302 Engine Timing (theory and practice) - Ford Mustang Forum
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post #1 of 21 (permalink) Old 12-03-2019 Thread Starter
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302 Engine Timing (theory and practice)

As a fellow vintage MUSTANG-ER, I wanted to share this conversation I had with a professional engine builder as I thought is was helpful for me and maybe would be for any of you out there. Feel free to chime in with your own ideas/comments or just take in the knowledge. Cheers!



First my set-up description and my question following:
1968 Mustang Fastback

Eng: SBF 302 (1968 cast)

Pistons: KB Performance Series

Cam: Comp XE-268-H - 1600-5800 XE 224/230 Hyd Flat
High energy Roller Rocker kit to accompany Comp Cam.

Manf: Edel Perfomer RPM

Cast heads: professionally ported and polished

Dist: Pertronix D7130700 billet, has vacuum advance 14* standard I THINK?.. not sure if adjustable, never looked.

Carb: QuickFuel 450 cfm HotRod series 4bbl Dbl-P

Idles: 850 rpm regardless of timing.. slightly rough idle very lopey characteristic of that cam.

Vacuum: 10Hg 1-1/2 turns out on 4x corners: 13.5 - 14.0 AFR | Cruise: 14-16 AFR | WOT: 11.5-13.5 AFR

Compression:
9:

Fuel: Premuium 91-octane

Trans: 4-Speed wide ratio, with 3.40 posi rear 245-50R-16s


QUESTION:

Timing: I've tried everything... but I'm not sure what is best for this set up... ???
What I've tried below:
A. initial 12 /mech 24 (rough idle, snappy throttle, but weaker low end until past 3K

B. 12 / 20 / 14 (snappy throttle, rough idle) accel okay. (so far I think like best but haven't tried a couple more combos)

C. 15 / 20 / 14 (smoothest idle of all, best manifold vacuum, bland accel)

Putting initial up to 15* smoothed idle, and had to readjust my idle down to 850 from 900. Total was 31/32 even though I used 20* mech limiters.

Not sure how I'm losing a few degrees? I used a new timing light that has dial back and RPM. I'm wondering if my pertronix limiters are not limiting correctly and giving me 18*
Do I go more on initial? Is my cam capable of more initial & still benefit with a 224/230 duration?

Maybe I'm just asking too much for my set up... I'm just trying to create best performance with out messing up my engine.

(I plan on trying 18 int. / 16 mech for a total of 34* and use my silver spings to be all in at at about 2600rpm. Based on Arron's suggestion after speaking with him. I haven't had time to do this yet, but will and will leave a comment on what the results are.)


Arron from BAD-ASS-CARS helped answer my question and give me some ideas of what he would do to improve the performance.

Here is his suggestion I wanted to share with all of you..

Every engine is different but almost all of them on the street like 36 degrees of total timing. You can't look at your vacuum advance other than part throttle driving. It ain't working at WOT anyway, nor at an idle UNLESS it's hooked up to manifold vacuum, which in your case it should NOT be. Now, because you are running KB pistons, they are hypereutectics which are still cast and are a bit "brittle". KB says to not run more than 34 degrees of total timing to avoid piston damage. I've run hundreds of sets of them over the years.

Looking at your numbers, I don't see what the problem you are trying to solve is. You have a cam that is not going to, nor is designed to, idle smoothly, especially in a little 302. The more cubes, the less the cam affects the idle, so with only 302 cubes, a 224/230 cam with probably a 110 LSA is going to idle rougher than it would if that same profile cam was in a 460. I would have gone with something that had more like 214 / 224 on a 112 LSA or something for a little 302 so it could "pull" through the RPM range, but I can't say that Ii haven't ran cams with WAY more than that, BUT in quite radical engines and cars that were completely set-up to by in sync with such a set-up.

You said in one of your combos below that it idles rough but pulled OK, so what else are you looking for? If you want a smoother idle, change the cam to one with less overlap and a wider LSA... it'll idle smoother. It'll also pull harder at lower RPMs because it would make more torque. The cam you have right now is never going to make any decent bottom-end torque, especially if you don't have the gearing to accommodate it, which with that set-up should be at bare minimum 3.55s and more like in the 3.73, 3.80s area. If you have taller gears, it's going to pull like a slug below about 3,500 RPM with a little 302 like that. Like trying to take off from a dead stop on a10 speed when it's in 5th gear. I don't care if you're Hulk Hogan, you are not going to be doing any jack rabbit starts until or unless it's in 1st or 2nd gear first. 302s are not torque makers with their little 3" stroke, and even when you do have some good torque, you still need the gearing to go with it or you end up like Hulk Hogan on that 10 speed in the wrong gear. A 10 year old girl on a bike in 1st gear would wipe the butt with the road from a dead stop up until she ran out of leg RPM.

Firstly, I'd stop using your vacuum advance. They were designed for stock engines to increase part throttle economy when cruising down the highway, not for performance use. Again, they don't work at WOT, nor at an idle anyway, which looking at what you've said, seems to be your concern.

You can run as much initial as you want as long as you don't exceed 34 degrees total, (KB's recommended total), BUT once you get up to the 28 degrees and-on area of initial, your engine will surge when running down the road at part throttle until you step on the gas where it will smooth out again. Your cam has zero to do with ignition timing or how much it can handle. 34 degrees is 34 degrees regardless of what the cam profile is. I prefer to see about 20 - 24 on the crank and maybe 10 - 14 of mechanical in the distributor. That ensures you get the most out of your initial timing for a snappy engine and high idle vacuum signal, yet still enough of mechanical to allow it to "idle down" and not "surge" when cruising at part throttle down the highway.

I have a great article on timing at this link
https://www.badasscars.com/index.cfm...prod/prd76.htm

and a couple of videos you should watch at these links
https://www.badasscars.com/index.cfm...rod/prd447.htm
https://www.badasscars.com/index.cfm...rod/prd451.htm

Some of the info on re-curving a distributor and on how a vacuum advance works you will already know BUT there will be some additional info in there that you probably didn't know, and that is the info you could probably use. Just don't exceed 36 degrees of total timing (excluding your vacuum advance) and you won't hurt your engine. All you'll do is change how it idles a bit, it's throttle response, it's idle vacuum signal, and how hard it'll pull below about 3,500 RPM. None of those will "hurt" or cause any damage to your engine. Too much timing will (detonation), and too little timing can (too much heat) if you don't pay attention to it.

I hope some of that helps.
Thanks!!
- Arron


Last edited by JTingle; 12-06-2019 at 07:14 PM.
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post #2 of 21 (permalink) Old 12-03-2019
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Use whatever works best for you and your driving style. Remember you cannot ask someone else what will work best for you, you must find that for yourself by trial and error.
Also keep in mind that no 2 engines are the same, they have too many moving parts, spaces and variables. Even 2 of the same block, head cam, etc right down the line will not be the same when all is said and done. When you look at 2 engines at the molecular level, there are far more differences than similarities even in two "identically prepared" engines, and it is on this level that the engine interacts with the air and fuel it uses.

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post #3 of 21 (permalink) Old 12-03-2019
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Arron is right on all points, in regard to your engine. Except one. It is clear that he knows what he's talking about! But there are a couple things he's kind of skimming over. He's talking about setting up an engine for maximum peak power, which works well on a drag strip. For a car that is street driven however, there are a few things more you might want to know.

A street car needs to be concerned with good *average* power, not just high peak power. That way, no matter how fast you're going, when you step on the gas, your car immediately responds. It won't sluggishly build RPMs till it hits its "sweet spot" on the top end. Drag cars don't give a rip about low end or midrange. They just put steep (big number) gears in the back so they don't have to sit at low RPMs. Having a high peak is by far the most important consideration for a drag car, not how it behaves when you punch the throttle trying to pass someone from your cruise speed.

He's absolutely right about your cam. And with a big hairy cam, it's mighty hard to make vac advance work properly. A lot of racers just consider vacuum advance a waste of time and effort.

However, with a cam that does not have so much overlap, vacuum advance lets you set your mechanical timing (centrifugal only) to numbers that work very well with wide open throttle, and then at closed-throttle operation, it adds more timing to help the very thin air/fuel mix light off earlier. High manifold vacuum means very little air and fuel going in the cylinders, and that lights slowly. Running without vacuum advance means that in real-world driving conditions, your engine is going to be a compromise. Turn down the timing far enough that it doesn't ping at cruise, and it'll be sad and sluggish. Turn it up high enough to give you crisp performance, and you have problems with ping, dieseling, and very high cylinder temps as you're trying to cruise down the highway.

Vacuum advance 'tunes' your engine as you drive. It adjusts for mixture density in a way that simple mechanical advance can't. A lot of racers say that you 'don't gain any power with vacuum advance'. And it's true - if you are only talking about peak horsepower. Because even if you HAVE vacuum advance, the moment you step on the gas pedal and have little or no vacuum in the manifold, you aren't using vacuum advance anyway! Your mechanical advance is the baseline for 'wide open throttle'.

But during any part-throttle situation, vacuum advance makes your engine more responsive, prevents stumbles and hesitation, gives you more power from every tiny drop of gasoline as you're going down the road, and cleans up your idle too. Better mileage, better overall power, and far better longevity - because your engine doesn't have to compromise its tune for part throttle operation.

The only part I disagree with him on is idle quality. Vac advance can very much affect your idle quality, in a positive way. On anything but the meanest cams, it lets ignition light the mix early enough to reach peak pressure when it needs to. Without it, at idle, the mix burns so slowly, a lot of the fuel is still burning when the exhaust valve opens, causing a rough idle and high exhaust temps. However, when a cam with a lot of overlap (like yours) tries to idle, it isn't going to pull much manifold vacuum. Worse, it's going to have some lope, with the idle surging up and down a bit, changing the amount of vacuum in the manifold. If you try to tune your vacuum advance to work with that, it's going to be surging your timing up and down as your cam's lopey idle pulls more or less manifold vacuum. It's a nightmare. To try and help with that, in your special situation, you might want to use ported (sometimes called 'timed') vacuum. Ported vacuum is 'off' when your throttle blades are closed. But once you step on the gas, it delivers vacuum to the distributor. It is a bit of a compromise, but then, everything about driving a car with a big hairy cam on the street is a compromise.

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post #4 of 21 (permalink) Old 12-03-2019
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I agree with the suggestions that Aaron made and your 18* initial with 16 mechanical will help your idle with hopefully no detonation. Run 93 octane if its available in your area. I would not even connect your vacuum advance until you get your initial and mechanical sorted out. There are many articles on how to performance tune your distributor on a V8 engine, the numbers are generally in the same range as suggested in your post. The reason for this is simple math. Its not the 34* total that matters its detonation, which sometimes is not audible. Detonation can be somewhat silent and kill your pistons which is why the manufacturer suggests 34* or below. You want to keep your total mechanical timing + vacuum at 50* or below. I try to keep my total at 44-46* if I run vacuum and its always hooked to manifold. It helps the engine run cooler at idle and smooths the idle a bit.
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post #5 of 21 (permalink) Old 12-04-2019
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You may find better performance by NOT running 91 octane. Over my 54 years of running small block Fords "I" have found on many occasions that "premium" fuel in a low compression engine hurts power. A perfect example is my current 408W. It has aluminum Ford racing heads , 9.7-1 and an "X" Ford racing hyd roller. I ran it at our local 1/8th mile strip with the 87 octane ARCO I dyno'd it on and ran 12.40s ( 3700 lbs with C4 and 4.30 gear). The next week I tried 91 figuring I was potentially abusing it on 87. Slowed up to 12.50s and "felt" different. two weeks later on 87 ran back in the 12.40s.
With your compression at 9-1 and cam like you have the dynamic compression is low enough to use the 87 IMHO.
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post #6 of 21 (permalink) Old 12-06-2019 Thread Starter
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Thanks for your responses!!!

I appreciate all of you taking the time to respond.
I do have a another theoretical question that I'm having a hard time figuring out.
I don't plane on removing my vac advance.. I need it for my cruise down freeway on weekends...
I completely know and understand that each engine is different, and each set up is individualized to that engine, but knowledge is key over all in understanding why "my" engine will work better or worse with certain adjustments. My past set up has been 12 initial, 24 mech and what ever the vac throws in on travel.
I can easily use vacuum gauge and dial in my idle to run around the 14 AFR range and have snappy response.. My problem, like 07redstang mentioned is that detention can be a silent killer and you'll never hear the ping... upon inspection of plugs.. a few have VERY LITTLE peppering.. this led be to believe that I was getting an occasional detonation.. While driving I would get a sputter or bog on acceleration not thinking is was dentonation but just an adjustment I hadn't worked out yet. As I kept on the pedal the sputter would go away and acceleration would clean up. This was NOT a lean bog... as my AFR guage would show that punching throttle would dip into the 9:1 range... TOO RICH and as it would use up the fuel from the squirt, it would move back toward the normal side of 11-12s and smooth out which is what my timing was accommodating. My theory is that I had too much advance for that burst of richness and for that sec or two of acceleration it would ignite sooner and detonate. I've since corrected the "too rich squirt" with smaller squirters and now it dips to 11s and sputter is now gone on WOT punch and runs back up to 13s AFR.

So why change anything...? I'm exploring the tuning world for what's best and learning form it. I do know that more initial closes my butterflies up more, and gave at least a 1/2 Hg more vacuum that made idle smoother. So I figured if that was good, that I'd try to figure where to go from that base on my tuning... IF it doesn't work, I'll just go back to old reliable 12/24/VAC setting.


So the Question is for any of you science based or technical guys out there.. :-)

Let's say I set my timing to 18*/20* initial timing with timing light, not vac attached or course... I have my mechanical advance limiters in at 16* or maybe even 12*.. so my total Centrifugal advance at WOT is 34*/36*... For my set up I'm going to set my total to 34* total. So 18*/16*/ (?Hg)vac.
I have a Pertronix dist.. originally it was a II and I installed the III RPM limiter and flamethrower canister to make it more current. I like the rpm limiter because of my low rpm range.. 5800 tops, and it flattens out at about 5500 anyway.

What I don't know and get varying answers to from Pertronix is what the vac advance pot is set at from factory and what it's specs are. At what Hg does it pull all in... how wide a range is it... 12Hg,14Hg, 16Hg's ????? I don't think mine is adjustable as I've placed an Allen Wrench in there and can't seem to get it to hook up for turning up or down... I hope I didn't poke a hole in the diaphragm. I do know it works though as after I set the timing and plug in the vac, and rev I get higher than my total mech. setting.. It's in the 47-s-ish.. I have a dial back light and the zero mark moves back and forth ever so slightly.. prob do to my hand trying to hold it steady.. I hate being that close to the engine at a steady 4000 RPM and two hands in the engine bay.

The springs I'm running are the lightest-(copper) and the med (silver.. not the heavy...) I'm thinking of making them both med silver only because with the limiters silver will still allow for mech advance to be all in at around 2800rpm. Eliminating the copper with because of setting the engine with 18* initial and having light springs may induce too much advance too soon when taking off prior to getting blades open enough to drop vac in manifold.

I've read about using manifold port vac vs timed port vac, but I think definitely for my set up having high initial, I would NOT want manifold port vac. I think it would put too much timing in at idle and just off idle.
So to reiterate, can I get too much advance with a high initial timing setting and vac advance hooked up. obviously not on idle, but tip in and and part throttle driving?
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post #7 of 21 (permalink) Old 12-06-2019
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In a word, yes. You can have too much initial + vac advance. When you set your mechanical (initial) advance, you are doing it with vacuum disconnected, so you can see an actual value instead of something moving around due to the vacuum in your intake changing the timing. But what does that value mean? Should you set it to the smoothest idle you can get, with best manifold vacuum?

No.

Because what you are doing, setting your initial mechanical timing, is creating your baseline for Wide Open Throttle with your car in gear. Obviously, it would be very challenging to have your car idling at 600 RPM in gear with the butterflies wide open to see if it pings. So instead, you set it to a value that you believe is going to work. Typically no more than about 12 degrees for a street car with a typical cam. Setting that initial timing has nothing to do with how smooth your car's going to idle. It also has nothing to do with your idle bleed screws on the carb, because you need to hook up the vacuum advance first, to smooth things out. THEN set for best manifold vacuum/smoothest idle, with the advance kicking in. Your car may be idling around 24 degrees, with the vacuum advance hooked up too.

But just as important as all of this, is your *total* mechanical advance. Not all distributors will move the same number of degrees, on mechanical advance. It's adjustable. The exact method for changing it is different for every distributor. So no matter what you set your initial timing to, you need to make sure your total mechanical advance does not exceed 38 degrees. More realistically, a typical build likes around 34. For heads that have very fast burn characteristics like the GT40P, you would only want about 28 degrees. So if your total timing puts your initial timing too low (for example, 28 total, but your initial is about 4? Not gonna work very well.) you will have to look up how to adjust your distributor's advance to have less degrees of centrifugal advance. It often involves disassembly, and messing around with the plates under the springs.

As to why 'every engine is different', it's because people use a lot of parts combos. The carburetor you use, cam, compression ratio, heads, pistons, - even the air filter itself can change the burn characteristics of your engine. So, you must tune your distributor to get the engine what it wants.

Once you get everything set up the way it should be, THEN you go out and test drive, or put it on a dyno. A dyno will only tell you how your engine is running at wide open throttle, but it can help you tune for best power. Driving around in town, at part-throttle operation will tell you the rest about how well you did. Theory only gets you so far. It should at least get you in the neighborhood. You will have to learn to adjust your engine's timing and carburetor settings on your own by actually driving, to get it the rest of the way.


Edit: I keep forgetting about that lopey cam of yours. You have a special case. It's not an ideal combo for street use. If you use manifold vacuum, you're going to lose all your hair trying to make it work right, with your cam's lope, and the low manifold pressure. So with YOUR car, unlike most, I would recommend you use ported vacuum (meaning you have zero vac advance at idle), and yes, dial it up a bit. Maybe even 16 degrees or so, to try and help with idle quality. You will also probably want to work with your vacuum advance unit to limit the total number of vac advance degrees to maybe 6 or 8, so that when you are at cruise, you're not too badly over-advanced when the vac can on your dizzy kicks in. At 2k+ RPMs, your engine has the weight of the car and more RPMs to produce inertia, so the engine won't be bucking and surging like it tries to do at idle, allowing you to use a bit of vac advance.

Because of your cam's nature, there's just no way to make your engine produce good vacuum at low RPMs, and deliver a clean smooth idle. Manifold vacuum is not going to be your friend, for trying to make that work. You just don't have the option of letting your vacuum advance help you adjust your idle timing, so it's only ever going to be a compromise. Your headers and engine bay are going to be hot if you have to idle for extended periods. At least you have a manual transmission, so it shouldn't be trying to die when you take off!

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Last edited by Grimbrand; 12-06-2019 at 06:16 PM.
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post #8 of 21 (permalink) Old 12-06-2019
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There is no real limit to the amount of advance you can run at idle other than the starter may not like it when the engine kicks back. It will have no negative effect to the engine as long as the total timing is the range the engine likes with no detonation. A lot of people lock their distributors and run no mechanical advance while still driving the cars on the street. Vacuum advance is not a performance device, it is there for fuel efficiency. It goes away at WOT and you can run the engine fine without it.

Most V8 engines no matter brand like similar numbers in timing. Depending on the engine and compression, total timing with vacuum can be as high as 60. Total mechanical advance without vacuum can run up into the 40's.

Trying to get every ounce of power out of the engine or every MPG is not a recommended exercise because there are sacrifices. Set your engine up for the intended use of the car.

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post #9 of 21 (permalink) Old 12-06-2019 Thread Starter
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I was about chime back in that I wasn't sure you understood what I was explaining, but then your "edited addition of text" popped up and "Ah... yeah, you get it my prob now".. It really is a compromise. The engine runs so much smoother at idle with the higher initial, but because of wanting to try and make vacuum work to it's fulliest, I will prob just drop it back down to 10 or 12 degrees... and run the no limiters on dist.. 10/24/VAC

I have the Pertronix dist. Model number D130700. Does anyone know specs off hand about that vacuum pot or if it can be replaced with another one that is adjustable? I've contacted Pertronix twice and still have not received an answer. Seems like a simple question.. I can't understand why they wouldn't list all the specs regarding their own dist. in a manual or online.


Grimbrand, thank you for conversing with me.. helps me sort things out to be able to bounce ideas off others. :-)
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post #10 of 21 (permalink) Old 12-06-2019 Thread Starter
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I know VAC goes away at WOT.. it doesn't go away when accelerating normally.. it goes up. If I have high initial setting, I accelerate not fast enough to even go above 2500 RPM or maybe 3000 at most, VAC advance will be engaged and high initial will be there along side which in turn "could" provide too much advance too soon..

I'm not trying to squeeze every ounce of power out of my car or I WOULD lock out my dist. What I'm trying to do is give my self a smooth idle with best vacuum at idle and not hinder my performance over all. All this of course follows that I'm not harming my engine in short or long run.


I am trying to set up the car for it's intended use. This is why I'm asking various questions and exploring ideas on the matter.


I sometimes drive to car shows which are about an hour of freeway driving 70 mph with 3.40 gears is about 3200 RPM constant.. AND sometimes I just drive around my part of town and punch it here and there for fun. So it makes sense to ME that I get the best of both worlds or at least as close as I can for my preference.
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That cam will like the higher initial to smooth out the idle. I'd run the 16 limiter and set initial to 18 for 34 total. Figure out your vacuum advance so that you get about 44-46 total with vacuum.

The easiest way to tell what the vacuum advance is pulling is to hook up a hand vacuum pump to the unit with the engine idling. Note what the timing is and start adding vacuum, note at what vacuum it starts to pull in and at what vacuum it stops and how much.
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Everyone always says "Vacuum advance is just for mileage" and that it doesn't "add power", but that's really a copout. I drove without it for many many years on my original '67 Cougar, using a dual point Accel unit from a 289 Hi-Po, so I can say with confidence that any car you drive on the street will greatly benefit from vac advance.


It does not change PEAK power, but it sure does help response, and part-throttle power. It makes a tremendous difference for idle and cruise, even if it's a massive PITA to try and figure out the best settings for a hairy cam. It also really sucks when you've got things set too high, so your car diesels after you get off a long highway cruise, and won't shut off. It's just not a reasonable expectation for even a really good engine builder to tinker with a snotty cam's idle timing settings (using vac advance) for a customer to make something like that 'perfect'. You could go round and round messing with air bleeds, idle RPM, and initial timing, finding many 'acceptable' solutions. They would probably just set it to something that works to get it out of the shop as quickly as possible. And let's face it, if the car idles okay, this setting is really not that critical. It's not going to put holes in pistons or cost you seconds in the 1/4 mile. But because you OWN your car, you can play with it and figure out what combo you like best for your driving style, which is really the whole point anyway.


Sure sounds like you understand what's going on, anyway, JTingle! Good luck and happy motoring!
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This may be a case were you put too much cam in the engine. I've done it myself, Wanting the big HP number and then lamenting the lack of smooth idle and street-ability.

What I have learned over the (many) years is that it's not HP that makes fun on the street, it is low end torque. There are basically three ways to go fast on public roads without breaking laws:
  • Pulling away from a stop light and getting in front of everyone else;
  • Accelerating from a ramp onto a highway;
  • A twisty road where the suggested speed is lower than the legal speed.

Regards to engines, we are talking about the first two. So a mild cam.

On mild cam engines I like to use 8 degrees initial and manifold vacuum should add in about 15-18. That will give a nice smooth idle. Idle AF should be close to stoichiometric (lean) and lean mixtures take longer to ignite.

Stomp on the throttle manifold vacuum goes to zero and your AF ratio should go down (rich). Rich mixtures ignite fast so the loss of vacuum advance works for you.

As engine speed increases the mechanical advance comes in. Increase spark advance with increased RPM because it takes less time for the piston to reach TDC.

Cruising down the highway you set up your carb or fuel injection for lean, to save fuel and reduce emissions. Manifold vacuum is high, so timing is advanced to allow time for the mixture to burn.

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It is possible to buy your way out of the entire ignition timing, and fuel mixture control issue.

Early this year I did a complete drive train replacement on my 65 mustang. I had about thirty years on the last drive train. It includes a 427W that is controlled by FiTech port injection. FiTech also controls the ignition. The ignition consists of a standard coil, and a distributor that is just a mag pickup and rotor, neither vacuum nor centrifugal advance. You set it up for max advance - 40 degrees or whatever - and FiTech delays the spark to take out whatever advance it doesn't want. And you get a small, flat screen read out that will give you more information than you will know what to do with.

I bolted it on, by-the-book, and drove the Hot Rod Power Tour, and went to the NSRA nationals; 12K miles. Ran like it knew what it was doing.

About $1500, or so, I forget. But well worth it.
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The modern method is great and all, but I love the whole vintage appeal of my car. I've intentionally kept naturally aspirated and basic for the love of the vehicles history as a Mustang.
Sure adding all the modern touches can be pretty cool sometimes with resto mod engine swaps and upgraded suspension the bring your car to superior road handling but to me, I'd just go out and buy a new car if I wanted that. I set my own standards to not ad anything to the car that was not available to it in the year that it was built. So yes I do have some upgrades, but all of these could have been done back then.

With that said, I'll keep working on the Carb and Timing just as they did back in the old days.

It's been raining here so much that I've had to constantly put off playing with the car. I was able to set up the Timing to initial 18*/34*Total.. It idles very smooth and transitions from stop to go very smoothly.. It did hiccup when I stomped on it which was weird, so I don't know why that happened.

I was looking at the accelerator pump cam and making sure everything was adjusted... I followed the rule from instructions to hold the accelerator to WOT with engine off and adjust the spring and bolt to allow .015 room for bottom out... the problem was after making that adjustment, once I release the throttle there is then too much play between pump and throttle... another stupid problem to work on and correct.

As for timing, my next test will be to put it at 10* initial and 24* mechanical and attach Vacuum to Manifold instead of ported. The will put my initial in the 18-20 range when idling and I will put on soft springs to let mechanical ramp up quickly upon acceleration.


After that test I make my decision to what is best and post my results.

Grimbrand likes this.
JTingle is offline  
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302 , engine , timing , tuning

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