mechanical or vacum advance?? - Vintage Mustang Forums
Vintage Mustang Forum
HomeForumGalleryClassifiedsAbout UsAdvertiseContact Us
» Auto Insurance
» Featured Product
Go Back   Vintage Mustang Forums > General Discussion > Vintage Mustang Forum
Vintage-Mustang.com is the premier Ford Mustang Forum on the internet. Registered Users do not see the above ads.
Reply
 
Thread Tools
Old 03-09-2010, 12:06 AM   #1 (permalink)
Senior Member
 
Join Date: Oct 2009
Location: chelsea, quebec
Posts: 324
Default mechanical or vacum advance??

Ive decided to go with a mallory unilight distrubuter to get rid of my old points system. But im having trouble deciding which route to take. I like the simple vacum advance plug and play but what benifits are there in going mechanical advance? How do you set up a mechanical advance? Im kind of lost when it comes to this.
Jays_68_302 is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 03-09-2010, 05:36 AM   #2 (permalink)
Senior Member
 
TommyK's Avatar
 
Join Date: Dec 2005
Location: CT
Posts: 1,005
Default

All distributors have mechanical advance but not all distributors run vacuum advance. If yours is a street car you should be running vacuum advance IMHO. When running vacuum advance the choice is whether to run full manifold vacuum or ported vacuum to operate the vacuum advance mechanism. I have set my distributor up to operate properly running full manifold vacuum for best performance but on a stock or nearly stock engine ported vacuum is best.

I am not an expert by any means but I would be happy to elaborate if needed.
__________________
1973 Mustang Convertible
460 D0VE-C Heads w/CJ size valves, Lunati voodoo 227/233 cam, Edelbrock performer rpm manifold, FPA headers, Holley 950 HP carb, C6 w/2500 stall converter, 3.25 trac lock
TommyK is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 06:32 AM   #3 (permalink)
Senior Member
 
dalorzof's Avatar
 
Join Date: Jan 2003
Location: Brisbane, Australia
Posts: 5,090
Default

Mechanical advance vs. vacuum advance article - Pro-Touring.com
__________________
"True terror is to wake up one morning and discover that your high school class is running the country."
Kurt Vonnegut


8R03S : 76A I 2A 15M 72 5 U
8R01S : 65A B 2A 28M 72 7 5 - Factory GT
8R01C : 65A M 2A 01E 72 2 W - CS/GT
8F01X : 65A I 2G 20E 24 1 U - EXP500 to-be

http://i64.photobucket.com/albums/h1...pr_07_tiny.jpg
dalorzof is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 08:54 AM   #4 (permalink)
Senior Member
 
Join Date: Mar 2001
Location: Ontario
Posts: 9,359
Default

That is a great article
__________________
Paul
1965 Mustang 2+2
pprince is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 09:56 AM   #5 (permalink)
Senior Member
 
68RCodeConv's Avatar
 
Join Date: May 2003
Location: Houston TX - I drive mine.
Posts: 9,578
Default

I'm running straight mechanical advance on two of my cars and they run just fine BUT they would get better gas mileage with vacuum advance on them.
__________________
John Bednorz

1967 Shelby GT350, dark green, 347 stroker, 5-speed, inboards, #2206
1973 Mustang Convertible, white/white, black stripes, Q-code (351C-4V), ram air.
1968 1/2 428 CJ convertible, R-code, red/deluxe red, auto, finally finished.
"If you find the car of your dreams, ignore the price guides and pay whatever you have to in order to get it."
68RCodeConv is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 10:25 AM   #6 (permalink)
Member
 
Join Date: Jan 2010
Location: Saugus, Ma.
Posts: 47
Default

One thing I can tell you about the Mallory Uni-lite unit is Do Not leave the ign. key on for any length of time. I have that system on my 550 h.p. big block Chevelle mechanical advance and I accidentally left the key on and burned out the eye. A $95 mistake. I was recently told that you can buy some type of resistor to insall in line to prevent this from happening. Good luck with it. For my newer project of my recently purchased 65 Mustang fastback (With the help of a lot of VMFers ) I pulled out the Accel dual point dist. (which was also mechanical advance due to the radical cam) and went with the Pertronix 2 dist. and Flamethrower 45,000 volt coil drop in unit and am very happy with it. Good luck.
Chris.
Attached Images
File Type: jpg DSCF9381.jpg (92.1 KB, 2 views)
Chevelleguy is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 11:53 AM   #7 (permalink)
Senior Member
 
02Lightning's Avatar
 
Join Date: Jun 2003
Location: Dayton, Oh.
Posts: 1,524
Default

How would you define manifold vacuum or ported vacuum? Manifold is obvious but what do you mean by Ported vacuum?
__________________
Greg

1969 Mach1 428 4-speed 3:89 gears,
31 spline posi "N" case, ported edelbrock heads,
full length headers, 292H Comp cam, 750 holley.
Born July 17, 1969

2002 SVT Lightning, Supercharged
1959 Alfa Romeo Giulietta Spider Veloce

http://thumb7.webshots.net/t/55/855/...7OAFnSf_th.jpghttp://thumb8.webshots.com/t/24/24/9...8cudqTY_th.jpghttp://thumb7.webshots.net/t/50/750/...7lmBPYC_th.jpg
02Lightning is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 12:32 PM   #8 (permalink)
Member
 
Join Date: Dec 2009
Posts: 78
Default

I don't recommend the Unilite. Just way too sensitive and replacements is really spendy. They are no more accurate than a magnetic pickup. The Mallory magnetic is a great dizzy and really tough. Get a vacuum advance unit. It will perform better, plus better milage.

You might take a look at the Pertronix brand dizzy. They are very well built and have a bearing at the upper shaft. I don't recommend the MSD units as they have dissimlar metals in the advance unit and corrode quickly amking the advance sluggish or not work at all.
Blubaron is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 01:06 PM   #9 (permalink)
Senior Member
 
JohnTheTruckGuy's Avatar
 
Join Date: Dec 2007
Location: The woods of the Finger Lakes, western NY
Posts: 193
Default

Quote:
Originally Posted by 02Lightning View Post
How would you define manifold vacuum or ported vacuum? Manifold is obvious but what do you mean by Ported vacuum?
"Ported" = at or above the throttle butterflies

"Manifold" = below the throttle butterflies

Ported vacuum is a creature of the emissions monsters. IIRC, it's more effective at keeping N-oxides down while at or near idle, as it controls ignition more tightly in low-opening transition states. Somebody with a clue could probably explain it better than that.
__________________

http://img232.imageshack.us/img232/5...tangwgidn7.jpg

"It's always better to be shot out of a cannon than to be squeezed out of a tube" - Hunter S. Thompson
JohnTheTruckGuy is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 02:11 PM   #10 (permalink)
Senior Member
 
TommyK's Avatar
 
Join Date: Dec 2005
Location: CT
Posts: 1,005
Default

Quote:
Originally Posted by pprince View Post
That is a great article

It says "author unknown" but it was written by Lars Grimsrud.
__________________
1973 Mustang Convertible
460 D0VE-C Heads w/CJ size valves, Lunati voodoo 227/233 cam, Edelbrock performer rpm manifold, FPA headers, Holley 950 HP carb, C6 w/2500 stall converter, 3.25 trac lock
TommyK is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 02:12 PM   #11 (permalink)
Senior Member
 
Hemikiller's Avatar
 
Join Date: Jun 2002
Location: Killingworth, CT
Posts: 7,680
Default

I use ported vacuum on all of my cars. A big advantage is that you get a little boost of timing right off idle at throttle tip-in, this helps improve driveability and fuel mileage. I've tried a manifold vacuum setup several times and I just don't like the way it feels or drives.

You'll get the usual feedback of "vacuum advance is for smoggers" and every mutation of that statement you can think of. Simply put, if you have a stock or mildly warmed over engine, then you're just wasting a whole lot of fuel if you don't use vacuum advance.

My ignition setup of choice for a street cars is a Ford Duraspark dizzy with an MSD box and coil. Dead nuts reliable and if the dizzy goes bad, parts are as close as your local auto parts store.


-
__________________
Nothing worthwhile is ever quick, cheap or easy, those that can't do, complain

71 Mach 1

HOLLEY TECH PAGES
FORD OE TACH HOOKUP FORD OE TACH HOOKUP w/MSD (pg 7)
Hemikiller is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 05:05 PM   #12 (permalink)
Senior Member
 
JohnTheTruckGuy's Avatar
 
Join Date: Dec 2007
Location: The woods of the Finger Lakes, western NY
Posts: 193
Default

Quote:
Originally Posted by TommyK View Post
It says "author unknown" but it was written by Lars Grimsrud.
I thought it looked kinda familiar. Lars and John Hinkley (aka John Z), both Corvette guys, have written a whole series of articles on engine topics (particularly ignition) that are really textbook quality. John is a retired engineer from Chevrolet, and I believe that Lars background is similar.
__________________

http://img232.imageshack.us/img232/5...tangwgidn7.jpg

"It's always better to be shot out of a cannon than to be squeezed out of a tube" - Hunter S. Thompson
JohnTheTruckGuy is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 06:18 PM   #13 (permalink)
Senior Member
 
dobrostang's Avatar
 
Join Date: Oct 2009
Posts: 1,313
Default So many loose ends

This brings up something else I have put off. I have both a MSD dist and several Ford distributors. I have been running a Ford because someone spent a lot of money getting it set up right for the motor it came with (I still run it). When ever I try to hook up the vacuum advance the engine dies. I have tried several distributors (I have a box full) and its always the same thing. I tried every port on my 4150 and my intake manifold they are all the same. So I run without vacuum advance. I would love to hook it up if someone understands what I'm doing wrong. Wouldn't mind a little better gas milage...

Performer RPM cam and intake - 650 Holly 351W.
dobrostang is offline   Reply With Quote Quick reply to this message
Old 03-09-2010, 08:31 PM   #14 (permalink)
Senior Member
 
Join Date: Oct 2009
Location: chelsea, quebec
Posts: 324
Default

So vacume advance it is, my next question is if I go with the pertronix flame thrower, do I need to get one of those ignition modules or can i just drop it in hook up the wires set my timming and go.
Jays_68_302 is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Vintage Mustang Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are Off


Powered by vBadvanced CMPS v3.2.2

All times are GMT -4. The time now is 04:11 AM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.3.2 ©2009, Crawlability, Inc.