How do I time this thing?

[sabrie]

Inadequate initial ignition timing can cause a few problems. Sluggish performance, excessive engine heat, and hesitation on acceleration.

I mentioned above that I use a dynamic timing approach to set timing when I suspect the harmonic vibration dampener timing ring has slipped (or when I can't fine timing marks). This is an old school timing technique shown to me be an old school technician who used to race competitively. I found his technique to be effective, and in fact fairly well known with a few different twists here and there. I offer it for informational purposes as opposed to being either educational or suggested. If someone gets too aggressive in setting their base ignition timing advance serious damage to the engine may result. If the steps below do not make sense, even intuitively, or you feel uncomfortable doing this - stop and move on to some other subject. This is not for everyone, your results may vary depending on your overall situation. The background approach upon which this technique is based is to get the total ignition timing (initial, vacuum, and mechanical advance) to come in at or near their collective maximum level. With the engine RPM at 2,000 - 2,500, in neutral, and the vacuum advance hose connected to the vacuum advance diaphragm the ignition timing is adjusted one way, then the other, until (using a tachometer with, or without a vacuum gauge) the maximum RPM level is attained with the carburetor throttle in a fixed position. Here are the steps I take:

• Connect a tachometer to the engine, and verify it is working correctly,
• Optionally connect a vacuum gauge to intake manifold vacuum,
• Test the distributor vacuum advance diaphragm to ensure it is not leaking or ruptured,
• Make certain Ported Vacuum is being sent to the vacuum advance distributor canister when the carb throttle is being opened off idle,
• Connect the vacuum advance vacuum hose to the diaphragm canister,
• Loosen the distributor retaining bolt just enough to allow you to turn the housing clockwise and counter-clockwise, but do not leave it so loose it can turn by itself when the engine is running,
• With the engine at normal operating temperature, and the distributor vacuum advance diaphragm is connected to its appropriate vacuum source (typically Ported Vacuum), use the choke linkage high speed cam setting to attain an engine RPM at 2,500 RPM,
• Looking at the tachometer turn the distributor SLOWLY in the counter-clockwise, then clockwise direction, back and forth with decreasing back and forth turning movement as you try to get the highest RPM possible without having moved the throttle opening.
• If you are using a vacuum gauge the vacuum reading should also be at its highest setting attainable vacuum reading with moving the distributor housing clockwise and counter-clockwise,
• Once you have zeroed in on the maximum RPM level, retard the ignition (counter-clockwise for Ford 302 and 351 engines) until you have reduced the RPM to being 200 RPM less than the maximum you had previously attained - then disengage the high speed idle cam and let the engine return to its normal idle RPM,
• Tighten down the distributor housing adjustment/retaining bolt (not overly tight, snug is fine),
• Disconnect the distributor vacuum advance hose
• Using a timing light to see what your initial timing BTDC is, and write it down. It may be far different than where it is expected to be in the event the outer vibration dampener ring has slipped,
• Usually, with decent fuel, I find most engines find their happy spot with the initial ignition timing at between 10 and 14 degrees BTDC, usually 12 degrees on Ford small block engines,
• Disconnect the test equipment, put the air filter housing and filter in place, then take the vehicle out for a test drive,
• Listen for any pinging on light throttle acceleration, as well as heavy load acceleration. If you hear any "significant" pinging make further adjustments as needed to get rid of it (slightly retarding the timing advance). Keep in mind, for an adjustable vacuum advance diaphragm tension spring (inside the vacuum canister inlet), with the spring tension being too light it is possible to introduce light throttle pinging, so I would begin there to reduce or eliminate the light throttle pinging.

You ought not do this with computer controlled engines, as it is possible you may be picking a fight with different sensors and systems and really foul things up. You may, in fact, not be able to do the above process as often computer controlled engines do not let their ignition timing to be changed by loosening the distributor housing and turning it one way or another. But, just in case you have a system, especially an aftermarket system, that is computer controlled for any reason, do not use the above process.

Thanks for the great response. I still need to check to see if I have the balancer marked correctly but I did do some tuning by RPM and so far it is running. I may still have another issue, but will keep working on it.

 

[sabrie]

While I have no experience with timing a 302, I do have BAD experience with the Pertronix Ignitor III. I'm not going into the full story, but back in 2012, my engine builder installed a P III in my engine. It proved to be nothing but problems. I eventually tracked the problem to the crappy way Pertronix constructed the PIII for the Ford distributor. Instead of using a bearing between the two plates, as is in the DuraSpark distributor, they chose to use a plastic "bearing", that wore out within weeks, causing the air gap to increase/decrease as well as the top plate could be seen to move upward. This was revealed on a distributor machine. This meant that the timing was moving all over the place. I sent this POS back to Pertronix and although they would not admit the problem, they did replace it with a PII and matching coil without question. That PII has been in my car since without any issues. My 351C 4V is timed and curved to 14 degrees initial, 20 degrees on the crank for a total of 34 all in at 3000 rpm plus about 4-6 * on top from an adjustable vacuum canister.
I have not seen or looked at a PIII since, but I would hope that Pertronix have by now improved the design of the bearing. Electronically, I think it was a good piece, I liked the fact that one can change the rev limiter. While on the subject, you need a matching coil for the PIII AND a FULL 12 V for it to work.

Thanks, I have the voltage and coil so all good there.

 

[sabrie]

Quick update, I was able to get it close enough to get running and fine tuned from there. Thanks for the help all!!! Now on to brakes, windows and top.....

 

[mrgmhale]

While I have no experience with timing a 302, I do have BAD experience with the Pertronix Ignitor III. I'm not going into the full story, but back in 2012, my engine builder installed a P III in my engine. It proved to be nothing but problems. I eventually tracked the problem to the crappy way Pertronix constructed the PIII for the Ford distributor. Instead of using a bearing between the two plates, as is in the DuraSpark distributor, they chose to use a plastic "bearing", that wore out within weeks, causing the air gap to increase/decrease as well as the top plate could be seen to move upward. This was revealed on a distributor machine. This meant that the timing was moving all over the place. I sent this POS back to Pertronix and although they would not admit the problem, they did replace it with a PII and matching coil without question. That PII has been in my car since without any issues. My 351C 4V is timed and curved to 14 degrees initial, 20 degrees on the crank for a total of 34 all in at 3000 rpm plus about 4-6 * on top from an adjustable vacuum canister.
I have not seen or looked at a PIII since, but I would hope that Pertronix have by now improved the design of the bearing. Electronically, I think it was a good piece, I liked the fact that one can change the rev limiter. While on the subject, you need a matching coil for the PIII AND a FULL 12 V for it to work.

Stanglover, it is a bummer you had such a miserable experience with the Pertronix III effort. But, I get it. But, what impressed me is you actually found someone with an old distributor test machine (I am guessing an old Sun system), much less someone who knew how to operate it! Good job, all the way around! If I had the room to place one of those old school distributor testers in my garage I can assure you I would be all over it. In the right hands miracles can be worked with advance curves, ultra fine tuning, and some terrific diagnostics for unusual situations,

Until very recently I have been steering clear of aftermarket ignition system upgrades into pointless primary ignition systems. But, recently I was asked if I would be willing to help a fellow enthusiast in Brazil learn how to install a Pertronix system. He wanted to get the P1 (1281) Ignitor and a Flamethrower 1.5 ohm ignition coil from Pertronix. As I wanted to be able to help him out from a good point of reference I decided to get the same setup for our 73 302 2v Mustang, which has been running perfectly well with its oem point and condenser system.

Long story short, in preparation to do the installation I decided to check the baseline settings of the ignition system before doing the installation. I found our points were running at 42 degrees of dwell (where at 45 degrees they are totally closed). That happens when the rubbing block on the points wears down and the point begin to close up, which also retards the ignition timing. I had just reset the dwell angle to 30 degrees in Summer, 2022 - and in less than 200 miles of driving they were closing up again. I decided the Pertronix installation due to me wanting to help a fellow enthusiast was a fortunate occurrence.

The Pertronix (I), not P II) and Flamethrower coil are working fine. I did wire the Ignitor to run on full battery voltage, as well as the Flamethrower coil, per instructions. I am (so far) very pleased with my decision to do the installation, and look forward to many years of not needing to fuss with the points ever again (although I always enjoyed replacing them back in the day).

https://youtu.be/_qGVhoFnJ50

 

[Stanglover]

Stanglover, it is a bummer you had such a miserable experience with the Pertronix III effort. But, I get it. But, what impressed me is you actually found someone with an old distributor test machine (I am guessing an old Sun system), much less someone who knew how to operate it! Good job, all the way around! If I had the room to place one of those old school distributor testers in my garage I can assure you I would be all over it. In the right hands miracles can be worked with advance curves, ultra fine tuning, and some terrific diagnostics for unusual situations,

Thanks, The person who had the distributor machine was an engine builder who specialized in short track dirt oval race car engines, mostly Chevy, but he was also well accustomed to Ford motors. He had a 351C sitting on a stand that was already 'done' and I had asked about buying it. Unfortunately, Dave had some medical issues and when he suffered a heart attack, due to his religious beliefs, refused a transplant and died. The family apparently sold of all his stuff privately and I never got the chance to buy that motor. Also, no idea what happened to the distributor machine.
As for the Pertronix, I had no hesitation losing the points, way too much fiddling about for my patience. The P I does not have to be run at a full 12 V, but it doesn't hurt.
However, if I were in need of replacing the distributor again, I'd look seriously at a DuraSpark set up. My 'problem' with my Ford dist. was the fact that these were originally way to retarded, mainly due to emissions requirements coming in to force. 6 degrees initial timing is not optimal. After much research and help from my brothers here, I rebuilt the dist. by welding part of the limit slot (15L) and recutting it to match a 10L which reduced the crank degrees to 20. That way I was able to increase the initial timing to 14-16. I found 14 to be optimal for MY motor. I'll not expand further here, but with spring tweaks and some other carb tweaks, I'm very happy with the way it runs.

 

[mrgmhale]

Thanks, The person who had the distributor machine was an engine builder who specialized in short track dirt oval race car engines, mostly Chevy, but he was also well accustomed to Ford motors. He had a 351C sitting on a stand that was already 'done' and I had asked about buying it. Unfortunately, Dave had some medical issues and when he suffered a heart attack, due to his religious beliefs, refused a transplant and died. The family apparently sold of all his stuff privately and I never got the chance to buy that motor. Also, no idea what happened to the distributor machine.
As for the Pertronix, I had no hesitation losing the points, way too much fiddling about for my patience. The P I does not have to be run at a full 12 V, but it doesn't hurt.
However, if I were in need of replacing the distributor again, I'd look seriously at a DuraSpark set up. My 'problem' with my Ford dist. was the fact that these were originally way to retarded, mainly due to emissions requirements coming in to force. 6 degrees initial timing is not optimal. After much research and help from my brothers here, I rebuilt the dist. by welding part of the limit slot (15L) and recutting it to match a 10L which reduced the crank degrees to 20. That way I was able to increase the initial timing to 14-16. I found 14 to be optimal for MY motor. I'll not expand further here, but with spring tweaks and some other carb tweaks, I'm very happy with the way it runs.

I agree the 73 engines were one of the earlier versions of "smog control engines." Lets see, lower engine compression, valve timing slightly retarded, dual diaphragm vacuum advance diaphragms in some of the engines, EGR Valves, AutoTransmission dual modulator diaphragms... That is a bad enough start.

But, they are still really nice looking cars, despite the energy absorbing bumpers that began that year. And, since we are not subjected to emission system testing in NY due to the age, we can do what we want (within limits) with very low risk of being slapped with a fine or other punishment. And, there are still a lot of high performance parts out there for these vintage pony cars!































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