need to advance timing- canister hits water neck

Blown4.6 · Jun 3, 2005

Max Power said:
Full vacuum poprt defeats the purpose of even using vacuum at all. You can just do the same thing mechanical.

Vacuum advance is meant to fine tune spark advance for optimum settings under certain load and throttle conditions. Running full manifold defeats that function.

In this case it works OK, becuase the owner can't be bothered to out the distributor in the roght location, but overall, that's not the most efficient use of spark advance.

Ummm, you are a little off with that statement. I jumped the wires to accomplish the EXACT same thing as resetting the distributor on the gear. Could the spark be more efficiently used? Of course. However, re-stabbing the distributor would have ZERO to do with it. I need to take the time to have someone put a full MSD ignition system in. For now, everything seems to work very well. How can you argue with that?

I timed it using ported vacuum advance. Still, if the initial was adequate for starting and idling, it would ping. If it wouldn't ping, it wouldn't start and idle and would get hot (not enough advance). That is why I went this way (full vacuum). The only thing I was "too lazy" to do was to have the distriubtor re-curved with 14 degrees advance initial and less total advance. This can be done either vacuum or mechanically.

With this (full vacuum) setup, I get max advance when I basically turn the key. The advance drops out as I get into the throttle to the point where it hits initial timing at WOT.

yeloxr7 · Jun 3, 2005

Blown4.6 said:
Awesome! I knew there had to be some "bubba" way to handle this!

I can't wait to see the "bubba" ways of handling problems on a Jag XK8......

Blown4.6 · Jun 3, 2005

yeloxr7 said:
I can't wait to see the "bubba" ways of handling problems on a Jag XK8......

Dude, that's probably just a little joke; but for the record, I monkey with cars like my bronco and my 'stang. My jag has a $12,000 aluminium engine;and no, I don't even change my own oil. I've got a couple better things to do (apparently respond to posts on this thing).

Blown4.6 · Jun 3, 2005

I'm pretty damn sure now that everybody who is recommending connecting the vacuum advance to PORTED VACUUM sorce, for non-emission controlled vehicles, are totally incorrect.

http://www.jalopyjournal.com/forum/archive/index.php/t-7609.html

Check out this thread and read the entire THIRD response (one that says "got time?"). This guy makes a ton of sense and apparently knows exactly about what he's talking. I have trouble arguing with the success that I just had and this guy. Sorry, FULL-TIME VACUUM is the way to go for a standard distributor with vacuum advance.

That should pretty well end this discussin (but I know it won't). I think this will be a little like dino vs. synthetic oil. Some guys, no matter how much proof you throw out, will still argue "their" point.

krash kendall · Jun 3, 2005

I will refer to this quote to point out the correlation between high engine temperatures, emission controls and ported vacuum source:

"Believe it or not the purpose of ported vacuum is to raise the temperature at idle, to lower NOx emissions."

The entire article can be found (for the naysayers review and or critique) here.

Blown 4.6, glad your car runs better!

Blown4.6 · Jun 3, 2005

krash kendall said:
I will refer to this quote to point out the correlation between high engine temperatures, emission controls and ported vacuum source:

"Believe it or not the purpose of ported vacuum is to raise the temperature at idle, to lower NOx emissions."

The entire article can be found (for the naysayers review and or critique) here.

Blown 4.6, glad your car runs better!

Good information and clarification on the point. At idle, you really want a lot of advance due to lean mixture. This seems to indicate that you want FULL vacuum (and it does). However, in order to raise combustion temps and to fully burn everything, a ported source is used to allow the fuel to continue to burn AFTER the end of the combustion stroke. With no piston to move, the energy from the still burning fuel (because of the later spark timing at idle caused by no vacuum when using ported source) can only go towards creating heat. This tends to reduce NOx.

That really clears things up. Good job!

If you're having trouble starting, idling and you're running hot at idle (and boy was I ever!), full-time vac is at leat part of the answer.

Max Power · Jun 3, 2005

Yep, that sure clears it up. A post on a bulletin board vs. factory Ford manuals and Ford engineers for 50 years...LOL!

I can set my car to 25 degrees advanced centrifugal and it still starts fine. Idle richness is the easiest thing to adjust on many cars so it doesn't have to be lean at idle. I could go on.

From the post, which was well thought out, by the way, the main benefit you get from running full vacuum instead of ported is easy starting. Fords have started easy for 40 years with ported vacuum to the advance.

Run what you want, whatever works for you. But if you are running manifold vacuum advance, you are not using the distributers advance curve as it was designed by the factory.

After considerable modifications, that may or may not be a good thing. Depends on your application.

84convertablegt · Jun 3, 2005

krash kendall said:
I will refer to this quote to point out the correlation between high engine temperatures, emission controls and ported vacuum source:

"Believe it or not the purpose of ported vacuum is to raise the temperature at idle, to lower NOx emissions."

The entire article can be found (for the naysayers review and or critique) here.

Blown 4.6, glad your car runs better!

that article schooled me. ive never really understood vacuum advance until now i guess. im gonna have to run out to the garage and redo my whole timing setup. damn!

Max Power · Jun 3, 2005

krash kendall said:
What gives? People who post here are constantly told to READ THE MANUAL. Now I'm actually getting ripped a new one for following the manual? The level of hypocrisy has reached a new high.

First of all, you're not being ripped a new one. Secondly, forgive me for not seeing a hypocrisy conspiracy of epic proportions.

Which manual are you referring too? It's not Ford, which is the one that is usually recommended here. I am guessing it is Edelbrock?

If so, how does Edelbrock know what you are running? Some carmakers recommend full, and some recommend timed port advance.

Just curious....

65ShelbyClone · Jun 4, 2005

Wait a minute...higher combustion temperatures create more oxides of nitrogen, not less. Thats what exhaust gas recirculation systems are for. This input obviously does not help with distributor tuning, though.

stangman16 · Jun 5, 2005

I had the problem where I would have to feather the gas every crank to get my '66 coupe to start. (would take several cranks & pumps of the pedal) but, I just switched the vacuum port to the full advance port, on my edelbrock 1406, and it starts right away. granted, I do have to keep charging the battery ev'ry time I want to start it, but I didn't have to constantly give it gas & numberous cranks. It runs much smoother, like never before.

Question: When I hook my vacuum gage up it reads about 14" of vacuum, is this normal? The vacuum gage I have indicates a "Normal Motor" green area between 17-22" of vacuum. I have a slightly mild unknown dur/lift cam on my 302 8.9:1 comp engine. With stock '78 heads (which sucks!), and 12° of timing.

D.Hearne · Jun 5, 2005

stangman16 said:
I had the problem where I would have to feather the gas every crank to get my '66 coupe to start. (would take several cranks & pumps of the pedal) but, I just switched the vacuum port to the full advance port, on my edelbrock 1406, and it starts right away. granted, I do have to keep charging the battery ev'ry time I want to start it, but I didn't have to constantly give it gas & numberous cranks. It runs much smoother, like never before.

Question: When I hook my vacuum gage up it reads about 14" of vacuum, is this normal? The vacuum gage I have indicates a "Normal Motor" green area between 17-22" of vacuum. I have a slightly mild unknown dur/lift cam on my 302 8.9:1 comp engine. With stock '78 heads (which sucks!), and 12° of timing.

If you had to hook the vacuum advance to full vacuum to get it to start, you had the timing retarded too much to start with.

Blown4.6 · Jun 6, 2005

D.Hearne said:
If you had to hook the vacuum advance to full vacuum to get it to start, you had the timing retarded too much to start with.

Not correct. Carbureted engines want about 25 degrees of advance spark timing to start and idle (particularly start). I certainly can be done with 8-12 (like if you run ported vacuum). I'm just telling you that the startup and idle mixture isn't ideal and wants extra timing . The ONLY reason for ported vacuum is to retard the timing at idle to increase combustion temps to reduce NOx. Further, ported vacuum advance is different from full-time vacuum ONLY in that it retards idle vacuum.

This is why many of you running ported need to "feather" the gas in order to make it start. What you're really doing is opening the throttle plates in order to show a little vacuum signal in order to try and advance the timing a little to start the thing. Ported vacuum is garbage. Use the scientifically correct advance curve by using a full-time vac source

D.Hearne · Jun 6, 2005

You do yours, your way, I'll do mine, my way. Unless it's cold out, I don't have to feather the gas to get it to idle when cranking it. And I've always used ported vacuum. When the engine is already warm, all it needs at most is to prime it with one punch of the gas pedal, then cranking it without using the pedal.

need to advance timing- canister hits water neck

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