else fails, it does not effect the ignition system.
I pretty much let the customer choose. I do explain that there is a bit of maintenance on the Unilite (periodic cleaning of the optical sensor), and with the pertronix I explain the need to use brass feeler gauges for setup. But I have no personal preference for either one, in a well maintained vehicle.
Definitely keep the vacuum advance. Fuel and compression dictates timing, and timing curve.
Good luck!

bnickel · Feb 13, 2008

Pakrat said:
Oh right, the cougar. You know, a great name for that car would be Nessie.

hmmm, i'd have figured you for a "Champ" kinda guy, personally. right now it's definitely my unicorn for sure. hopefully i'll be able to bring it home either this weekend or next, just waiting on the old tax return check to come in. here's another car that is similar looking to mine.

Pakrat · Feb 13, 2008

Champ? Don't ya mean Chump?

I was thinking Nessie cuz' we are always hearing about the f***** but we never see it.

bnickel · Feb 13, 2008

Pakrat said:
Champ? Don't ya mean Chump?

I was thinking Nessie cuz' we are always hearing about the f***** but we never see it.

have you never heard of Champ? he's the American version of Nessie, from Lake Champlain

http://www.genesispark.org/genpark/champ/champ.htm

Pakrat · Feb 13, 2008

Oh that champ, I thought you meant Jon Voight.

bnickel · Feb 13, 2008

you are one sick, twisted puppy... but of course we all knew that.

htwheelz67 · Feb 13, 2008

you cant beat a good rebuilt stock duraspark, in fact you can take your stock dist and put duraspark internals in it. All the aftermarket dist'sand conversions are decent and as far as timing goes under 7000 rpm you will see no difference. Now say your driving away from home and your pertronix or unilite goes out, can you go to your local auto parts and get a replacement part right away? I dont think so......MSD uses ford type internals in their dist's though.

My suggestion is get a good quality rebuilt duraspark dist (about the same price as conversions) 76-80 truck are good years, a "blue strain" module or better an msd or accell 300+ ignition and coil or any good ignition controller and use it in place of the module. In my case I use a 300+ and I wired it so if it fails I can plug in my stock duraspark module if it fails.

Which system provides a crisper, more accurate timing signal - Unilite or Pertronix?

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