Distributor spring kit

[Blackhawkxx]

I didn't think the timing advance was coming in quick enough on my 78 302 Cobra so I got a spring kit and ripped it apart tonight. I thought I would post up some pics in case anyone else was interested in doing the same.
Turn your motor crank until the balancer points to TDC and the distributor rotor points to #1 spark plug wire. Mark dist housing and block and also plastic dist housing to rotor so you can put things back in the same place. Pull dist and put it in the vise.

Remove vacuum can by removing 2 screws and the C clip on the arm.
Remove the reluctor wheel by putting two large screwdrivers under each side toward the center (not on the points) and work the gear off without losing the little roll pin. Take your time and it will come off, just don't go cave man on it.

Then remove 2 screws holding plate on. You can move the pick up around to get to the screws.

Now you can see the springs that you want to replace and also the total number of centrifuge advance your dist is set for. The latter one can be changed, my is on the 15 slot which will give you 30 degrees plus the initial advance.

Springs changed ready to go back together.

The springs I used.

 

[2Blue2]

I like this.
very interesting.
You had a heavy and a rusty and now 2 light, right?
Why did you feel it was slow?
hows it feel now.
Can you tell seat of the pants style?

 

[Blackhawkxx]

I like this.
very interesting.
You had a heavy and a rusty and now 2 light, right?
Why did you feel it was slow?
hows it feel now.
Can you tell seat of the pants style?

The rusty and heavy springs are the factory original ones as I have never been in the distributor before and yes, the two light ones are in it now. From what I have read, this motor likes full timing in at about 2,500 rpm and it was much higher from the factory. Due to other things going on and rain, I didn't get to try it until tonight and it was a short ride, not enough to get the full picture. It feels good but I'm still going to play with the initial timing more to see if I can tweak a little more out of it. I figured for $8 for the springs, it would be worth it to try.

 

[extra_stout]

because you use the 15L slot you have 30° of mechanical advance. with knock starting at around 34-36 you do not have to many options with timing. Around 35° full mechanical advance at 2500 RPM minus 30° is around 5° initial advance.
You can reduce the 15L slot by welding and grinding or you put a piece of a small hose that fits over the finger and fix it with heat shrink.
I did the welding/grinding route and this calculation;

Slot Number​	degrees centrifugal advance ​	Slot Width​
​	​	in inch​	in mm​
8L slot​	16​	0,358​	9,0932​
9L slot​	18​	0,384​	9,7536​
10L slot ​	20​	0,41​	10,414​
11L slot​	22​	0,436​	11,0744​
12L slot​	24​	0,462​	11,7348​
13L slot​	26​	0,488​	12,3952​
14L slot​	28​	0,514​	13,0556​
15L slot​	30​	0,54​	13,716​
16L slot​	32​	0,566​	14,3764​
17L slot​	34​	0,592​	15,0368​
18L slot​	36​	0,618​	15,6972​
19L slot​	38​	0,644​	16,3576​
20L slot​	40​	0,67​	17,018​

 

[extra_stout]

I had two 302 both had in the end a DIY 10L to 11L slot with the light springs and an inital advance of 10-15°.
Detecting knock by listening is important. For saftey you can pull the vacuum advance hose and plug it on the engine side tight with a screw). Than you can test the mechanical/initial advance and after tuning that, you can set the vacuum advance (done by preload of a hidden screw inside the vacuum advance hose connector).
In my opinion its worth the work

 

[2Blue2]

I figured smog motors knock early but if it had a mild cam then the distributor would need recurving.

Now there looks to be a piece of hose or bumper on the tang now by the 15 mark is that factory?

 

[extra_stout]

I figured smog motors knock early but if it had a mild cam then the distributor would need recurving.

Now there looks to be a piece of hose or bumper on the tang now by the 15 mark is that factory?

yes, that rubber piece is stock. Something like a vacuum hose could fit over that

 

[Blackhawkxx]

On a stock motor, they won't take much advance but with my cam and heads plus I run 93 octane gas, I detected no pinging. I did back out the vacuum advance earlier and it stopped any pinging. There is night and day difference between tuning a stock 302 vs a built one. That being said, I'm not done playing so we will see.
Edit to add: I have a timing tape on the balancer and does look like there may be too much total but it's hard to read accurately on this motor plus I have read that the 15 degree (30) slot actually gives more than stated. I was shooting for about 38 total for my combination. I may take it back apart to limit the CV advance.
Here is a excellent piece about the subject.
https://vb.foureyedpride.com/showthread.php?22229-The-Ultimate-Duraspark-Distributor-Timing-Guide

And from that guide:

"Dyno testing has shown that most small block Fords with 9:1 to 9.5:1 compression make peak HP with 38-42 degrees total advance. Engines with 9.5:1 - 10.5:1 run best with 35-38 degrees total, and above 11:1, should not go higher than 35 deg. total."

 

[extra_stout]

Seems like you did your research. I just wanted do point out, that it needs testing and listening to knock ;-)
I like to have as much initial timing as possible... Thats why I like to be in the 10L to 11L range.
I tune my engine for low RPM torque (GT40p heads milled to raise compression a bit, stock explorer cam, aggressive timing and a lot of carb tuning), thats what I like (perhaps I should by an BEV).

 

[Blackhawkxx]

Seems like you did your research. I just wanted do point out, that it needs testing and listening to knock ;-)
I like to have as much initial timing as possible... Thats why I like to be in the 10L to 11L range.
I tune my engine for low RPM torque (GT40p heads milled to raise compression a bit, stock explorer cam, aggressive timing and a lot of carb tuning), thats what I like (perhaps I should by an BEV).

I went ahead and took it back apart. Found a thin (not the thick stuff) vacuum line and added to the post to limit the advance a little. I don't think anything thicker would fit because it would rub on the dist housing. I'm happy with where the timing is now about 38 or so. Now to perfect some carb tuning.

I need to do a little clean up under the hood next.

 

[extra_stout]

I'm happy with where the timing is now about 38 or so. Now to perfect some carb tuning.

Nice to see that some makes pictures and responds to ideas.
From curiosity, where is your initial timing now?

Regarding carb tuning: I think i saw some testing with different air filters. And if I remember correctly your air filter limits gas flow... but I'm not 100% sure and I didn't find the article where they did this research.

 

[extra_stout]

Found it

View: https://www.dailymotion.com/video/x693421
Around minute 9

 

[Blackhawkxx]

Found it

View: https://www.dailymotion.com/video/x693421
Around minute 9

I love Engine Masters, one of my favorite programs but I have never seen that one, thanks. I run that filter because of hood clearance, not much else will fit with my intake. Also I have a hole in the hood so it is sucking cool air from outside rather than the very hot under the hood air.
From your video they found out that the carb likes air to go straight down and they thought that my air cleaner should support 350HP. In the past I replaced the foam in the filter with something that was less restrictive but over time started to deteriorate so I put the stock one back in. I guess it is time to revisit that again.

 

[extra_stout]

I think they found out that the mini filter 10x2 (?!) was less restrictive and should fit your hood.
We all know well about hood clearance issues with MustangIIs
Would be tragic to limit your genius heads...

 

[Blackhawkxx]

I think they found out that the mini filter 10x2 (?!) was less restrictive and should fit your hood.
We all know well about hood clearance issues with MustangIIs
Would be tragic to limit your genius heads...

I really don't think anything else will fit as mine (which is about the lowest) sticks through the hole in the hood a little.
I don't think they tested a 10 x 2. Maybe I should do a salad bowl like they did.

 

[LILCBRA]

Probably not a fair comparison, but I ran that small filter on my engine when I first got it together - but I've never ran a stock scoop. There was a time I had the Cobra Jet scoop and that was all that would fit through a small hole that I had cut in my hood. I then went with a larger scoop from an 82(?) GT and cut a larger hole to accomodate a larger filter. Looking back, I think that small filter might work with the stock scoop but it might be pretty close.

From this:

To this:

What would be great is if someone produced a filter top for the small filter - then it wouldn't be so restrictive....

 

[extra_stout]

Maybe I should do a salad bowl like they did.

I would love to see that!
I don't have a solution for you. I run a dropped air filter with 14x3 element that just fits with the scoop I have. But I think the dropped air filter doesn't work with your distributor. I run a 66 mustang equivalent distributor with the small cap...

 

[Blackhawkxx]

I think with less restrictive foam, it will flow plenty enough for my little 302 plus pulling cool outside air has to worth a few HP over hot underhood air. Way back when I still had the stock air cleaner on it, I put flexible dryer hose over the end of the air cleaner snorkel run down by the air dam to force air in at speed. Always looking for cheap HP.

 

[85GTStangGuy]

What would be great is if someone produced a filter top for the small filter - then it wouldn't be so restrictive....

K&N has smaller filtered top air filters....

Complete 9" air filter with filtered top:
Amazon product ASIN B00062ZMCS
View: https://www.amazon.com/gp/product/B00062ZMCS/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1
11" filtered top (note: this is the top only):
Amazon product ASIN B00029WY4O
View: https://www.amazon.com/gp/product/B00029WY4O/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

 

[LILCBRA]

K&N has smaller filtered top air filters....

Complete 9" air filter with filtered top:
Amazon product ASIN B00062ZMCS
View: https://www.amazon.com/gp/product/B00062ZMCS/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1
11" filtered top (note: this is the top only):
Amazon product ASIN B00029WY4O
View: https://www.amazon.com/gp/product/B00029WY4O/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

Didn't realize they were available....

Then again, I never really looked for anything in those diameters either.