Distributor spring kit

Blackhawkxx · Jul 30, 2023

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 · Aug 2, 2023

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 · Aug 2, 2023

2Blue2 said:
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 · Aug 3, 2023

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 · Aug 3, 2023

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 · Aug 3, 2023

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 · Aug 3, 2023

2Blue2 said:
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 · Aug 3, 2023

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 · Aug 5, 2023

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 · Aug 5, 2023

extra_stout said:
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 · Aug 6, 2023

Blackhawkxx said:
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 · Aug 6, 2023

Found it
Around minute 9

Blackhawkxx · Aug 6, 2023

extra_stout said:
Found it
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 · Aug 6, 2023

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 · Aug 6, 2023

extra_stout said:
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 · Aug 7, 2023

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 · Aug 7, 2023

Blackhawkxx said:
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 · Aug 7, 2023

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 · Aug 8, 2023

LILCBRA said:
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
11" filtered top (note: this is the top only):
Amazon product ASIN B00029WY4O

LILCBRA · Aug 8, 2023

85GTStangGuy said:
K&N has smaller filtered top air filters....

Complete 9" air filter with filtered top:
Amazon product ASIN B00062ZMCS
11" filtered top (note: this is the top only):
Amazon product ASIN B00029WY4O

Didn't realize they were available....

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

Distributor spring kit

Blackhawkxx

Advanced Member

2Blue2

will be trying this sex one when I can find it

Blackhawkxx

Advanced Member

extra_stout

extra_stout

2Blue2

will be trying this sex one when I can find it

extra_stout

Blackhawkxx

Advanced Member

extra_stout

Blackhawkxx

Advanced Member

extra_stout

extra_stout

Blackhawkxx

Advanced Member

extra_stout

Blackhawkxx

Advanced Member

LILCBRA

I wish I didn't have all of these balls in the air

extra_stout

Blackhawkxx

Advanced Member

85GTStangGuy

LILCBRA

I wish I didn't have all of these balls in the air

Similar threads

Distributor spring kit

Advanced Member

will be trying this sex one when I can find it

Advanced Member

will be trying this sex one when I can find it

Advanced Member

Advanced Member

Advanced Member

Advanced Member

I wish I didn't have all of these balls in the air

Advanced Member

I wish I didn't have all of these balls in the air

Similar threads

Privacy & Transparency

Privacy & Transparency