Timing issues with Pertronix conversion on '54 Merc 256 Y-block

Having a hell of a time getting my engine running right after installing a Pertronix system in it. It's a '54 Mercury, running the stock 256 Y-block, newly rebuilt stock carb, pretty much stock everything else besides the 12V neg ground conversion I did on the car a couple years back. The car is an automatic.

I set the timing with the vacuum disconnected from the distributor, like you're supposed to... and it seemed to run fine. As soon as I hooked the vacuum back up, it start popping and backfiring (both out the carb and the tailpipes) when giving it any gas.

I have the timing set at 6* BTDC
I've double checked the firing order of the wires.

Is there a change in timing setting with the Pertronix vs. the original points setup? From what I've been able to find/read, it sounds like the original timing setting stays the same.

Any help great appreciated, thanks!

-Steve

 

You shouldn't need to change the timing. I think that the pertronix units help generate more voltage than the stock points set ups. Did you swap out your old coil? It may have had some sort of weird shock and does not want to handle the new equipment.

 

Oops, forgot to add that part. Yes, I swapped out the old coil with a new one I bought with my Ignitor unit.

Thanks for the response.

 

Hello
We just went through the same problem at the shop.

If you have your ignition timing correct, the problem is probably your power wire to your coil. A lot of cars have a ballast resistor in-line in the ignition wire. If your coil has an internal ballast as most of the "blaster" coils that come with pertronix have, then you have double ballasted the coil, and you are not getting enough juice to it. ALSO, check to make sure that your ignition wire does not have a "resistor wire" in line. These are either short wires or can be very long sometimes from the ignition switch to the firewall. These new coils need a good amount of voltage under load, not just to the coil when it is not "on".
To check if this is the problem, just run a good wire from the battery to the + side of the coil and see if that fixes it. It probably will.
If it does, then you can check you ignition wire by: connect the neg. side of the coil to ground, then turn the ignition on, then read with a voltage gauge from the positive side of the coil how many volts show. You need (check manual for exacts) at least 8volts still, but I think it might be at least 10 volts to the coil. I am not at the shop now, so check that out.
Good luck.
let us know
Wil Sakowski
www.sakowskimotors.com
Open house April 19th, 2008 2-7pm
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I'm not sure what the problem his, but a word of warning. The 54-56 Yblock distributors (loadamatics) worked differently than the ones we normally work on. There is no mechanical(centrifical) advance in the distributor. All advance is by vacuum, and its vacuum source is different than what we normally are used to. Maybe this has something to do with it, but I am not sure. I haven't any experience with the loadamatics.

I would check with a Motor or Chilton manual on setting timing with a loadamatic distributor.

 

dude i know this problem exactly. The pertronix unit advances itself per say. do not hook up the vacuum advance and you'll be fine. I've been running my for over 4 years and no problems yet. hope this helps.

 

i put my petronix unit into my 53 lincoln y block without any problem, strangewise i had to clean the carb to run prober after th swap ,before it run prober without to clean the carb ??

 

had the same problem, the pertronix is located wrong on the breaker plate, pertronix couldnt help me, thought by now they would have this figured out, we figured it out on our own, when the vacum adv comes in, the plate moves too far and fires the plug next to the one its suppose to, well its a cylinder out of sequence and back fires thru the carb and exhaust, the squirrel could explain it better if he was around, he helped me on this one we did, 1955 272ci, anyway they have the pertronix located to far advanced on the plate, it has nothing to do with the static timing, you can still time the engine, but as soon as the plate moves, it fires the next plug, I moved the pertronix on the breaker plate, worked fine, I tried to limit the breaker plate at first, but it didnt work, like all this stuff we buy its all junk in my opinion, whats wrong with points? try leaving the key on with a pertronix, 75.00 down the drain, it will burn out, probably when your 500 miles from home. have fun