Trying to time a performance FE. Challenging, when it should be so simple. Why? Because of a number of things, but a major factor is with the side-pipes, I can’t hear the engine “ping” or “knock”. Also, I don’t like revving the engine with no load past about 2000 rpm, so trying to map the rate of ignition advance and max advance isn’t easy. Wish I had a dist machine.

So here’s the long and overly detailed tale so far. And for those of you who want to accuse me of over-complicating things, fell free. I admit to it. LOL.
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So, I always ran at 10Deg initial. Due to the springs in my Mallory distributor, quite a bit of advance was already used up, so max wasn’t 10 plus the built-in 24Deg for a max of 34, it was only 26 Deg max. (Oh, no vacuum on this dist….a Mallory YL). I didn’t realize this at the time, because my first Mallory YL had different weights, springs etc and would give me 38 max with a 10 deg initial.
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OK, so here’s the complication. Unknown to me my harmonic balancer outer ring had slipped. Not sure for how long, or when, or if it were gradual, etc., but measuring it, it was 22 Deg out.
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So, now my timing measurements have to be corrected and comes out at 32Deg initial and 48 Deg max.
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And it ran fine. Cranking wasn’t even difficult.
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Late last summer, I thought I might try some different timing settings. First, I tried 6 Deg initial, which corrected is 26 initial and 42 advanced. Engine was silky smooth and it didn’t bark so badly.
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Then I made a BIG error. I next tried 15 Deg initial which corrected worked out to 37 Deg initial and 53 deg max. The engine was struggling at the higher rpms. By 4000 rpm, it defiantly didn’t enjoy itself. Finally a piston land broke and game over. Stupid me.
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So now I have the engine all back and working and a new balancer on (marks double checked and a paint mark put on the pulley, so that if the outer ring slips, the pulley mark will show the difference). But where to set the timing?
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I think it’s a pretty well accepted fact that 36-38 Deg max is the accepted range for an FE, but what about initial timing? A little research shows that for my Crane Fireball cam (which I think is 294 advertised and somewhere around 227 at 0.050”) an initial timing should be between 14 and 16 Deg BTDC. I hooked up a vacuum gauge to the intake and moved the distributor around a bit. Crappy idle until 14 in Hg (where initial timing was at 14), and fairly smooth at 16.5 in Hg (where initial timing was now at 16 Deg BTDC). So 16 was to be it.
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So, I set the distributor for 16 Deg initial and 38 Deg max. This included limiting the advance rate to 22 degrees. Not wanting to lose advance at idle, I removed the heavy spring (which doesn’t even start to work until higher in the advance range due to it’s purposely sloppy fit) and added a second very light spring. I set the max advance statically at 38 BTDC, then started engine and checked idle at 800 rpm. Bang on 16. Cool. Reved the engine a bit. Advance was late starting. Didn’t move from 16 Deg until about 1400 rpm.
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So, the test drive. Engine was a dog with a bog, delay, and then secondary opening. Never did that before, so I can assume carbs are not the issue. Only timing is different. Anyway, eventually, after getting to about 2000 rpm, it smoothed out and seemed fine after that….I think….
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So, back to Mallory factory curve. Without adjusting the dist, I took out that second light spring and put back the sloppy heavy one. Initial timing now jumped to 21 Deg. Did another test drive? The bog delay thing was much reduced, but still not acceptable. Higher up in revs, it seemed same as before.
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Going back over my data, best response seemed to be that 6 deg figure, corrected to 26 Deg BTDC. Should I now set my timing for 26 initial, and reduce the advance so that the limit of 38 is maintained? That seems to be the next step, but sure seems high for an initial advance number.

I would appreciate any thoughts or even where you set your timing on your engine. Thank-you.

Ps: Freightrain, I believe it was you that said, you use solely the light spring on your Mallory Dist and it works fine with your FE matched to a standard transmission (stick-shift in mine as well). Can you tell me what your initial and max advance numbers are?

 

Set one, replace the harmonic balancer. While it seems to be just a simple metal ring, its has been drilled in spots to balance it to your cranks needs, if its slipped, its out of balance. With this fixed, start at 6* BTDC and make youe starting ajd from there. If you cant hear it, find a hot rod shop with a rolling dyno, that can best help with any timeing issues and max your proformance settings

 

New Balancer is installed. No dyno available.....sigh.

A little more research and it seems I dismissed something important. Apparently, to find the proper intial advance, you start with a low setting and work your way up in say, 2 deg steps. While doing this monitor your manifold vacumm and rpm. At each step, re-adjust your mixture screws and idle stop screws to obtain max vacuum while maintaining the same idle rpm. Great improvements in vacuum are expected for a while, and then they taper off. Optimum initial advance is the timing just as the vacuum increase slows down (starts to taper off).

Then I set my dist plate to give me 38 Deg max with the dist at the preceding setting.

After that, it's spring rates to keep it from detonating down low...not sure how to tell that yet.

 

Might concider some quiet mufflers untill your finished with set up, you really need to hear these engines to make them right

 

Actually you should set max mechanical timing to 38°, no vacuum hooked up.

Then look at what initial timing is and use that number for future setting and checking of timing. For a performance engine that 38° should be all in by 3000 RPM in a heavy truck and 2500 in a light weight setup.

With 38° total and anywhere from 10° to 18° initial you should not have any pinging issues.

 

Yes, I have it at 38 max now. Will do some more idle tests, but 16 looks about right from preevious tests. Playing with the idle mixture should help with the idle as I suppose the mixture requirements change with the spark advance setting.

So, I'll be left with that bog/delay crap, even though I didn't have it before when my timing was very far advanced and I didn't know it.

I think I see now one of the reasons for a vacuum advance. Besides economy, it would help transition the spark advance when going from idle to full power.

Oh well...more tinkering today.

 

Did I mention teh engine runs hotter than before?

Anyway, I think I need a vacuum distributor. Seems to me when I had the timing too far advanced and it worked well would be the same as the proper tuning with a vacuum advance added.

At idle, I set it for say, 16Deg. It runs hot, manifold vacuum is adequate, but not peaked. Idle has just become barely acceptable. But this is probably the best spot for full power.

With no load and a vacuum unit, idle timing could be as much as say, 45 Deg, but may fall to the 16 if the vacuum drops when the throttle opens.

On a light car, I probably need something in-between if I don't have a vacuum unit. This may match up closely with where it was set before (when it worked fine).

I'll do some more tinkering, but in the long run, I think I'll try to find a distributor with a vacuum can that offers adjustability for centrifugal advance amount, centrifugal advance rate, vacuum advance adjust, and maybe vacuum advance rate and/or amount.