I would tune for regular in case you end up ina situation where you can not get supreme.

So first thing you should do get your advance all in under 3000 RPM this will maximize your horsepower output and in turn combustion efficiency. This will necessitate a spring change to lighter springs.
Then set the advance so you are just getting light pining on at wot on Regular. This will allow to you run regular if you have to, and allow you to run full bore with no issues on supreme.
Then you can adjust your total mech with bushings to give you an appropriate base timing.

As for you advance pull the one out of your dist take it with you to Napa AutoZone where ever and ask for one for a gm HEI distributor such as SMP VC242 for HEI or VC24A for points then you can compare it to yours.

 

Hahahahahahahahahaahahhahahahahaha

Your wife is way smarter than I originally thought, and judging by the accuracy of her analysis and curiosity, I'm now very nervous, as I believe she could find me with ease.

So I'm definitely not going to say where I'm from, although yesterday at the Snow Man Building Competition, which I came last in again, I could have sworn I saw a kangaroo.

I understand your information overload, but it will lighten up as you put your new theory into practice.

Anyway, a high five to you, and a high five to Mrs 78 Ford F150 460, for actually doing the first stage of the timing curve.

By the way, did you watch the MSD video in the dizzy link you posted up ?

It's nothing more than a sales advert for MSD, and they assume that the MSD parts don't need to be checked, and therefore don't say a word about checking the actual curve !!

I plotted your numbers into a graph, which I tried to copy and paste into here, without success, but I need to get some MSD numbers for a comparative curve anyway, so I'll try again later.

Now that you've driven at 14*, then down to 12*, then down to 10*, did you feel the difference in power whilst driving ? (Part of the learning)

If not, no worries, coz when the timing is eventually dialled in with the mojo gas, you will DEFINITELY feel a noticeable increase in power.

I like your logic with regard to getting 21'' vacuum.

Ok, while we are using your engine, as it runs right now, as a guinea pig to learn from, set you timing to 20*, with the vacuum advance disconnected and plugged, and see what your vacuum is.

Then try 25*.

Then put it back to 10*, and post up your observations.

Did you read the voltage at the coil yet ?

Do you need an adjustable vacuum advance cannister ?

Today's engine is about to change to tomorrow's engine which will make it yesterday's engine !

By all means continue your search for one, but do not buy it yet, as it may or may not be needed.

 

Nope ! I'm not clever enough to copy and paste pdfs or graphs onto here, so I've attached them instead.

Look at page 3 of the PDF and you'll see MSD's numbers.

I've used these numbers as the 'expected' numbers in the spreadsheet. I might be 1/2* or 1* out, but it's only a guideline.

The top section, yellow highlights, uses your numbers, and the corresponding graph to the right of it shows that your actual numbers are very close to the expected numbers.

Given the similarity, one can ascertain that the electronic ignition is doing its job, and so we can proceed with confidence. (Which is not always the case. )

I added numbers to reflect mathewq4b's suggestion.

We already know that you have access to supreme gas coz you said so when you said you use it in your 460, but, seeing as you are learning, and if you have the time and inclination, you could try it.

Here's what to do if you want to observe :

Swap one heavy spring with a light silver (medium) one, and this should give you all in by 3,000rpms as per the blue highlights in the lowest table shown in the spreadsheet.

Do not change your existing 10* - 28* timing, and do not bother with plotting a new curve.

Take a drive. You'll be back home within minutes !! LOL

Now that you've created a pinging bomb, you'll want to do something about it.

Set your timing to 6* and go out again. (4* might be needed to stop the pinging.)

Now do you feel the loss in power, whether it pings or not ?

Swap your heavy spring back in, and re-set the timing back to 10*. (Now we do nothing except wait for the supreme mojo)

Yes I know, I've ignored the vacuum advance for this little exercise.

That exercise will purely illustrate to you how ignition timing in association with octane and gas quality can make or break an engine's performance. You'll have a direct comparison in the near future.

I really hope that your ignition wire is the OE resistor wire and you're only seeing 12v at the coil.

 

On what evidence do you surmise that getting the total in by at least 3000RPM is going to cause it to ping? What exactly are you basing that on? This ought to be good....

 

Oh boy, oh boy, oh boy, I love competitions, so yeah, this ought to be good.

 

Oops, I'm so excited about this competition that I pressed the submit button too early.

I've never won a competition in my life, and even the one time that it was only me in the Snow Man Building Competition due to a blizzard preventing the other competitors attending, I still came last.

I know I'm going to win this one.

My Mum is busy making my favourite breakfast, scrambled eggs and snow on hash browns. Can't wait to see her face when I tell her I won a competition.

Ok, here's my answer : I'm using the evidence submitted here and there in this thread, from post 1 until one of the recent posts.

I know that's the right answer. I win !!!! Yeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee eeeeeeeeeee-haaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaw

 

It doesn't matter if the OP or 440 sixpack also post the correct answer coz I posted it first, so I win !!!!

Please post up confirmation that I won so that I can show my Mum in black and white.

She eats kinda slow, so it will be a while before I can come back.

I win !!

 

So you're saying timing has no effect on the amount of air or fuel an engine needs for peak efficiency. thanks for nothing Einstein.

Obviously you're a person seeking the respect on the internet you've never received in the real world. maybe I should feel sorry for you but I don't , GFYS you're neither informative or entertaining.

 

Timing has NO effect on the fuel-air ratio delivered by the carb. As YOU claimed it does. What about that is too complicated that for you to understand. And no idea where you get from "Timing has NO effect on the fuel-air ratio delivered by the carb" somehow means "timing has no effect on the amount of air or fuel an engine needs"... Like how thick do you have to be to make that jump.

It is clearly obvious you have no clue what a fuel-air ratio is or what actually affects it.. This is just too complicated for your limited knowledge to grasp. Not the first time that has happened either.

 

So in short you are 12 year old have no actual functional knowlege. gotcha...

 

I didn't get a chance to do anything on the Bronco tonight. I had to go out to my sister and brother-in-law's house and help finish tearing down their shed. Got it done so I should be able to get back to the testing tomorrow after work. Still need to test the coil and some other stuff you guys want me to do. Stay tuned....

 

So I just went to change one of the heavy springs for a light spring and when I took the cap off I discovered I already have 1 heavy spring and 1 light spring installed. I thought I ad 2 heavy springs like I do in my 460. I guess I assumed wrong. So I assume that changes the plan of attack? So all this pinging has been happening with 1 heavy spring and 1 light spring. What should I do now, set it up with 2 heavy springs; swap the light spring for a medium (blue) spring, or just wait until I can use all the gas and fill it up with supreme? Or should I order a vacuum advance canister?

I was going to test the voltage on the coil but I got to thinking....doesn't a MSD Blaster 2 coil put out tens of thousands of volts when it fires? I'll blow up my multi meter won't I?

 

No it does not change the process. Again you set up the mech advance THEN do the vac advance. The vac advance has NO bearing on what you do with the mech advance. The mech advance takes priority and the vac advance is made to work with the mech settings. You NEVER EVER adjust mech advance to accommodate the vac advance.

 

The ONLY reason we are 'playing' with the timing at the moment is to observe and learn, nothing else.

Dialling in the timing curve permanently will only be done when you have the premium gas.

To do it now permanently is a waste of time because the new gas will drastically change things !!

By the way, just for clarity, is the cheap gas currently in use, 87 octane, and is the premium gas you are going to start using, 93 octane ?

Nope ! Still no need to order a vacuum advance canister because you still don't know if you will need one or not.

So, leave the speed (springs) of the timing curve exactly as it is.

You didn't yet say if you felt a loss in power when dropping from 14* idle to 10*.

If you did, good.

If you did not, drop it to 6* and go for a drive, then put it back to 10*.

This is purely to illustrate the effect timing has on the power of the engine, and 'feeling' the loss of power whilst driving will give you practical experience (as opposed to just pure theory).

Ok, you thought you had two heavy springs, and plotting your numbers against the expected numbers provided by MSD illustrated that the curve was about right.

Now that you know it is in fact one heavy and one light spring, we can see that curve is way slower than expected, has an annoying drag between 1,000rpms and 2,000 rpms, and does not reach all in at 3,000rpms which it should.

(When your engine was set at 14* idle, was the pinging at partial throttle happening at +/- 2,000 rpms?)

Do you now fully understand the importance of plotting the timing curve ?




Sorry about the crap quality of the picture.

What is your gut feel ? Do you continue dialling in the timing curve, or do you wait for the premium ?

The coil has two circuits, a primary and a secondary.

The secondary circuit pumps out muchos volts via the HT leads.

The primary circuit receives much lower volts via the ignition wire, and can be safely measured at the + and - terminals on top of the coil.

 

That picture is worse than crap so I've attached the actual spreadsheet.

Next time you plot a curve, check the timing at 1,000 rpms as well. I simply used an estimate.