Rick, I run my 358ci yates(cleveland) headed motor at 30 degrees initial and 30 degrees total. Its all in all the time. If it will start and does not ping, more timing is a good thing. On the total, I agree with Scottj's comments, it depends on how efficient your heads and motor are at peak power. With yates heads, 30 total is max power, with a typical FE head, they are less efficient and need more total for peak power. Good luck, Scott.

Seem to me I have 24 in the dist. A good builder, who lurks around here as well, told me that my engine will like 42-46 total. With that in mind, I can bump my initial (I always set by total) to 18 - 22. I am going to sneek up on it and see what happens. I to have no vacuum advance and until all the timing is in, the motor could be a little more 'crisp'.
Thanks
Rick

Watch for that ping monster. With those pipes you may not hear it.

To be honest I asked the guy who built the engine of the winning car at the 500 to come and look. He said 38 would be all he would set for a total, given the CAM and engine.

Rick, be mindful of too much.

Thank you Scott for that insightful explanation..
Coupled with what I thought I already understood regarding this issue, I feel MUCH more enlightened now....
My "local" guy suggested that I run a max. advance of about 36 degrees with the intial reading to fall somewhere around the 16 degree mark. I plan on recurving my MSD this winter to do this and fit a new Mighty Demon 850 to the manifold at the same time.
Just losing the air horn should take care of a lot of my airflow issues that I believe I am currently suffering from. Let alone, I am ditching a pretty poor carb that was selected by the previous owner...
I just have to make sure of my hood clearances and I will probably go the Demon route too...
Thanks again guys....
Pat

Did anyone ever set the initial advance by the vacuum gage ?
How much did the gage dictate.
How high was the idle rpm?

Michael,

Yes you can set it with a gauge. Set it to the highest vacuum reading shown on the gauge. When it starts to drop off you are to high.
It does not always work very well with modified engines.

I have never heard of using a vacuum gauge to set timing..There are too many variables, like carb adjustment, rpm, etc. to set timing this way. The method of highest vacuum can be used to set idle mixture, but you'll also find this method will put you on the lean side. Not saying this method doesn't exist, but why not just use a timing light?

The vacuum gage setting the timing came up twenty years ago.My nephew bought an older GTO .The oem dampener had slipped, its timing marks were off a little. I myself haven't ever used it to date .The not working on a modified engine , I hadn't heard, and the lean side ,I can see how it would do that.so untill the gage quits climbing then backthe timing off a touch ?

As Jack mentioned, I have used a vacuum gauge to set idle mixtures for years... It can leave you lean if you don't look at what you are doing.. Basically, I look for the point where the high vacuum mark starts to be realized (while moving the screw from rich to lean) and I leave the setting on the rich side of the "high vacuum zone" on the screw...
There is also one other, highly "unscientific" method called the "Dick" tune method (after my good friend Dick Wilson) for setting idle mixture screws on Holley carbs. Taking a close look at either a tach or a vacuum gauge, slowly turn the mixture screw in (lean) until the engine rpm or vacuum JUST begins to fall off. Look at your mixture screw and back it out exactly 1/2 turn.. THAT's IT! This method can be done "on the road" without a chest full of tools and guages and ironically, it usually works out to be VERY close to the proper mixture setting for a Holley.... So, just "DICK" tune it.. as we used to say...:D

I see lots of you have read my Demon Tuning 101 article, have you read the Mission Ignition article?

http://www.4secondsflat.com/Mission%2520Ignition.html

Study the chart at the bottom od the page, it may help you understand your performance engine and how the changes you make affect the timing issues.

One more note...42-46-48 total timing????I've never heard of such numbers on a Unleaded low octane motor??

Unless the combination is so poor that it needs that much lead to make it run...I just don't believe that that motor makes max HP at those numbers.

We used to set our SB Chebby Alcohol injected 8000 RPM Sprint Car motors at 42* on a Mag, but on a street car I'd have to see that to believe it.

Send me a spark plug I want to look at it.

I don't claim to be an Ford engine master and I'm the first to admit it, give me a boring machinme and you might as well of given me a file.

But with my 35 Years of experience in tuning ignition and carburetion I wish engine builders would admit that they aren't tuners, and consult with someone that is before they build these wild combinations...you just wouldn't believe what I run into, some stuff I just refuse to work on it's so far from reality that no carb and no amount of ignition tuning will ever make it run in the application intended.

I work with several builders and cam grinders and we always discuss my end with there idea's before the grinder gets put to the steel....final result is a perfect combination well within the capability's of the owner.

Cuda66273
 

Thanks for your feedback and I will send you a plug or two! I have enjoyed your tech articles more than once and when the day comes to go Demon, you are on the top of the list.

I have run total timing from 36 to 44 degrees and never noticed much of a difference. Just seat of the pants. I have never actually taken performance measurements. But it seems to run fine just about no matter where I set it.

I recently put in a slightly hotter cam (226 and 230 versus 214 and 226) and have not tuned the carb. At last glance with the new cam and new plugs, they look a bit lean to me and as though they did not have enough timing (if I am reading your site correctly) with 38 degrees total.

I will yank one as is and send it to you Monday.

Thanks
Rick

Personnaly, I do not know if I have ever read anything from cuda66273, but I agree on the timing numbers.

We ran blown Alcohol with a total of 40. More is an invitation to damage parts.

Hey, just my opinion.

With that much timing the plug will read lean, the fuel is all gone before it reaches TDC.

Let me see that plug and we'll make a determination.

Cool! I will ship them out. Hard to tell how long it will take to get there!

Thanks very much

Rick

Is that you Don?
Good to see you here...
I have put together all of the specs I could rergarding my Cobra on your "spec sheet" and I will be emailing it to you soon...
I look forward to strapping on the Demon (Mighty 850cfm) this winter...
I plan on re-curving my distributor just before I do the carb.
I have a 460 Ford Crate motor. A local told me to go up to 36 degrees total advance at about 3000-3500RPM(?) with initial timing somewhere around 15-16 degrees. My cam specs are 244 intake/254 exhaust at .050". I am running about 10.5:1 compression according to the specs that came with the car...
I know this is very limited info, but does that advance curve sound about right? Is this too early to be at full advance?
Pat

cuda66273
 

Well, I pulled a couple of plugs and have them setting on my desk to ship to you. When you get them, if you could post here when you get a chance to look at them that would be great, then perhaps I can share what comes out of it and we can all benefit.

I don't have a picture to post and my eyesite is not what it used to be but here is a general description of what they look like.

- Both look to be very similar.

-Threads appear to be discolored about 1.5 to 2 threads down. Dry for the most part with some signs of the antiseeze I always put on them.

- Ground strap is a tannish grey. The color is very even across the horizontal part above the electode. The moment the ground strap begins to turn down toward the body, the strap slowly gets darker until it becomes a dull black about 1/16" above the body, even with the top of the porcelain.

- The top of the threaded body has a very light, but even dull black color. Actually, the same color and amount of coating appears to extend all the way to the bottom of the threaded body on the inside of the plug.

- The electrode is the same color as the ground strap above it, except the very end of the electrode, on the flat only, is also a dull black color.

- The top of the porcelain is off-white. The moment the porcelain begins to drop down into the body, there is a tan ring. The ring does not go all the way around the top but rather stops shy of the ground strap on one side and come all the way to the ground strap on the other. The depth of the ring varies from 1/16 to 3/32". Immediately below that top ring is a very narrow off white ring, same color at the tip of the porcelain. About .020 to .030 in width. Below that, and as far as I can see with the naked eye, the plug is once again the same tan color as the top ring and continues all the way down.

It looks most like plug 19 or 23 from your chart. I will be interested in what you have to say!.

Thanks
Rick

PJS50:

It's me alright....

Your friend is close but a bit diffeent than what we would set it at:

I think you should probably have about 20 Initial and all in at about 3100 to a total of 34-35 with unleaded fuel on that compression ratio with a 244 cam.

I'd need all the specs to be sure.

Also dialing in a 460
 

PJS50, I have also been talking to Don with my timing and Carb. tuning. I have a slightly aggressive Crane roller cam with about your lift. Trying to tune in with a Speed Demon - until I get mad and order a Mighty Demon from Don. Sneaking up on timing - at 12 and 32 and going to 15 and 35. My idle circuit had to be enrichened to start well, but runs "fat" at idle. More timing should help, but need to hold at 15/35 until I can recurve the Ford Dist. or switch to MDS and machine the proper stop for 35 total. PJS50, I'm right up the road from you in Clarkston - give me an e-mail if you want another pair of hands or set of eyes (no opinions) - daddy1dave@aol.com

Great Thread ("Dick tuning" - who would have thought)