302 Manual Adjusting Timing after Replacing Points

[tonytony9]

I just replaced the points and am learning how to properly set base and total timing. I did not remove my distributer when changing the points and used a feeler gauge to gap, I believe it was about .021. Since my dwell changed as a result I would assume timing will be a bit off from before. I am utilizing a dual port distributer vacuum advance (just replaced and I believe it is working correctly as the engine idle drops when I plug the top vacuum advance port). My vacuum lines are set-up true to stock for a 1970 (August 1969, New York DSO). I have an original, Autolite 2100 2b just rebuilt.

I purchased an Innova digital timing gun with tach.

Can someone please, in layman terms, provide me the step by step instructions to set my timing. I have very solid compression for my stock/original 302. I know base timing without advance should be about 6-8 degrees as a start for base.

This is how I am going about it. Am I doing everything correctly?:

1. Connect timing gun to battery & 1 cylinder spark plug wire (passenger side, first one).
2. Start Bronco and let it warm to operating temperature. Double tap to step down to idle to normal idle. I believe idle for a 303 manual transmission should be about 650 rpm.
3. Remove both vacuum lines from the vacuum advance (top port and front port) and plug both.
4. Point timing gun at the balancer. My balance is quite rusted, its hard to read. My mechanic put a white line, I believe he said that should mark about 8-12 degrees BTDC. If i need to advance or retard, loosen distributer screw and turns while engine is running clock (advance) or counter clock wise (retard)
5. Reconnect vacuum lines, hold idle on carb in the 3000-3500 RPM range. Advance should be in the mid 30s range.

Here is my issue, on my timing gun, the white line on my balancer and pointer on the block line up when I set my timing gun to 16 degrees. This is with the vacuum advance plugged (both tubes or even just one at a time), and with the vacuum advance hooked up). The degrees advanced does not change just the idle (decreases) when I plug the advance. My base idle based on the timing gun (my only tach) seems high, I believe between mid 800's and mid 900's depending on if advance is plugged.

Should I adjust my idle down on the carb before retarding my timing (by adjusting the distributer screw) to get a more accurate read on the base timing degrees? Do I plug the top, front or both vacuum lines on the advance? Will I hurt the engine by driving temporarily as is? I really need the Bronco this week. I have taken for a couple of rides and it seems to be running smoothly. I dont believe I have any knock, which would make sense since my timing seems low. Uploaded a video for visuals.

Video Link

Thank you!

 

[Torkman66]

Couple questions:
1. Where is your vac advanced connected to draw vacuum. If direct to manifold then no problem, if ported through carb then you only get advance when carb idel is raised to ported rpm.
2. You will want about 32 degrees all in at around 3400 rpm. With everything connected (vac lines) what is the max timing you see?

The timing stops advancing at around 3400-3400. With everything connected you have 3 timing inputs: initial setting, mechanical inside the dizzy, and vac from the engine. All three is consider "all in" advance and should be about 32. max.

I always start around 10 on initial timing with vac disconnected and plugged.
Then reconnect and run up rpm to around 3400 and check advance (this is you all in timing).
If it is 34, then back off initial timing 2 degrees.
If it is 30, then advance timing 2 degrees.
You are shooting for 32 all in.

Old school is to grab your dizzy timing wrench and go drive somewhere that has an incline hill. Advance the ting until you start hearing what sounds like pebbles rattling in a tin can when accelerating, AT that point, back it off just enought to stop the rattling sound. Go home and check the at idel timing (vac disconnected). That is where you engine runs the best and is used for you future reference.

I have used the induction method (first description going to all in) and then followed it by the hill test run. Sometimes I get a rattle can and need to back off timing a bit.

Finally, you can allso time an engine by vacuum pull from the manifold. Hook up you vacuum gauge and set timing to the initial place that provides best vac.

I always use method 1 (all in). It is really the only method that takes into account all three timing operations (initial setting, vac advance, mechanical advance).

 

[ntsqd]

Keep in mind what Smokey Yunick said about timing a very long time ago:
"Two degrees too little timing is no big deal. Two degrees too much timing is a big deal." Or words to that effect.

I would start by verifying that the mark on the balancer vs. the pointer being used is truly at TDC.

There is a way to set the timing without a timing light and have it be spot-on. ACVW guys have been doing it that way for decades, but I'll leave out how until asked for it so as to not cause confusion.

 

[Broncobowsher]

I took some notes when I was converting my 460 to computer controlled timing with a Sniper.
Initial timing was 15°, which I though was a bit much for an emissions era engine. But low compression and big bore, makes sense.
Centrifugal was another 15°, forgot when it was all in. But that gave 30° of total advance. That sounds correct for an emissions era engine in a truck application.
Next up I ran the vacuum advance. It was 15° as well. Which if you are at that much RPM to get full centrifugal advance and enough vacuum to pull full advance, you will need that spark 45° advanced so maybe it will have enough time to propagate in the lack of cylinder pressure.

As my old tuner once stated about timing, as little as possible without affecting power, providing you are not dealing with detonation.

Often people will try for a little more total timing to try and make a little more power. Ignore the correct way is to change the travel of the weights in the distributor because that involves work and parts to do it right. So they will just crank up the initial timing extra high. Now they are sacrificing idle and low speed driving where they spend 98% of there time for a little bit of perceived power on the top end. Fine if you are playing around at the dragstrip for the day, not great for general driving around. I've fixed a lot of amateur tune ups by removing a lot of timing.

 

[B RON CO]

Hi, the dual vacuum canister from the emission era will only work properly if you have the control valve and the rest of the hoses and vacuum ports. You need to check a vacuum hose diagram. Post a picture of the thermostat area. Many times some or all of the parts are missing or not hooked up correctly. Many guys will eliminate the inner vacuum hose, which retards the distributor, and only use the outer hose, connected to ported vacuum on the carb, like the earlier engines. These engines will run better with more initial advance then what Ford specifies, @ 10*-12* usually works out pretty well, but as mentioned, more initial timing is fine, as long as the engine doesn't ping under load. Get the ignition system tuned, and then do the final carb adjustment. Good luck