Pertronix Ford Performance Dual Point Distributor

[sprdv1]

It’s an Autolite.

http://[URL]https://photos.app.goo.gl/5989AjotyUDkdaGFA

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those always seemed to be a good brand for the $$ hmm

 

[sprdv1]

Pertronix in the dual point would eliminate the constant maintenance issue. Been looking but haven’t been able to find a correct stock single diaphragm one. Not sure exactly the best place to look and not exactly sure what part number to look for.

Could always try local store, see if someone has some knowledge

 

[f2502011]

Here are a few pics of behind the ignition switch and the harness under the hood. I don’t see a separate connector under the dash near the firewall but do see one on a blue wire under hood that’s not being used for anything. Would that be what I’m looking for?? There’s also a black connector but that’s part of the 71-72 emissions. Can’t remember what it was called but it changed tuning based on temp. Has a little thermostat in the driver door jamb.

I purchased a pertronix for the dual point and a flame thrower coil. I read the stock coil and resistance wire can be used with pertronix as long as overall primary resistance is between 1.5 and 3.5 ohms. I tested the factory coil. It’s 1.9 ohms with my meter that won’t zero and reads 00.5 on the 200 setting. Pertronix 1.5 ohm coil reads 1.8. Red/green wire to distributor reads 2.0 switch on. This would put me over the 3.5 limit either way without a bypass. What should I do? The stock and flame thrower coil are pretty much the same.

3 new items by Homeowner A

photos.app.goo.gl

 

[DirtDonk]

I think I see the resistor wire going straight to the ignition switch on yours. To bad…
But I also see a couple of unusual red with blue stripe wires under there as well. Normally you will only see one on a 72 model. Maybe they were just some cuts and splices as it looks like, but it’s interesting so I thought I would note it anyway.

The blue wire under the hood is probably for the old anti-dieseling solenoid. That might work, but easy to check with a voltmeter.
See if it’s got power with the key in the on position and in the ACC position. If it’s hot in the ACC position, you probably don’t want to use it.
If hot in ON only, you’re good to go.

So that big wire is the ambient switch circuit? Wow, that’s heavy gauge. Wonder why…

 

[f2502011]

I think I see the resistor wire going straight to the ignition switch on yours. To bad…
But I also see a couple of unusual red with blue stripe wires under there as well. Normally you will only see one on a 72 model. Maybe they were just some cuts and splices as it looks like, but it’s interesting so I thought I would note it anyway.

The blue wire under the hood is probably for the old anti-dieseling solenoid. That might work, but easy to check with a voltmeter.
See if it’s got power with the key in the on position and in the ACC position. If it’s hot in the ACC position, you probably don’t want to use it.
If hot in ON only, you’re good to go.

So that big wire is the ambient switch circuit? Wow, that’s heavy gauge. Wonder why…

Blue connector has 12.5 volts in on position and 0 in ACC. So I’m guessing I would run a bullet connector and wire from the blue wire to the pos side of coil. Hook pertronix red there as well black wire to negative side and just not use the factory red green wire??

 

[DirtDonk]

Correct. As long as the coil and Pertronix say that 12V is the way to go, that looks like the perfect set up.

 

[f2502011]

Had a chance to install. Runs well but hard to crank (tough to turn over) as if the timing is too advanced. Didn’t mess with distributor position/timing. Guess changing to a pertronix is like changing dwell so I’ll at minimum need to check my timing. Any ideas if it might be something else? I just did a google search and it seems many people have this issue with different makes and models, but they will move the distributor/change timing and then it either won’t run at all or run way worse.

What are the timing specs for these?

 

[DirtDonk]

It's no different from changing points. You mess with them at all, you change the timing. You change them at all, you change the timing. You mark the distributor, pull it and put it back in lined up with the old marks, and you probably still changed the timing.
No matter what you are changing inside a distributor it's just good practice to re-check and reset the timing.
Probably says it right in the Ignitor instructions somewhere unless they changed them.

So yes, you are probably on the right track thinking it's too far advanced. It's also got a stronger spark most likely, which in some cases might actually act like this at a lower ignition advance than with the old weaker spark. Not often, but it's possible.
Get the light hooked up and see where it is. If for no other reason than curiosity to see if it changed, and if so how far.

Paul

 

[f2502011]

It's also got a stronger spark most likely, which in some cases might actually act like this at a lower ignition advance than with the old weaker spark. Not often, but it's possible.
Paul

How would you compensate for this particular situation stronger spark lower advance? Same way just adjust timing or something else? Also seems to idle faster and the exhaust doesn’t smell as clean.

 

[DirtDonk]

Yes. If your combustion chamber reacts that way to better spark, you simply retard the ignition timing. You should (again, in theory) not have to go lower than stock specification, but if it was already bumped up a bit like most of us do, then rolling it back a couple of degrees should do the trick.

But chances are better than even that the new install simply advanced the timing a bit more than the engine was happy with. At least that's my story and I'm sticking to it.

The other common ignition timing scenario on our particular engines (289, 302 and 351 Windsor) is incorrectly located timing marks and/or pointers.
If yours is an original engine with all original front belt drive assembly and original damper, then the timing marks should line up perfectly with the pointer. Unless the damper ring has slipped...
But if any of those things have been changed in the past, all bets are off until you verify that the pistons, damper marks and timing pointer all match up correctly at TDC.
Too many variables until confirmed.

Paul

 

[f2502011]

Yes. If your combustion chamber reacts that way to better spark, you simply retard the ignition timing. You should (again, in theory) not have to go lower than stock specification, but if it was already bumped up a bit like most of us do, then rolling it back a couple of degrees should do the trick.

But chances are better than even that the new install simply advanced the timing a bit more than the engine was happy with. At least that's my story and I'm sticking to it.

The other common ignition timing scenario on our particular engines (289, 302 and 351 Windsor) is incorrectly located timing marks and/or pointers.
If yours is an original engine with all original front belt drive assembly and original damper, then the timing marks should line up perfectly with the pointer. Unless the damper ring has slipped...
But if any of those things have been changed in the past, all bets are off until you verify that the pistons, damper marks and timing pointer all match up correctly at TDC.
Too many variables until confirmed.

Paul

Just checked timing at idle granted it idles fairly fast right now I’ll have to hook up my tach and dwell meter, but it seems to be around 1500 or so. Took longer than usual to crank but cranked right up. Used a dual back timing light and got 44. I don’t know anything about dual point distributors but know that’s way too much. Don’t hear any detonation, but I’m also thinking like you said the timing marks are incorrectly located. It’s the original engine but I’m sure front components have been changed. Had a Ford 428 that I had to tune by ear for the same reason. Using the numbers and marks was completely unreliable when you tried to time to spec.

 

[DirtDonk]

The high idle is a dead giveaway that your timing is advanced.
As you retard the timing your idle should come back down. Right now you could probably just retard the timing until the idle sounds more normal and lock it in at that until you get the timing light hooked up.
Then do some fine-tuning later.

Can’t say this is true for all engines, but my 71 302 almost never give me a ping for any reason. In fact I advanced my base timing all the way up past 20 to the point that it ran like crap. But it still wouldn’t ping.
Luckily we have timing lights!

 

[Broncobowsher]

With 44° you are probably not getting any detonation as you are getting a full burn before TDC. Timing so advanced you don't get it.
And that will be a hard starting engine if the ignition is any good.

You can get some wild timing settings when "tuned by ear" and vacuum gauge.

 

[f2502011]

With 44° you are probably not getting any detonation as you are getting a full burn before TDC. Timing so advanced you don't get it.
And that will be a hard starting engine if the ignition is any good.

You can get some wild timing settings when "tuned by ear" and vacuum gauge.

What should the timing be? I dropped it to 20. Cranked right up and smooth. Went to 15 didn’t idle as well still cranked right up. Went to 18 little smoother. Exhaust smells much more normal and it has a tough sound. Is 18-20 ok? Most I think are 10-14. Think stock is 6 but there’s just no way with this one to get there.

 

[Broncobowsher]

No solid answer. 20 sounds a bit high. Might still have some hard starts. 6 is good for emissions. If I don't know anything about an engine I just set it at low teens and start from there.

 

[f2502011]

It likes 20 the best so I’ll leave it there. Cranks with barely a turn of the key. Has a 4 barrel. Seems others with similar setup not necessarily in a Bronco but with 302-4 barrel combo have had the same experiences.

 

[f2502011]

Had a chance to drive some today. Has some hesitation issues at low throttle. Almost as if the vacuum advance or accelerator pump are bad. Doesn’t have vacuum advance so that rules that out. Also has a high pitched almost vacuum cleaner sound at idle. Possibly a voltage issue?? Could I run a completely separate wire from the back of the ignition directly to the coil? Would leave all other wires in place. Including the resistance wire it just wouldn’t be hooked up. This would bypass factory harness altogether vs coming off the unused blue factory plug at the firewall in the engine bay. Messed with timing a little. Down to 13-14 now initial but made no difference in hesitation/stumble.

 

[TDubya]

My 75 w/302 and Holley 4160 has initial timing set at 14 and total mechanical at 34. I know the timing marks are correct. I have played around with initial timing anywhere between 8 and 18. I've never noticed any detonation or hard starting at 16-18, but backed off to 14 because I didn't notice any performance gains and didn't want too much total advance to be safe. 14 also works well with my idle speed and having the transfer slot adjusted correctly. Its funny how very similar engines like different timing.

 

[f2502011]

My 75 w/302 and Holley 4160 has initial timing set at 14 and total mechanical at 34. I know the timing marks are correct. I have played around with initial timing anywhere between 8 and 18. I've never noticed any detonation or hard starting at 16-18, but backed off to 14 because I didn't notice any performance gains and didn't want too much total advance to be safe. 14 also works well with my idle speed and having the transfer slot adjusted correctly. Its funny how very similar engines like different timing.

If I drop this one below 18-20 initial it splutters mid range. If I blip the throttle seems overwhelmed and splutters unless I raise timing to that range. It acts like it wants more but I’m afraid to do that. I went 10,12,14,16, 18, 20 and with each step, idle got smoother and the mid range splutter was less and less.

It Idles and runs fine either way at lower or higher rpm regardless of timing. I’ve been all the way down to 6.

It’s almost like it can’t burn the fuel it’s getting mid range. If you feather foot it, it doesn’t like it and that’s where I would like to run. Cruising casual driving.

Could also be a heat issue. It’s 100+ degrees outside ambient temp and I had to use really thin carb and air cleaner gaskets so the hood would clear the air cleaner. Has a higher rise intake.

 

[DirtDonk]

Some of the things you describe could easily be fuel related.
A lean condition from either a vacuum leak, or lean overall jetting, or not enough accelerator pump squirt.