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Author Topic:   distributor/timing help needed
craigber
Journeyman

Posts: 54
From: Vancouver, Canada
Registered: Sep 2000

posted 01-19-2001 11:53 AM     Click Here to See the Profile for craigber   Click Here to Email craigber     Edit/Delete Message   Reply w/Quote
Hi everyone,

frustration is definitley setting in...mild 351C rebuild...performer intake, 1406 carb, blaster coil, MSD wires, etc. am using an Accel 34202V distributor (dual point with vacuum advance) converted to Pertronix (timing chain at 0)...have tried everything humanly possible to get the timing right but no luck...distributor came with very light springs and 24 degrees total...got pinging...changed to 20 degrees total...got pinging....changed springs, many combinations using an MSD advance curve kit...heavier springs help but she runs "fat" (good term for sluggish)...with light springs she goes great and I can get by with a soft touch but soon as I get her into the throttle....pinging...no matter what fuel I use or advance curve I try I just can't seem to get rid of the pinging...also can't seem to get my intial timing above about 8 degrees advanced (no matter what curve I use) and if I get rid of most of the pinging with the heavier springs I can't seem to get my vacuum advance set up to work right (basically it is disabled right now)...I have read many posts as well as books/web stuff on advance curves...Ford rebuild book says to hook up vacuum advance to manifold vacuum rather than venturi ported...tried this but didn't really run great...don't know the mods to make this work...any and all help greatly appreciated....

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Craigber
71 Red Rag

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sigtauenus
Gearhead

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From: Beaufort, SC
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posted 01-19-2001 03:53 PM     Click Here to See the Profile for sigtauenus   Click Here to Email sigtauenus     Edit/Delete Message   Reply w/Quote
This may sound dumb, but I thought that converting to Pertronix elimates the vacuum advance?

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SteveLaRiviere
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From: Saco, Maine USA
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posted 01-19-2001 04:21 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
That is very odd! Pinging at 24* total?

Are you sure the timing marks on the balancer are correct?

What do the spark plugs look like?

Pertronix doesn't eliminate advance, Sam, you are thinking of dwell.

------------------
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'97 Probe GTS 2.5L Disposable Commuter

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sigtauenus
Gearhead

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From: Beaufort, SC
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posted 01-19-2001 06:18 PM     Click Here to See the Profile for sigtauenus   Click Here to Email sigtauenus     Edit/Delete Message   Reply w/Quote
Oh

We'll have to talk about that some more then.

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craigber
Journeyman

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From: Vancouver, Canada
Registered: Sep 2000

posted 01-22-2001 11:41 AM     Click Here to See the Profile for craigber   Click Here to Email craigber     Edit/Delete Message   Reply w/Quote
Hi,

plugs look good....played with the advance curve and have it running pretty good now...the timing marks on my balancer are a bit off (TDC is actually about 4 degrees after TDC) and I have taken this into account...my question now is how is it that the stock Ford distributor was set at 10 degrees (20 crank) and factory timing (initial) set to 6 degrees....my math says this would give a total of 26 degrees (assuming the vacuum advance was locked out). According to everything I have read, I should be able to lock out my vacuum advance and set my intial as high as 16-18 degrees....not possible on my 351C...most I can advance it is about 8-9 degrees intial...comments (or am I completely out to lunch on this one???)

thanks

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Craigber
71 Red Rag

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Moneymaker
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From: Lyons, IL, USA
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posted 01-23-2001 05:55 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
Craig, try this please. Hook up your vaccum advance and rev the engine up to about 3500 RPM. Turn the distributor slowly CCW until the engine begins to buck. Then back it off about 1/4 of an inch and lock it down. Road test and see if it still pings.

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Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
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Scott (69Mach)
Gearhead

Posts: 289
From: Walnut Creek, CA USA
Registered: Jun 99

posted 01-23-2001 06:00 PM     Click Here to See the Profile for Scott (69Mach)   Click Here to Email Scott (69Mach)     Edit/Delete Message   Reply w/Quote
Meters, we don't need no stinking meters!

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mustangs68
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From: Hampton,Virginia,USA 1968 Fastback & 1995 Vert MCA#39406 M&M #12
Registered: May 99

posted 01-23-2001 09:37 PM     Click Here to See the Profile for mustangs68   Click Here to Email mustangs68     Edit/Delete Message   Reply w/Quote
You said it Scott!

Place a glass of water on the air filter cover and when the water ripples are gone she perfect!

sam

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craigber
Journeyman

Posts: 54
From: Vancouver, Canada
Registered: Sep 2000

posted 01-24-2001 12:38 PM     Click Here to See the Profile for craigber   Click Here to Email craigber     Edit/Delete Message   Reply w/Quote
hi Alex,

thanks for the tip...I will try it this weekend and let you know....CCW...so I will retard it till it bucks and then advance slightly...any suggestion on how much vacuum advance I should put into my timing? I have about 7 degrees crank due to vacuum right now...is that too high or too low...I am not greedy but I want snappy acceleration and decent fuel economy....

thanks again...

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Craigber
71 Red Rag

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FloJoe
Gearhead

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From: Port Orange, FL, USA
Registered: Dec 2000

posted 01-24-2001 01:30 PM     Click Here to See the Profile for FloJoe   Click Here to Email FloJoe     Edit/Delete Message   Reply w/Quote
"MOUTHWASH!? WE DONT NEED NO STINKIN' MOUTHWASH!"
-Arrr

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Joe Fields
68 Fastback 289ci bored .030 over
C-4

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Moneymaker
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From: Lyons, IL, USA
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posted 01-25-2001 12:44 AM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
I would like to see what you have total when it stops pinging before I make anymore suggestions.

------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
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craigber
Journeyman

Posts: 54
From: Vancouver, Canada
Registered: Sep 2000

posted 01-25-2001 01:34 PM     Click Here to See the Profile for craigber   Click Here to Email craigber     Edit/Delete Message   Reply w/Quote
Hi Alex,

I think I have my problem solved...have 20 total in the distributor...initial set to about 8 and my vacuum is putting in about 9...I calculate this to total about 37 degrees...i have a relatively fast curve which maybe is why I can't lock out my vacuum and set my initial any higher...seems to be running fine now...idle is fine...appears to be no pinging upon hard acceleration...hope this makes sense and thanks for all the help (everyone)

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Craigber
71 Red Rag

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Gary DelVecchio
Gearhead

Posts: 167
From: Plano, TX, USA
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posted 01-25-2001 01:45 PM     Click Here to See the Profile for Gary DelVecchio   Click Here to Email Gary DelVecchio     Edit/Delete Message   Reply w/Quote
So what fixed it??????????

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Moneymaker
Moderator

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From: Lyons, IL, USA
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posted 01-25-2001 02:57 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
Another happy Mustangsandmore.com member! I love it!

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Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
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craigber
Journeyman

Posts: 54
From: Vancouver, Canada
Registered: Sep 2000

posted 01-25-2001 04:29 PM     Click Here to See the Profile for craigber   Click Here to Email craigber     Edit/Delete Message   Reply w/Quote
can't honestly pin down what fixed it...seems to me that you can't change one component of timing without considering all of the others...appears that I finally found (by trial and error) the proper combination for my engine...I think the timing curve was crucial to getting rid of pinging....I have a very light spring (from Accel) with a moderate spring (from MSD kit) and this combo seems to work...anyways now I need to find a speedo cable (obsolete from Ford in Canada)....sigh...always something!!!

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Craigber
71 Red Rag

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PJHMustang
Journeyman

Posts: 35
From: Granada Hills, Ca., USA
Registered: Jan 2001

posted 01-28-2001 12:41 AM     Click Here to See the Profile for PJHMustang   Click Here to Email PJHMustang     Edit/Delete Message   Reply w/Quote
Craig, the vacuum advance should not be considered in your total advance, just the initial and distributor X 2.
The vacuum advance is all about driveability and economy, not performance.
If you have 20 degrees in the distributor you should have 16 to 18 initial.
I would like to suggest a Crane Cams adjustable vacuum advance. Crane also markets an advance kit for the centrifugal advance set-up. This kit comes with instructions which in themselves are worth the price. See Summit.

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Moneymaker
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From: Lyons, IL, USA
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posted 01-28-2001 11:07 AM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
WRONG PHJ! The vacuum advance definatly ADDS to the total advance. The sole purpose of it is to limit and regulate the amount and when it's applied.

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Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link

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PJHMustang
Journeyman

Posts: 35
From: Granada Hills, Ca., USA
Registered: Jan 2001

posted 01-29-2001 08:57 AM     Click Here to See the Profile for PJHMustang   Click Here to Email PJHMustang     Edit/Delete Message   Reply w/Quote
Moneymaker, we need another voice of wisdom here to break this tie. I'm sure I can't change your mind regarding the vacuum advance being part of the total advance just like I know you could never change mine.
Anybody out there care to chime in?
Pat.

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steve'66
Gearhead

Posts: 3509
From: Sonoma,CA,USA
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posted 01-29-2001 10:36 AM     Click Here to See the Profile for steve'66   Click Here to Email steve'66     Edit/Delete Message   Reply w/Quote
Pat,

Sure I'll jump in.

Vac. advance is in addition to mechanical advance.

They are two seperate mechanisms, one being affected by a ported vacuum signal and the other affected by rpm. Neither advance system can retard the spark (other than removing advance that they added), they only add varying amounts of advance. Since they work independantly of each other, the vacumm advance has to add to the total.

SteveW

[This message has been edited by steve'66 (edited 01-29-2001).]

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craigber
Journeyman

Posts: 54
From: Vancouver, Canada
Registered: Sep 2000

posted 01-29-2001 12:00 PM     Click Here to See the Profile for craigber   Click Here to Email craigber     Edit/Delete Message   Reply w/Quote
I am glad that someone is addressing this issue...different sources give different opinions...some say it adds to total, others say not...I think it does add to total as I get different advance readings when it is hooked up...regardless, the car is running pretty good right now so I thiink I will leave it for a while and concentrate on other things like speedometer needle bounce....lubed cable, drove speedo head with a variable speed drill, seems OK, probably need to look at nylon gear at tranny...thanks for all the help..

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Craigber
71 Red Rag

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craigber
Journeyman

Posts: 54
From: Vancouver, Canada
Registered: Sep 2000

posted 01-29-2001 12:57 PM     Click Here to See the Profile for craigber   Click Here to Email craigber     Edit/Delete Message   Reply w/Quote
hi guys,

thinking again about vacuum advance...I don't think that vacuum advance can in fact ADD to total timing...it can bring in advance under certain engine conditions but because of the mechanical stops in the distributor, it could never add more than what is there...I think it definitely changes the advance curve but doesn't affect total...

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Craigber
71 Red Rag

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Scott (69Mach)
Gearhead

Posts: 289
From: Walnut Creek, CA USA
Registered: Jun 99

posted 01-29-2001 01:16 PM     Click Here to See the Profile for Scott (69Mach)   Click Here to Email Scott (69Mach)     Edit/Delete Message   Reply w/Quote
I'm with Craigber on this one. I think the vacuum advance affects the rate, but not the total advance amount.

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n2oMike
Gearhead

Posts: 654
From: Spencer, WV
Registered: Jan 2001

posted 01-29-2001 01:26 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
Vacuum advance DOES add to the total timing, it just does it at part throttle. At full throttle, the vacuum advance goes away, and all you've got is initial and mechanical.

Under light load (high vacuum) the fuel charge density is very low, and extra timing can help the burn. Vacuum advance was developed to give the engine extra timing under these conditions.

Problem is... if the vacuum advance isn't adjusted correctly, it might not go away quickly enough, and the engine will see too much total timing.

As for the 351C, I'd try jetting up that Edelbrock carb a tad or swapping metering rods. Edelbrock tuning kits are available for these engines. Some Edelbrock carbs come calibrated a bit lean... especially the ones that are sold with electric chokes.

Good Luck!

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Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/motorcitymustang/cmml/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367

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steve'66
Gearhead

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From: Sonoma,CA,USA
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posted 01-29-2001 01:31 PM     Click Here to See the Profile for steve'66   Click Here to Email steve'66     Edit/Delete Message   Reply w/Quote
[QUOTE]Originally posted by craigber:
[B]hi guys,

thinking again about vacuum advance...I don't think that vacuum advance can in fact ADD to total timing...it can bring in advance under certain engine conditions but because of the mechanical stops in the distributor, it could never add more than what is there...


Craigber,

There are two different "mechanical stops". The mechanical advance moves the cam on the distributor shaft, and the vacuum advance moves the point mounting plate in relation to the cam. They are really seperate advance mechanisms and they are not limited by a common stop. Get an old distributor and check it out, I'm still with Alex on this one. Anyone else?

SteveW

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SteveLaRiviere
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From: Saco, Maine USA
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posted 01-29-2001 03:47 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
Of course vacuum advance is added to initial and centrifugal to get a total timing advance.

It's not a matter of voting, that's a fact.

------------------
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'97 Probe GTS 2.5L Disposable Commuter

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Bob Hopkins
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From: BRIDGEPORT NJ USA
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posted 01-29-2001 03:49 PM     Click Here to See the Profile for Bob Hopkins   Click Here to Email Bob Hopkins     Edit/Delete Message   Reply w/Quote
Being a new member will jump in the s#*@! I think you are talking two ways ported vacumn will add to total advance , manafold vaculm will not add to total EXCEPT under high vacumn conditions ie: idle,decelerating, and light load cruse. Beeing a old fart i like manafold vacumn ,to help idle quailty,and help add some fuel milage under light cruse, never have felt vacumn advance would be as accurate and reptable to consider as part of total advance.

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PJHMustang
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From: Granada Hills, Ca., USA
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posted 01-29-2001 04:57 PM     Click Here to See the Profile for PJHMustang   Click Here to Email PJHMustang     Edit/Delete Message   Reply w/Quote
Normally the suggested "total timing" required for small block Fords is 36-38 degrees, sometimes more. Now if the vacuum advance is included in this "total advance" I can tell you how to find a bunch of power.
It is obvious to anyone who understands how a distributor works that the vacuum advance does add to the overall timing, I don't argue that for one second but the meaning that is being applied to "total timing" is the heart of the problem.
The vacuum advance is opperative only during part throttle conditions. The necessity for the vacuum advance is because at part throttle or high vacuum conditions the cylinders don't get filled with air/fuel mix so the molecules are further apart and require more time to build the fire before the power stroke is too far down. The amount of vacuum advance required varies with a number of things such as load, elevation, humidity, mixture density, etc.
When power is required the vacuum advance is suddenly inoperative and not a part of the equation. "Total advance" the way I have always read is just initial and centrifugal combined, and the vacuum advance being treated as a separate system, hence the suggestion of the adjustable vacuum advance from Crane Cams.
Rather than stating flat out "you are wrong" it would be easier to accept if one was to say I dissagree. I don't think we are that far apart to tell you the truth.
Pat

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steve'66
Gearhead

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From: Sonoma,CA,USA
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posted 01-29-2001 04:58 PM     Click Here to See the Profile for steve'66   Click Here to Email steve'66     Edit/Delete Message   Reply w/Quote
Bob,

In the interest of clearing this up, why would you connect vac. adv. to manifold vacuum? I don't understand that, because your max vac. signal would be at idle, and your maximum vacuum advance would be in at idle and lower as the throttle opens.

I always thought vacuum advance is connected to ported vacuum (a vacuum port on the carburetor above the throttle plate). Ported vacuum works opposite of manifold vacuum. ie. no vac at idle and max vacuum at w.o.t.

Am I confused about this? Shouldn't vac advance be connected to ported vacuum?

SteveW

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SteveLaRiviere
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From: Saco, Maine USA
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posted 01-29-2001 06:32 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
After thinking about it, Pat, I see what you mean.

When you set timing, you disconnect the vacuum advance and set the initial timing. The advance curve is dialed in through weights and springs and checked at 3000 or so to verify that the 'total timing' occurs by the rpm you dialed it in for.

Then you hook the vacuum back up. The vacuum is a load sensing device, advancing the timing at high vacuum conditions, decelleration, going down hill, etc. It advances the timing beyound what the weights would for a certain rpm if it is needed.

So the statement that total timing doesn't include the vacuum advance is correct.

SteveW, the vacuum advance connect to ported vacuum, the retard, if equiped, to direct vacuum.

------------------
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'97 Probe GTS 2.5L Disposable Commuter

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PJHMustang
Journeyman

Posts: 35
From: Granada Hills, Ca., USA
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posted 01-29-2001 06:59 PM     Click Here to See the Profile for PJHMustang   Click Here to Email PJHMustang     Edit/Delete Message   Reply w/Quote
Lots of times a "dieseling" problem can be totally eliminated by connecting the vacuum advance to a ported source rather than manifold vacuum. A vacuum advance connected to manifold vacuum with a decent camshaft will drive a man to drink.
Pat

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SteveLaRiviere
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From: Saco, Maine USA
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posted 01-29-2001 07:44 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
I haven't run a vacuum advance in my Mustang since 1980!

------------------
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'97 Probe GTS 2.5L Disposable Commuter

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steve'66
Gearhead

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From: Sonoma,CA,USA
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posted 01-29-2001 09:49 PM     Click Here to See the Profile for steve'66   Click Here to Email steve'66     Edit/Delete Message   Reply w/Quote
Yeah,

We just run mechanical too Steve. If it was a strip only car I wouldn't even run the mechanical advance, I'd leave it at 38 degrees and retard the spark for starting with with the ignition box.

This was a good excercise. An educational discussion, with some good input by our newer members and old alike.

SteveW

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Moneymaker
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posted 01-30-2001 12:20 AM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
The point is that if you take a timing reading at the balancer with the vaccum advance disconnected it will read less timing than with it connected. No matter what RPM! So to set TOTAL timing with a vaccum assisted distributor you must set it with the vaccum advance hooked up. If you just want to set the initial or base timing like we have all been doing for years, then it's irrelevant.

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Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link

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Moneymaker
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posted 01-30-2001 12:21 AM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
PS I love a good argument Keeps the juices flowing.

------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link

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