Decided it was time to look at the ignition system on my ‘66 352. Distributor and rotor looked pretty haggard.
Back in the day it would have been pretty simple but now way too many choices. The plugs in her now are Autolite Double Platinum (whatever that means). I pulled a couple and found they were gapped around .025. These seem to work but what should i gap the new plugs at? It has the pertronix point system, will have a 45,000 volt MSD coil.
Was advised the coil which lays horizontally shouldn’t be oil filled so ordered an epoxy filled. With the pertronix do I need a ballast resistor? And if so where does it go, don’t see anything like that under the hood anywhere.

i haven’t bought parts like this for 30 years or so, sorry for so many questions.

thanks for being a great resource!

 

In Ford cars and trucks the ballast resistor is incorporated into the wiring harness itself, known as the "pink wire" coming from the ignition switch under the dash. It isn't a separate wirewound ceramic unit on the firewall or anything like that. Whether it's needed actually depends on the ignition coil. In most cases it is not necessary or desired, because most people opt to use the higher output Flamethrower coil. One of the ways a higher coil output is achieved is with a higher input voltage.

There isn't really a benefit for platinum spark plugs in these motors, conventional plugs are fine. I like NGK. I would advise using the stock plug gap of .035" at least to start out with for tuning purposes, ignition is actually a little tricky and the distributor itself is a points & condenser unit. Pertronix says opening up the gap .005" is OK. Most people don't have that much accuracy when using a feeler gauge and I doubt it makes too much difference.

I would also suggest testing the distributor ignition timing from square one. Make sure the balancer hasn't slipped the timing marks, make sure the centrifugal timing is working correctly and advancing at RPM like it should and, that the vacuum advance is working correctly. These old trucks have a lot of miles, a lot of hours, so a Tune-Up is a little more involved, a little more checking to do, than when they were only a few years old. Worn out or high mileage distributors cause a lot of hard to diagnose issues.

 

Update of this. I replaced the dist cap, rotor, wires and plugs. I went whole hog and bought the same plugs as it had in it the Autolight super-duper dbl platinum 5 buck plugs. The cap and rotor look like stock sold by MSD. The plug wires are am 8mm the original were 7mm but I don't think size matters in this. It had the pertronix points replacement module in it and I left it alone.
I replaced the plug wires one by one, using the firing order diagram I had, and gaped the plugs to .035.

I decided to try and establish a base line on timing since I didn't know what I was dealing with. The crank had a yellow stripe on it but the markings were long gone. I put #1 at TDC and discovered the distributor had been installed a tooth off. I checked the firing order was correct. So I "fixed it" reorienting the distributor. So #1 at TDC, rotor pointing at #1 plug wire and fired it up. Disconnected and plugged the vac advance and timed it to what I guessed at about a 15 degree advance. Seemed to run and rev just fine. Took it out for a test drive and ran fine for the most part. Felt a little rough so I decided to look at the timing with a vac gauge. Vac was about 19 inches and fairly steady. In order to get it to where it seemed to pull the best and steady vac I had to advance it so far that the vac advance unit hitting a bracket and I think I discovered why the PO had moved the dist a tooth, so the dist could be rotated far enough to set the timing better, So I reoriented the dist to where the PO had it. Using the light the timing looks pretty far out but I can adjust it for a good idle, and a steady 19 inches of vac. Runs OK but feels under powered just slightly less smooth, but that might be in my head. So I doubled checked everything and it all is where it ought to be.
I haven't checked for vac leaks yet but I did put a meter on the new vs old plug wires. The old set on a 30 inch plug wire I tested was 14.5k ohms vs .6 on a new wire the same length. Now I'm wondering if this low resistance vs higher resistance plug wire might be coming into play.
I haven't touched the carb thru all this, strictly ignition stuff.
Feels down on power and less smooth.

So I'm asking this learned body here, anybody got any ideas?

 

Whether you need or do not need a resistor in the coil supply circuit depends on exactly what coil type you are using and what the manufacturer's instructions tell you to do. You need to know if the coil is rated EXTERNAL or INTERNAL RESISTOR.

With PERTRONIX (depending on which version) and the correct coil, it will fire the fancy plug. Usually you can go out to .060 with no problems (.035 w points - .045 with DSII). It delivers a hotter fatter spark, usually for lean fuel trim emissions rated engines or a fat fuel curve in a carburetor engine.

The PLATINUM tip(s) are less prone to foul.

 

Setting the baseline for timing as you describe it is a good idea, but the only way when dealing with old iron these days is first make sure the timing marks are still accurately located on the balancer.

It is super common for older balancer rings to slip. This makes setting the timing problematic. An inexpensive tool called a "piston stop" works best to check for this. Or just an 18mm long bolt will work. All that's required is to simply make sure when #1 piston is at the true TDC it coincides with the "0" mark on the balancer. Then you know this part of the initial setup is OK and the timing marks can be depended on for everything else that follows.

When testing manifold vacuum a stock factory engine, 19" is good, but the gauge needle should be absolutely perfectly steady, "fairly steady" sounds to me like the vacuum test is indicating a defect of some kind.

 

The reading would drop an inch maybe 3-5 seconds between dips.
this does have an after market cam installed some time in the past. Supposed to be mild.

 

And confirm timing chain integrity.

EDIT -

 

I was told the opposite by a mechanic 20 years ago. He stated that platinum plugs work great on EFI because they maintain a good A/F ratio whereas carbs will run rich under many conditions in order not to run too lean under others and running rich will foul platinum plugs faster than regular plugs. Having said that, I have no personal experience with them in a carbureted engine, so I'm interested to hear real world results to either confirm or dispel that claim.

 

I haven't found a vac condition that matches what I'm seeing. I'm going to replace the PCV and check for leaks in the near future.

As for the platinum plugs here are the ones that were in the engine. There were gaped from .025 - .035. I have no idea how long there were in there. To my eye they don't look too bad. Skosh on the dark side perhaps? The oil on the base and threads is from formally loose valve covers.

 

OK ...

PLATINUM plugs were introduced to withstand the increased voltage of an electronic IGN system, which can go to 40,000 plus volts, plus severely reduced fuel trim with greatly increased heat within the cylinder due to less fuel being introduced..

The higher voltage would burn then used copper plugs up in a short time. The PLATINUM was introduced to give longer service life and be able to withstand heat generated by the lean fuel conditions (emission compliance - fuel economy)) of EFI. Any plug will foul given the right conditions, weak IGN, fat fuel or oil foul.

If an early carb'd engine has it's fuel curve dialed in, the use of PLATINUMS in a earlier engine is warranted (IMO) If you have a hot street engine, you would want to use copper as you will be fine tuning more often anyway.

You have to realize just because someone works on cars or is employed in a repair shop does not necessarily make him an expert (as neither does it me). With today's TECH, one must be in constant learning mode and frequent trips to the TOOL TRUCK of his/her choice.

 

DOUBLE tip means both electrodes are PLATINUM. These are SERVICE REPLACEMENT PLUGS. OEM ASSY used plugs with only one or the other electrode tipped as the IGN SYS would actually fire twice (reverse polarity) and to keep assembly cost down used single tip.

DBL PL makes it easier for service, especially outside of a dealership.

If you ever pulled the plugs out of such an engine, you would see they had different PN's.

Listen. Refer to your PERTRONIX INSTR SHEET. They will give gap recommendations (usually .045 on a CARB ENGINE). Once you have it back together see how it runs, The slight blip may be a mis-fire. Your IGN SYS sounded like it needed CPR.

Did you purchase PERTRONIX I, II or III?

 

Thank you patience experts!
The Pertronix was installed when I bought the truck. See the pic, I don't know if it's a II or III.
In looking at the PCV and such I noticed the PCV valve doesn't have a spring, just a piece rattling up and down.
And while testing at the vacuum once again it does indeed sound like a mis-fire. New plugs, new wires (low resistance), new rotor and dist cap, new coil (MSD 8222 Blaster II high vibration) timing set and reset. The plugs are gaped to .035 so they should at least be in the ball park. I have 8-9 volts to the coil while running, It's a digital multimeter so that's an avg.

Where should I look next?

 

You have the PERTRONIX I. Is the module receiving BAT VOLT (12V) or is it wired through the resistor? The module calls for 12V.

The coil you chose calls for a resistor. Being a 1966, there should be an inline resistor wire @ the IGN SW harness (originally a points system).

Are you satisfied the IGN TIMING is correct? Did you verify TDC?

Vacuum reading 19" and steady? Does vacuum go up with timing advance and carb balance adj?

 

The coil gets 12V when not running and around 9V while running. I believe this indicated the resister is in play?
TCD appears to be correct on the dampener #1 at top and dampener on the mark.
Because the timing marks are not readable except the the mark made where it looks to be zero I set the timing to approx 15 BTDC then put the vac gauge on it and advanced it till I got a max vac of 19 and retarded it a couple. Vacuum advance disconnected and plugged. The Vac holds steady at 19 with a periodic drop of 1 inch and then back to 19. To my ear it sounds like a misfire.

Looks like the Pertronix gets it's voltage from the + side of the coil so that would be around 9V while running.
The coil needs the ballast resister but the Pertronix doesn't? Is that a problem?

 

Pertronix says their Ignitor II and III want this relay but they don't mention the Ignitor I

From the Pertronix site:
https://pertronix.com/pertronix-2001...ription_tabbed