Distributor spring change

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carkindaguy

carkindaguy

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I was thinking about changing the springs in my mallory distributor
and I am looking for some helpful advice. Has anyone done this? What
kind of results did you get? My goal is more bottom end power.
 
It all depends on what's in there now. Without doing a plot of the current advance curve, you are just guessing, and ya just might make things worse

Most performance / Mallory / Accel distributors already come with a "performance" oriented curve, usually much better than a factory smogger right out of the box
 
Buy the spring kit. I believe it comes with curve ranges and ideas. If you want to post as much detail as you can on your current engine/car package we can toss some ideas out. Just be aware the suggestions may be very different from each other...lol.
 
It came with the spring kit so i already have that. The manual says it is equipped out of the box for a stock type setup. The manual shows me some charts with the different timing curves for the different spring setups. My setup is a 360 duster, ported eddy heads, lunatii voodoo flat tapped cam. 10:5.1 comp, 727 torqueflight, 373 dana 60, street car. 450-500hp. 750 holley double pumper. Fresh motor only 1000 miles on it. 2500 stall converter. I trying to get a little more out of the 0-60mph. I thought maybe putting in the lighter spring for a faster timing advance might help a little. If im wrong there is more options. And if nothing helps i can always put it back to the factory spring setup. All for free. Just want to know if any one has played with this and what kind of results have come from it? Thanks
 
With that build you want a fast, short curve. I'd start with no more than 18* crank degrees in the dist, and maybe start with the second to lightest springs in the kit.

Play with it a little to see where you are. Try about 36* total advance, which with 18* in the dist will give you an initial of about 18 initial.

If it kicks at the starter or pings at part throttle, you'll need more spring and or a longer curve.

If it tolerates it well, try the light springs.

"Back when" I ran a tach drive dual point in my RR with a 480 lift erson cam, I ran the thing for awhile with NO springs. The drag on the points pulls the advance back for starting, and when it fires, it's "all in." Back then, I ran 38-40* total advance. Better fuel, no ping.

Without running the thing on a dyno to optimize it, you are just guessing.
 
..i have tried different combinations.
..2 pink and you'll be all in at about 1800 rpm and the throttle response is noticeable
..the charts are quite close
 
With what you have, and assuming the quench was built into it - I'd say similar to 67's idea. 15-18° initial, 18-20 centrifical for a total around 38°. Have the curve start coming in around 1800, and be "fully in" by 2400. Also remember - always set timing first, then adjust the carb. Once the curve's set you'll want to look at idle vacuum in gear and get the right power valve(s) and then jet it.
 
How do I do it? For a street car - I take the vacuum reading at idle, in drive and write it down. Then I tape a vacuum gage hooked up to manifold vacuum to the windshield and drive around with it, noting what the vacuum is at cruise, light throttle accel, etc. Then I take those numbers and make a choice based on what they are. Depending on the package, usually a valve between .5"-2" lower than the idle vacuum level is what ends up in there. I also find by doing it this way I rarely have to realy mess with the squirtors or pump cams.
Some people use 1/2 the vacuum number (Holley will tell you both 2" under, and 50% of the vaccum number) Some guys say plug it and jet up 8 sizes for each valve. A lot depends on the carb, your location, and your package... and your tuner's experience. Carbs can be like cooking - some chefs do things differently from others.
 
well i had my timing checked yesterday by a mopar guy. omg it was so far off im embarrassed to say. but as i was driving i now noticed that with a little throttle there is a sound like something flapin around by the front of the tranny. iv done nothing to the distributor yet. timing is now at 35 full advance. any ideas???
 
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