How to do the ignition timing on a mangusta

Ben,

You should be fine with an initial advance of 8-10 degrees. Figure a total advance for a SBF at around 34-36 degrees as a good starting point.

Steve

Yes, start with 34-36 total advance with the vacuum plugged. Then reattach vacuum. If you car idles fine, use ported vacuum. If you need more advance at idle, use permanent vacuum source.

That's the ideal world, here comes the limitations in the real world:
-If the starter can't handle it, get a better starter or reduce idle advance, this is most easily done with an adjustable vacuum advance
-If it pings at WOT, reduce Total advance
-If it pings at 2-3500 rpm, medium throttle, either reduce vacuum advance, or change springs etc in distributor to harder, so the mechanical advance comes in later
(This is of course based on the assumption that you can hear a ping, with the engine behind you and a loud exhaust, this can be hard)
If all else fails:
http://www.tuningmadeeasy.com/...-an-ignition-part-1/
http://www.tuningmadeeasy.com/...-an-ignition-part-2/

Mikael,

Nope. You want 34-36 TOTAL advance with the vacuum connected and engine RPM's at 2500 or so. Total is a sum of initial, mechanical, and vacuum advance numbers.

Some advance units will give you much more than this. Distributors from the smog era will give you much more mechanical advance. With totals up into the 40's+!

I run my distributor with no vacuum connected. I run 8-10 degrees of initial advance and 26 degrees of mechanical advance. (Number on the cam tower advance mechanism X2.) All the advance is active by about 2000rpms.

The reason that the manufacturers did this, allow such high advance numbers, is so that when in times of high vacuum (off the gas pedal, going down hill...) the ignition would advance to allow better burn of the mixture....or some propaganda like that.... In a performance car, it can lead to more premature ignition or pinging at inopportune times.

If you want the car to behave properly, and still run the vacuum advance, you will definitely want to use the ported vacuum connection on your carb. Otherwise, a full vacuum will screw with your idle levels all the time......

Steve

quote:

Nope.

Well, I beg to differ.

In general: Most distributors would not have full mechanical advance present at 2500, so if you adjust by that rpm to 34-36 degrees, you'll get too much advance at higher rpm. With your curve it should be OK. But adjusting with a vacuum line attached should not be done either, partly because any small degree of change in throttle angle will seriously affect the number. Here's a quote from the MSD instructions:
"Total Timing: This is the total of the initial timing plus the centrifugal advance added together. Example: 10° Initial + 25° centrifugal = 35° Total Timing. (When checking Total timing, disconnect and plug the vacuum advance.)"

Another general comment: There's no need to not have a vacuum advance for a street car. OK, it removes complexity, but a correctly tuned vacuum advance provides:
1. better idle
2. better part throttle response
3. better fuel economy

Ben, sorry to give you conflicting messages, but since you are running a vacuum advance, I suggest you do it as I've described

Good luck with it. (If you invite me to Hawaii, I'll be happy to help you...)

Well, I guess there is the opinion of my experts with the dyno, the opinion of the OEM folks, and then there is yours.

A correctly tuned and connected vacuum advance should not even affect idle on a Ford as it should be connected to the delayed vacuum port on the carb. ("ported vacuum")

As for part throttle response, it could go either way....depends on your curve. Too much vacuum advance and you are pinging....

Fuel economy, perhaps, but I was always under the impression that the vacuum advance was used for cleaner emissions, although fuel economy could benefit slightly at steady state cruise speeds. (Not likely where Ben lives! )

With my old engine and the new one, I had/have a rock smooth idle, the best throttle response I've ever had in a car, and unfortunately, not enuf miles to figure out fuel economy yet....


As with all things Mangusta, your mileage may vary....!

If you are running the stock Ford distributor, follow what Ford recommends... If you are running an MSD distributor, I refuse to help you as MSD in my book stands for 'My Stupid Distributor'..... No need for flames...it's my opinion. I'm just saying that I rarely if ever hear the expression "my points or DuraSpark ignition system isn't working right".....yet I go to a Pantera club tech session and almost always hear of someone with MSD problems of one sort or another. I've been running DuraSpark II in all of my cars for over 25 years and have only had one pickup module go bad....they work, and parts are easy to come by. Difficult to argue with that sort of track record....not to mention a bazillion station wagons and trucks....


Steve

quote:

Well, I guess there is the opinion of my experts with the dyno, the opinion of the OEM folks, and then there is yours.

Are you for real?!

This is not about who's right, it's about helping Ben. I'll let you have the last word in this pissing contest, but before I do, I'd better comment on a few things, because people may read this post for help...

quote:

on a Ford as it should be connected to the delayed vacuum port on the carb. ("ported vacuum")

Normally it's connected to a ported vacuum source, agree. Whether it's a Ford V8 or another brand is irrelevant. But some engines with perhaps wilder cam and other stuff may experience so low quality idle, that changing the vacuum advance from ported to direct will help idle.

quote:

fuel economy could benefit slightly at steady state cruise speeds

Fuel economy tends to improve all over, except at WOT where vacuum is close to zero.

quote:

If you are running the stock Ford distributor, follow what Ford recommends

If it sits on a stock Ford engine, then yes. If that stock Ford distributor sits on an engine with wilder cam, intake, headers etc., then it needs another curve, regardless of it being a Ford or an aftermarket distributor. Normally a curve where the mechanical advance comes in faster.

quote:

MSD

I'm not for or against MSD. I've had it before without any problems, but I read many places that they've let their quality drop. Today I drive cars with OEM, ACCEL and ICE ignition. The only reason I mentioned MSD was that I had their instructions close by, and I thought that seeing in black and white, that a major vendor like them clearly states that vacuum advance should be disconnected and plugged when setting Total Advance, would be seen as a valid argument. Apparently not...

Ben, you're welcome to contact me directly if you want.

Over and out.

Thanks everyone for your input.

One thing to add. If you have a car with the smog pump removed, as well as the tubes, etc; then do not forget to change the vacuum advance mechanism on the distributor to a pre-emissions part, like 1964 or before.
I do not know about Fords but the B-1 is the pre-emission vacuum advance used on all GM high performance engines.

I did not know what that part attached to my distributor did so I found out on the internet when trouble-shooting my engine idle problems. I changed it to a B-1 and it felt like I took 1000 pounds off of my car in first gear coming off of idle.
The early, 1967-70 engines had vacuum advance mechanisms that RETARDED the spark at idle, pouring gas into the exhaust manifold so that the fire could be lit to eliminate the unburned hydro-carbons. Your government at work! This also led to idle overheating and low fuel economy. This is the opposite of what it used to be, 12-14 degrees at idle speed.

To properly set timing you have to consider all effective factors, car weight, engine size, tuning, etc,; tire size and final gear ratio.

Just run the highest advance you can for the best fuel economy, the performance will follow.

Dick Ruzzin

The US Mangusta, as far as I know, used the 68 302-4v Ford.
It is a very "mild" engine. Camshaft timing is the same as the 302-2v.
It has higher compression then the 2v, advertised as 10.5:1.
The distributor I have for mine, is the manual transmission part (according to Ford listings) and has a single port vacuum diaphram.
As far as I know, the vacuum diaphram is calibrated to use intake manifold vacuum, rather the carb port vacuum.
Stock advance setting at idle is 10 degrees.
Mechanical advance on it is slow. It is supposed to be fully in by 5000 engine rpm but never quite seems to get there.
At 10 degrees initial, you will see probably about 34 degrees total advance.
34 to 36 is about all the engine will respond to AND that was for 103 octane pump gas.
The 289-302 engines seem to be able to run decently on even regular grade pump gas.
They can be difficult to detect pinging and on a Mustang, you usually need to pull the shift boot off so you can hear the sound of the exhaust.

If you are sure everything is stock in your engine, set it to 10-12 degrees at hot idle and leave it.

What you get out of it is all it is capable of delivering and really is pretty much out of breath by 5500rpm.

Now if you have modified the engine even with just a camshaft change, then you need to experiment with the distributor settings.

Likely it will like 12-14 like the 289hp engine does and you will benefit by changing advance springs for a faster curve.

Advance all in by 3500engine rpm is likely the quickest you will be able to run on high test pump gas, but with a modified engine, all bets are off and you are on your own to find the best combination.

In "the old days" with Sunoco 260 (103 octane) right in the pump, you could be all in by 2,500 engine rpm BUT speaking from experience, the springs that were used for that were so light that they would stretch out quickly, i.e., fail.

I have had success with using 14 degrees initial timing, and 36 total on high test pump gas in my 347 (which is a 68 3024v) and setting the rate of advance to be all in around 3500-3800.

Try the stock 289HP distributor springs for this. There is one heavy spring, and one medium spring.

In any situation, the 302 is an easy engine distributor to time to your situation.

Like I said, if it is all stock, use stock timing settings. You cannot go wrong with that.
If it pings, all is not lost, it is probably the rate of advance is too fast for your gas and you may be able to just back off 2 degrees or so initial and be finished with it.

Just MY experiences with this engine over the last 40 YEARS. Not trying to throw mud at anyone else or say I am smarter then anyone else.

Hope this helps. That is the interntion.

A couple of additions: MSD uses Ford-sourced parts inside their billet distributor bodies. Normally, those parts do not cause problems; it's the MSD brain-boxes that go south regularly.
Next, a Duraspark 2 vacuum advance adjusts: a 1/8" allen wrench inserted into the vaccuum hose bib engages a small needle valve inside. If you have 'wrong' amounts of vacuum advance from your engine, advance, no aftermarket parts are necessary to adjust a Duraspark. MSDs do not normally adjust vacuum but there are 'kits' available.
Third, do not get too hung up on the amount of any given timing numbers. Remember, your engine does not CARE what number appears on the harmonic balancer or a dial-back timing light. All it 'wants' is a spark at a near-optimum time and a host of things can change this. So if you set the distributor to "optimum" and the engine pings, feel free to back off any or all the tuneable parameters until no ping is heard nor felt. A dyno run is the ideal way to set timing but unless you get a deal, this will run over $100.
Your POCA Newsletter has a horror story (with a happy ending) on expensive aftermarket parts installed out of the box, resulting in poorer running than before. A dyno check saved the day.

I've had a really good experience using a Petronix kit installed in the original distributor and their matching coil.
I was turning the engine over with a remote starter and the coil wire pulled.
It must have thrown a lightening bolt four or five inches to ground. Just missed me.

The MSD brain is something to avoid. One year I went through three thinking it was me. It wasn't they are crap. Avoid them at all costs.
Some people think that they have let the quality of the "brain" go to hell? This is presumptuousness. It never had any to begin with.

The Ford vacuum canister you speak of has the hex nut configuration near the vacuum nipple. I don't remember what the adjustment range is on them but it is a lot. Good suggestion BW.

http://www.tuningmadeeasy.com/...-an-ignition-part-1/

http://www.tuningmadeeasy.com/...-an-ignition-part-2/


Might help?

There are many debates about whether ported or full manifold is the best and it might depend on your engine, ie cam or vacuum it pulls at idle. Best to test and see what works best for you.
Generally full manifold for lower engine temp, better idle, ported for faster warm up, higher idle temp.

A couple of interesting links..
Link1
Link2
Link3

Neither the Ford 427, or the Ford 289hp engines, 63-67, use vacuum advance distributors. They are strictly mechanical advance distributors.

They were dual point distributors which was done to increase the available dwell.

They were designed for real high performance, which in those days meant racing. They were perfectly at home street driving or racing. They are very versatile devices. Generally well built with few problems.

The vacuum advance distributor CAN give you 2 more MPG,which is what it was initially intended to do, but the drawback is that at high RPM, they tend to be erratic and cause inconsistent timing starting around 6,000 engine rpm, sometimes lower.

Because of the initial struggle to deal with exhaust emmissions inexpensively as possible, the auto manufacturers found the vacuum modification of the advance/retard of timing in the distributor helpful.

If you are going to run an engine hard for maximum performance (over 6,000rpm) you really do not want a vacuum advance distributor at all.

The debate over ported or engine vacuum becomes a technicality along with the "how many Angels can sit on top of a pin" discussion?

quote:

If you are going to run an engine hard for maximum performance (over 6,000rpm) you really do not want a vacuum advance distributor at all.

Why not? Vacuum is close to 0 at that rpm, so the advance doesn't come into play. Vacuum advance aids economy, emissions and idle quality, and if done correctly, doesn't hurt any performance.

The Ford vacuum distributors are erratic around 6,000 rpm and over.