How do I time this thing?

[sabrie]

Just got my `73 302 running again! Added a petronix 3 to the distributor, re-installed and got the timing close enought to start. Went to try and set the timing with the gun and realized I can't even see the balancer. Is there some magic I need to know to be able to set the timing with a timing light?

 

[Paul M]

My Cleveland was tough to see. I had to really reach down at an angle. I didn't like the RPM readings from my electronic distributor to the timing light either, So I marked the balancer at 36 deg, used an old basic timing light and used total "all in" timing to set mine.

 

[Cleveland Crush]

Pretty much as Paul said.
I use White paint or "White Out" correction fluid and highlight the stationary pointer and the appropriate idle timing mark. Additionally highlight the appropriate total timing mark on the balancer (to check maximum timing). Depending on your distributor set-up, you may need to block vacuum hoses.
The photos are my timing marks (aftermarket balancer and pointer) but same basic procedure for factory set-up.

 

[giantpune]

I start by using a piston whistle in plug #1 hole to find the compression stroke. Then Use a piston stop in that hole to find true TDC. And verify that your timing pointer is actually correct. There are more than a few things that would cause the pointer to not point to the correct number.

Then I like to use a timing light with adjustable advance feature. Disconnect the vacuum advance line and plug it. Then aim the light at the balancer. There's a couple little gaps you can look through to see the timing pointer. Usually the stupid alternator blocks most of the view. But you can look in the gaps behind, beside, above, and in front of it. I think the biggest gap for me is usually shining the light in from above the water pump, favoring the passenger side and then I stand over near the battery, looking in past the front of the alternator.

The adjustable timing light is nice because you can set it to any arbitrary number you want. Even if you want a number like 7 or 18 degrees and you dont have marks for those on your balancer. You dial in that number on the light, then set the timing on the car so its firing when the pointer is at 0 degrees.

Then you hook back up the vacuum advance and make sure the timing number looks sane. And if you have an extra set of hands, you can rev it to 3k RPMs and double check how much advance the distributor weights are giving you.

 

[sabrie]

Will get out the wire brush and paint pen and see if I can make it happen. Thanks all and will update when I get a chance to give this a try.

 

[Cleveland Crush]

You may have better success marking the  balancer from below (on your back) and of course the pointer from the topside.

 

[Hemikiller]

Assuming you have a correct 70-up setup on the engine, this is what the timing pointer will look like.

 

[RIBS]

Mine had no timing guide…I have seen many variations…some had timing over around 2 o’clock, mine seems to be closer to 10/11. I have a small window looking down past alternator where I see my mark….who knows if it’s setup correct now….my 71 302 has an alignment mark with a metal circle, but the shop manual notes that’s for “ford test equipment “ I use the pointer…I mounted this using the same two bolts shown in Hemikillers picture….

 

[sabrie]

I was able to wire brush it enough to find the timings markings and was able to get a small window to sight the timing gun through so I think it is set now. Still has a big hesitation when stepping on the gas that I'll have to work through. Will work vacuum next and then start poking the carb. But at least I have timing set, thanks all!

 

[sabrie]

Assuming you have a correct 70-up setup on the engine, this is what the timing pointer will look like.


View attachment 75799

Just to make sure, the timing place to look for is the flat edge on the upper side of the pointer?

 

[Hemikiller]

Yes, you reference off the upper flat edge.

 

[giantpune]

Just to make sure, the timing place to look for is the flat edge on the upper side of the pointer?

yep.

 

[sabrie]

Also, what is the difference in distributor vacuum advance canisters? I was thinkng of replacing the old one while I was at it and i see there a few that look the same, but that the '73 calls for the VC135. i see amazon has the VC25 and VC31 that look the same, are they all usable or is there an actual difference?

Yes, you reference off the upper flat edge.

Thanks!

 

[Big Red Mach 1]

Still has a big hesitation when stepping on the gas that I'll have to work through.

Not hard to imagine that your idle speed screw might have been adjusted during this process. Check your adjustment at the accelerator pump before you start looking to replace anything. Every time you play with the idle speed screw, your adjustment between the spring and acc. pump arm changes. Sometimes it's the simple things we tend to overlook.

 

[70cobrascj]

Also make sure the outer ring of your 50 year old dampener isn't loose and moving every time you try to time it. Ask me how I know

 

[mrgmhale]

Wow, this is one of those trip wire kinds of posts where a question asked ends up opening a can of worms (not a bad thing at all). And, of course I am eager to share some of my thoughts. I see a few things of interest, where they have been addressed to one degree or another, but to make sure no stone is left unturned I will likely end up covering topics already addressed (apologies in advance).

I am constantly fearful of coming across a harmonic balancer whose outer ring, with the engine timing marks on it, has slipped. That will result in incorrect timing settings. In cases like that I have a way of performing a dynamic timing adjustment that has served me well over the years. I will cover that below.
I use a white touchup paint brush while under a vehicle to mark the 0 degree and 10 degree marks on the harmonic balancer. I use a remote crank button to tap the starter a little at a time until the timing marks on the balancer are clearly visible to me. I use a fine white line across the entire width of the balancer at the 0 degree mark, and a half width line for 10 degrees. Sometimes I also mark the 6 degree mark with a slightly less wide line also, for an engine with a 6 degree BTDC spec. Then on the timing marker plate, above the balancer, I use a very fine white touchup paint line at the flat edge, where the timing marks on the balanced are measured against. It does take some time to do all that, but once it is done, it is done. The time I take to do that one time is more than made up in trying to find and see the timing marks. Even as a technician I would use white touchup paint for customer cars to make it easier for me to see their timing marks.
When working on the ignition timing I also take the time to use a vacuum tester to make certain the distributor vacuum advance diaphragm is n0t leaking or ruptured. I also put a vacuum gauge on the vacuum hoe feeding the vacuum advance diaphragm and crack the carb throttle blades enough to verify the diaphragm is getting ported vacuum. I also remove the distributor cap and move the rotor clockwise and counter-clockwise to make certain the mechanical advance system is not frozen up, and that I get the "springiness" from the mechanical advance control springs expected. It is nothing precise, just a quick check to make certain the mechanical advance will work when the engine is running.
There is mention of hesitation (on acceleration). That can definitely be caused by retarded timing. But it can also be caused by inadequate or missing vacuum advance due to a non-working vacuum advance diaphragm. In some cases replace diaphragms have Allen Key headed tension adjustment screw access by putting a small Allen Key (I am pretty sure 1/8 inch) into the vacuum canister inlet and turning the screw in one direction to increase the spring tension, and the other to loosen spring tension. I have come across cars where "someone" previously set the tension screw to its highest level of tension, thus keeping the diaphragm from being able to provide enough vacuum advance on light acceleration, resulting in a doggy level of low end, off idle, light load performance. I liked to set the tension as light as I could without causing light load pinging. Some other thoughts include:

• I have seen hesitation caused when a fuel float level is too low. The symptoms are hesitation on acceleration, and loss of power on turns. I found this on our 73 Mustang's 302 2v, where despite very low miles (barn stored over 40 years), "someone" apparently rebuilt the carburetor. Whoever rebuilt it made two mistakes. First the float level was 1/4" too low, a huge misadjustment, and I am surmising that person felt that would somehow improve fuel economy by leaning out the A/F mixture. Second the Passenger Right mounting stud nut was loose, and I could tell by the base gasket impression not having "witness impressions" that corner of the carb at the base had a vacuum leak. RThe leak was not enough to cause any large problems, but it was there. The float setting being 1/4" too low, however, caused light throttle hesitation, but surprisingly it did not cause power loss when cornering.
• Hesitation can also be caused by a carburetor accelerator pump not getting adequate fuel squirted down the main venturi(s) when the throttle is opened. That could be due to a fuel accelerator pump cup seal (1100 1v carbs) leaking internally, an improperly assembled carburetor where the accelerator pump channeling has a part that is missing or damaged. A too common example is on an Autolite 2100/2150 2v carb that is missing the "drop weight rod" on top of the check ball at the bottom of the accelerator pump discharge well. It can also be due to misadjusted linkage. I had a fairly new 1978 Mercury Zephyr with a 302 2v engine with a horrible hesitation on acceleration. I looked down the venturis when opening the throttle and saw only one of the two accelerator pump discharge nozzles squirting fluid. I removed the discharge nozzle and found a piece of brass drilling scrap that was blocking gasoline from going out a blocked nozzle. I used a jeweler's pin vise and very small diameter drill bit to redrill the nozzle, and the engine then performed perfectly. On some Holley carburetors I have had to replace the standard 35cc accelerator pump cap with a larger 50cc accelerator pump cap, as well as use a mre aggressive pump cam to activate the pump lever. In 2100/2150 carbs, pretty much all such carbs can have their accelerator pump pump linkage set up to use a linkage rod hole closer to the pivot point of the pump actuating arm to get a larger fuel discharge. I have never had to do that on a 2100/2150 carb, and would hesitate to do so as it introduces a consistently, and constant, increase if fuel use any time the throttle is opened - which will have an adverse impact on fuel mileage especially in in-town driving where the throttle is always being opened and closed. But, for anyone who is really in need of some heavy duty pump action that is something available to harness (again, not recommended).
• In 1973 Ford began to use Exhaust Gas Recirculation (EGR) Valves to introduce some inert (already burned) exhaust gas into the intake manifolds in an effort to reduce combustion chamber temperatures/pressure, thereby reducing NOx emissions. It was an effective solution, but it could also cause problems if the EGR Valve got its ported vacuum signal too soon or too strongly, and the EGR valve opened too soon or too far. Either situation can cause a hesitation. To test to see if the EGR is causing the hesitation you can simply unplug the ported vacuum line that connects to the EGR valve, be sure to plug the end of that vacuum hose, as often the same ported vacuum that also provides ported vacuum to the distributor vacuum advance diaphragm. In those cases where Ported Vacuum activates both EGR and vacuum advance movement, leaving the EGR vacuum hose unplugged causes a vacuum leak in the ported vacuum line, and the vacuum advance diaphragm actions will be adversely impacted.

Coming up, how I dynamically adjust ignition timing on old school engines...

 

[mrgmhale]

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.

 

[Stevieray]

How old is your dampener? I never trust vintage unless it is newly rebuilt. Damper Doctor in CA does a fantastic job. They did both my b1 and b2. Prior to the rebuilds, I always timed by vacuum. Jon with Pony Carburetor’s put out a step by step method. Solved a lot of my issues following carb rebuilds.

 

[Ciphyx]

Just a thought, you said you have an igniter 3 distributor? I contacted pertronix about mine and they said I needed a timing light that could read multispark. This did make a big difference at least from what I saw on mine. Not sure if you’re using a multispark ignition, but it’s an issue I ran into according to the manufacturer.

 

[Stanglover]

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.