FYI FORD - MustangSteve's Ford Mustang Forum
The Internet's Most Knowledgeable Classic Mustang Information
IF YOU HAVE A QUESTION ABOUT CLASSIC FORD MUSTANGS, YOU HAVE COME TO THE RIGHT PLACE!
MustangSteve has over 30 years of Mustang experience, having owned 30 of them and restored several others. With the help of other Mustangers, this site is dedicated to helping anyone wanting to restore or modify their Mustang.... THERE ARE NO DUMB QUESTIONS!!!!!
Visit MustangSteve's web site to view some of my work and find details for:
FYIFORD Contributors' PICTURES - Power Brake Retrofit Kits for 65-66 Stangs - Classic Mustang FAQ's by MustangSteve - How to wire in a Duraspark Ignition - Mustang Ride Height Pictures and Descriptions - Steel Bushings to fit Granada Spindles to Mustang Tie Rods - Visit my EBAY store MustangSteve Performance - How to Install Granada Disc Brakes MustangSteve's Disc Brake Swap Page - FYIFORD Acronyms for guide to all the acronyms used on this page - FYIFORD Important information and upcoming events

You are not logged in. Would you like to login or register?

8/07/2019 9:17 PM  #26


Re: Recurve distributor DURASPARK-2

The instructions you show do not match the instructions from Summit for the part number on the box.  Try this link and compare the two.  Seems like the one from Summit makes a lot more sense on the springs.

https://www.summitracing.com/parts/crn-99607-1/media/instructions

 

8/07/2019 9:23 PM  #27


Re: Recurve distributor DURASPARK-2

6sally6 wrote:

I didn't use ANY of the stock springs! JUST THE TWO LIGHTEST SPRINGS.  Think about it this way. You want a spring just strong enough to pull the mechanism closed when you shut the engine off. (Easier for the starter to spin over if its not fully advanced.)  "Some guys" just use plastic tie wraps to lock the advance mechanism WIDE OPEN!  Just have a strong battery and good starter to crank the engine over. (more of a race application but just trying to explain how the mechanism works)
Just stay on track like you were on (and how we talked about). 2 lightest springs. Use a bushing of some type to 'limit' the TOTAL advance to no more than 38-40* at 2500RPM or so.   OR..use the 2 light springs and no bushings anf just limit your total to 36-40* when turning your distrib.and watching your timing tape with a timing light. The bushing deal would be better butt..........if you can't, go with what you got.
Did you say you had some type copper tubing to fit on post for a bushing?
The pic you sent me is as far apart as you need to take it.
DO YOU KNOW where I am talking about putting a bushing? If not.......say so.
6s6

 
Nah the bushing I have doesn’t fit but now I do have precise measurement of what tube size I need to look for .. 8mm OD and 5mm ID

I will try to find that somewhere .. and limit the 16L to 10L


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

8/07/2019 9:24 PM  #28


Re: Recurve distributor DURASPARK-2

GPatrick wrote:

The instructions you show do not match the instructions from Summit for the part number on the box.  Try this link and compare the two.  Seems like the one from Summit makes a lot more sense on the springs.

https://www.summitracing.com/parts/crn-99607-1/media/instructions

 
Those instructions do seems different.. the springs aren’t colored the way that the online one says though. Colors on the one I posted coordinate the springs in the package .

I will reconfirm though that’s they didn’t mix the boxes contents


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

8/07/2019 10:14 PM  #29


Re: Recurve distributor DURASPARK-2

Sent information to your email Gaba.
I can’t add images out here in my neck of the woods.
Nice documentation too. 👍🏼👍🏼

 

8/08/2019 4:46 AM  #30


Re: Recurve distributor DURASPARK-2

The instructions have it backwards.  They are saying to use the heaviest spring to bring the advance in soonest.  It should also be easy to look at the springs and tell which is lightest.  The smallest wire diameter will be the lightest spring.  Lightest springs will bring the advance in the soonest.  At what RPM it achieves full advance can only really be known by testing with a timing light.  The only reason to delay full advance would be if the engine was detonation sensitive, which if its low compression it likely isn't. 

Race cars run locked advance, and use a cranking timing delay in the ignition box to allow the engine to spin over easy and start. 

 

8/08/2019 6:05 AM  #31


Re: Recurve distributor DURASPARK-2

TKOPerformance wrote:

Race cars run locked advance, and use a cranking timing delay in the ignition box to allow the engine to spin over easy and start. 

Will going with lighter springs make the engine harder to start?
 


1964-1/2 D Code Coupe - 289 V8, 4 Speed Toploader, 3.00 ratio rear, Autolite 4100 Carb, 15" tires, Pertronix ignition
 

8/08/2019 6:26 AM  #32


Re: Recurve distributor DURASPARK-2

I am looking at various parts places and there seems to be a lot of options with distributor advance kits. Does anyone know what options best fit the Autolite distributor?
The adjustable vacuum advance is being recommended. Which one best fits the Autolite distributor?
Thanks,
 


1964-1/2 D Code Coupe - 289 V8, 4 Speed Toploader, 3.00 ratio rear, Autolite 4100 Carb, 15" tires, Pertronix ignition
 

8/08/2019 7:43 AM  #33


Re: Recurve distributor DURASPARK-2

Stevo wrote:

TKOPerformance wrote:

Race cars run locked advance, and use a cranking timing delay in the ignition box to allow the engine to spin over easy and start. 

Will going with lighter springs make the engine harder to start?
 

 
No.. centrifugal / mechanical advance starts after 800-1000 rpm..

Having too much initial advance will make it hard to crank though yes


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

8/08/2019 9:10 AM  #34


Re: Recurve distributor DURASPARK-2

Ok so I called crane cams! And read them the manual.. they admitted the manual was backwards ... so nice ! Lol

So he said , what he recommends is changing out both the springs to the lightest spring ..

The photo below shows you left to right heaviest to lightest springs .. bottom is the stock springs




By the way, the manual said that you may only need to change one of the springs (the heavier spring) with the light spring

Cause I have 6sally6 and cranecams telling me to use both light springs , I will go with that .

The copper (lightest) springs are about the same or teeny bit lighter than the light spring that the distributor had in it

I know if I have to go heavier I will start with changing one out to the stock light spring .

For now .. onward ... finding a tube ID 5mm and OD 8mm to fit the post to limit my 16L to a 10L


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

8/08/2019 9:46 AM  #35


Re: Recurve distributor DURASPARK-2

Gabba is correct.  So long as you have springs and the breaker plate can move mechanical advance will not affect cranking.  I was referring to when guys lock the advance fully advanced (full timing all the time).  Cranking difficulty would only be encountered in a typical street car if you went too far with base timing, but I've never had an issue with 12-15 degrees base so long as the battery, starter, and cabling is in good shape. 

I'd also advise changing both springs.  There's no point delaying advance in your application.

 

8/08/2019 10:25 AM  #36


Re: Recurve distributor DURASPARK-2

Soooooooo we all agree?!!!!!! Cool
I honestly don't know what my initial timing number is!  I set the total and let the initial 'fall-where-it-may'!
Even when hot and hot outside temp it spins over fine. Non-issue
6sal6


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

8/08/2019 11:35 AM  #37


Re: Recurve distributor DURASPARK-2

You’re doing great Gaba. This is something I have needed to do, but never got aground to it. Thanks for documenting.


John  -- 67 Mustang Coupe 390 5 speed
 

8/08/2019 12:32 PM  #38


Re: Recurve distributor DURASPARK-2

in the meantime, crane will continue to publish and issue their dyslexic manual...........nice catch Gaba.....
 

 

8/08/2019 2:35 PM  #39


Re: Recurve distributor DURASPARK-2

ok SO I went to Home Depot and picked up two tubes about 5/16" OD. (8mm) . One is polyethelene.. I installed the little cut peice but while it was hard poly , it wasnt hard enough and I wondered if this material will keep its shape enough in heat.. molding temperature of Polyethelene is 125F ... may not get that hot in the distributor but it may .. Here is the tubing I got ..


So , i finally ended up making a bushing out of a 5/16" bar of metal. The ID was 7/64th for whoever else wants to make one.. on the outside of the bushings had to have flat spots made in them as there isnt all that much space to fit a circular 5/16th bushing..



I have an extra if someone wants it hahahaha haha ;)



So now my 16L will be lowered to 10L with this.. here is a pic of a very crude but very functional setup Hey my first "fabricated" part!! here it begins LOL
 

Last edited by Gaba (8/08/2019 2:41 PM)


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

8/08/2019 2:41 PM  #40


Re: Recurve distributor DURASPARK-2

6sally6 wrote:

Soooooooo we all agree?!!!!!! Cool
I honestly don't know what my initial timing number is! I set the total and let the initial 'fall-where-it-may'!
Even when hot and hot outside temp it spins over fine. Non-issue
6sal6

I've contacted my pastor to see if hell froze over...

 

8/08/2019 4:15 PM  #41


Re: Recurve distributor DURASPARK-2

Is anyone able to give me a part number of a kit that I can order? I am ready to roll on this


1964-1/2 D Code Coupe - 289 V8, 4 Speed Toploader, 3.00 ratio rear, Autolite 4100 Carb, 15" tires, Pertronix ignition
 

8/08/2019 4:54 PM  #42


Re: Recurve distributor DURASPARK-2

Stevo wrote:

Is anyone able to give me a part number of a kit that I can order? I am ready to roll on this

Scroll up you’ll see it . I posted a pic of the part number ..

The bushing is something you’ll need to fab yourself ...

6sal has used a cut push rod section as bushing and it worked ..

Last edited by Gaba (8/08/2019 5:03 PM)


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

8/08/2019 4:56 PM  #43


Re: Recurve distributor DURASPARK-2

Filled the bushing with epoxy so it doesn’t teeter or twist and bind .


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

8/08/2019 5:10 PM  #44


Re: Recurve distributor DURASPARK-2

Can hardly wait for a tune and road test!
I suggested to Gaba a steel nut might work good too. Find one that the hole will slide over the post then the sides can be ground down to give the measurement you need!
The more we brainstorm the better this thing is.
6sal6


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

8/08/2019 7:07 PM  #45


Re: Recurve distributor DURASPARK-2

Gaba wrote:

Stevo wrote:

Is anyone able to give me a part number of a kit that I can order? I am ready to roll on this

Scroll up you’ll see it . I posted a pic of the part number ..

The bushing is something you’ll need to fab yourself ...

6sal has used a cut push rod section as bushing and it worked ..

Ah...  Crane Vacuum Advance Kits 99607-1 
Thanks very much!




 


1964-1/2 D Code Coupe - 289 V8, 4 Speed Toploader, 3.00 ratio rear, Autolite 4100 Carb, 15" tires, Pertronix ignition
 

8/08/2019 7:48 PM  #46


Re: Recurve distributor DURASPARK-2


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

8/08/2019 10:10 PM  #47


Re: Recurve distributor DURASPARK-2

Gaba's gonna be a mechanic before ya know it. Kudos to you Gaba for jumping into your Mustang with both feet. It ain't rocket science.


Bob. 69 Mach 1, 393W, SMOD Toploader, Armstrong  steering, factory AC.
 

8/09/2019 1:54 AM  #48


Re: Recurve distributor DURASPARK-2

Regarding the advice on using the light springs and being good to go, there's a reason they put the different springs in a performance recurve kit. If the light springs were all that were needed then they wouldn't bother with the medium and heavy springs. A mechanical curve depends on lots of factors, air density/altitude, cam overlap & advance/retard, static/dynamic compression ratios and so on. There is no one size fits all for this (and I wish there was!).

As with any modifications that are performance related, test test test to find the best!

 

8/09/2019 5:43 AM  #49


Re: Recurve distributor DURASPARK-2

No stock springs, replace them with the two lightest.  The mechanical advance and base timing in isolation don't really matter.  What you are after is total mechanical advance.  So if you need say 42 degrees of total advance and you have 32 degrees of mechanical advance because you are using the 16 slot then you simply set base timing at 10 degrees BTDC.

Like 351MooseStang said, there's no reason to bother with the medium or heavy springs in a stockish application.  The only reason to delay advance would be in a detonation sensitive application (high compression, big cam, etc.).  Timing in such an engine is much more of a balancing act.  I've yet to see a stock or mildly modified engine that would detonate if the advance was brought in too soon.  I mean, maybe if you used no springs at all or something, but in a normal setup that a sane person would try it doesn't seem to be possible. 

 

8/09/2019 8:58 AM  #50


Re: Recurve distributor DURASPARK-2

I have a 10.2 to1 351W w/ Erson HFII cam installed 4 degrees advanced, and have to run a medium and a light spring or I get spark knock at around 1800-2000 RPM at sea level, air temp above 70. It's brief if I am accelerating but I can bring it in and hold it there if I'm light on the throttle and under load in third gear, which is bad news if you aren't paying attention to it. Going with one medium delayed the advance enough to eliminate it, even at an air temp of 95. That's with 91 octane non-ethanol racing gas (as it says on my receipt to make me feel better about the price...lol).


Higher compression, tight LSA = heavier springs
Higher compression, wide LSA w/ advance = lighter springs
Lower compression, just about any cam = light springs

and so on and so on. Toss in the other variables and you can see that it's not so cut and dried for advance. Most of my work is in marine systems and you have to be very careful with modified timing curves on high performance marine engines and the constant loads they are under, so I'm a bit more tuned in to it than most mechanics are (no pun intended,,,lol). Bad timing in those situations costs big $$$ and will kill your reputation in a small shop, so you test, test, test...

Then you hand them the bill, the best part of the job!

 

Board footera


REMEMBER!!! When posting a question about your Mustang or other Ford on this forum, BE SURE to tell us what it is, what year, engine, etc so we have enough information to go on.