distributor curve springs?

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joshua dewitt

joshua dewitt

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question to anyone who has done this....
got the kit from FBO... his ignition box, no ballast resistor, petronix coil, spoke to don, stated to use the 18 degree slot, base at 16 and 30 total IDLE WITH FULL MANIFOLD VACUUM. NOW ADJUSTED VACUM POD TO @5 inch lbs of pull.... stated to have advance in around 3K +/- 500 rpm..... but never stated which springs to use..... the dual heavy, dual medium, or dual light. .... or combination of 1 heavy, and one medium or light... I have a stock dodge standard, not elongated, and mr. gasket light and revs awesome, but won't idle well. took it out to re-curve properly. have access to distributor machine, just trying ot get a clue where to start my spring weights for first time,,,, haven't heard back from don... any suggestions.....
73 dart swinger full body car, @ 3K lbs 318 build 0 decked 9:5/1 compression, 93 octane, 302 casting heads, air gap intake 600 cfm, 100 shot nos.. latter on..... a904l/up.. and 3:50 gear with 28" tall rear tire... anyone have done this?
 
I would start by thinking the idle might be too high for that combination of springs, because what you did was what a lot of people use.

An idle above 800 might be letting the weights move too much.
 
I DO NOT LIKE using full manifold vacuum, but think what you are doing here

If you set initial timing (vacuum unhooked) at 16, and depending on what cam you have, and depending on what vacuum can you have, the think will be sitting there at idle with 16 PLUS whatever is in the vacuum can!!

I know he claims "that works" but I don't know specifically what to tell you. Manifold vacuum is not how I'm used to thinking.
 
For Street Duty
-I also, would recommend to swap the vacuum source for the V-can to Timed / Ported source, AND to make sure the V can is not working at all, at idle.
-Then I would start with two medium springs, in an effort to delay the "all-in" timing to 3500ish.What is important is to not bring in the advance too fast.If you have access to the dizzy-machine, just slam in whatever springs it takes to hit the target. If the engine accepts this with no detonation,then, at some later date,and, on the street, I might try to bring in the timing a little quicker. But if you do this;just don't bring in the N2O until further up the RPM band.N2O will kill the pistons real quick with too much timing.
-I would loosen up the V-can spring-preload, so that the V-Advance was all in asap.But I would experiment with the rate later, after the initial/power numbers,and the rate of of mechanical advance,are finalized;until then, I would leave it disconnected.
-The 16/30 setting is probably good for running N2O, but It is terrible for street. I would suggest a 18/34,or 20/36 street setting. Then,at the track; back the timing up and defeat the V-can.
-The 18/34 with a fast 20*can will pump up the low speed part throttle timings. This will,smoothen the torque delivery, and make the teener behave bigger than it really is, and return some good fuel mileage as well. It is the only way to get timing of 48* or more, at cruising speed, which is what the engine desperately wants.
Make sure your T-port is synced up, and depending on the cam, 800(like TB says),or less, is a good idle target.

The trick for a streeter is to give the engine as much timing as she wants, under all conditions, and not one single degree more. In fact two or three degrees short is better than 1 degree too much. This becomes a real test-of-patience, as it is or sometimes becomes, a moving target.
Some guys crank a ton of initial into it, cuz the engine accepts it. But the power-timing is more or less fixed in stone within a degree or two. Then it becomes a battle with dialing in the rate of advance. If you bring it in too slow, one might think you'd be missing some power. But if you bring it in too fast, and she gets into detonation, you get to start over. For this reason, I like to start with a slow curve, and perhaps with a little less initial, and sneak up on it over time.This way has three advantages.#1) the engine will live,and #2) you get to know your engine, and #3) you get to see how the mechanical curve interplays with the vacuum curve.
When you start to zero-in on the various numbers your butt-dyno, and ears may no longer be accurate indicators of what the engine is doing, especially if you have been doing some carb work at the same time. So......start sneaking upon her.
 
For some stupid reason I completely ignored the manifold vacuum part, as that could throw the initial timing way up there at idle if it was set at 16 initial and THEN hooked up.
Duh! :D

I have some way distracting stuff going on around here lately, sorry.
 
I'd probably go with one light and one medium to start. I might also shorten the slot a bit once you find out how much initial you can get away with when warmed up.
 
If you are setting up for street, and see the N0S as a later-on add-on, I highly recommend you set your timings all up for street, and get a timing controller for the Nitrous later, when you add that on.You will have a much more fun-to-drive teener. Yanking 6 or more degrees of power timing out of it, will make for a sluggish ride, when NA. That teener in a 73 Dart full body, (which is more like 3600plus with driver), is not so powerful that it can afford the timing sacrifice, especially with a lumpy cam.
-That is what post 4 is about.

If you are setting up for a track car, then just ignore me, but I did notice this time that I'm not in the racer's forum.
 
well the car has been lightened some, no heavy bumpers, or heavy seats... lighter ford axle, weld drag light wheels, have nos there, came as a kit with the fuel pump, will add later... and yes once dialed in, will add the pertronix second strike with a timing controller once that works, still getting the sanden compressor to line up with pulleys better to avoid belt squeal. as did my factory v-belts did, ( hate that). don was saying from fbo do have advance all in at 3000-3200rpms... and to start with the tow silver springs in his kit. and suggests using the slot for 16 degree... just feeling what others had done out there. my Saturday project when I get home after work.
 
got the distributor curved with the silver springs and the plate for 18 degree as don from fbo suggested... and once I get my new wires made I can retune everything...
just finished installing billet w/p and crank pulleys... today..
 
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