Hello, y'all

The following was noted with my 727 auto with a 2400 stall convertor, just installed.

I am in the midst of a recurve study. I replaced a Pertronix dizzy system firing a stock coil. I replaced it with a NOS Mopar electronic dizzy feeding a MSD6A system with Blaster 2 and MSD8920 tach adapter.

The Pertronix worked great, engine easily revved to 4,000 just sitting in neutral in garage and over 2500 rpm in Drive I absolutely could not hold the vehicle from creeping even while applying both the parking brake.

I put in the aforementioned MSD system. NOS dizzy has a 13 governor and 7 vac can, but vac can not hooked up. Imagine my surprise to find that in Drive the MAXIMUM rpm possible with gas to floor was 2300! Easy to hold with light foot brake pressure, parking brake not even on. Dizzy set at 10 BTDC, advances nicely.

Is this what "stall" means? No creep, you just wind up and slingshot away at that rpm?

Any ideas why a Pertronix seems to yeld much more pull than a MSD system?

I now have three wiring systems tucked in for side by side comparison..one for Pertronix, one for Mopar electric dizzy with MSD, one with Mopar elect. dizzy and GM HEI module. I set them up for quick interchange for comparative study on a dyno, but first I want to understand what happened as described above. Any ideas anyone?

Thanks
rock
'64d100

You used the same distributor for both scenarios, right? No swap.

-D.Idiot

looks like he used a NOS mopar eletronic, u cant use petronix AND msd hei. petronix has dwell as well as trigger, NOS dizzy is just a trigger and needs the box for dwell on coil.
my guess is different advance in the two dizzys, giving them diff power peaks.
eh? eh?

_________________
'72 Valiant DD for over a decade-225-Disc brakes, big T-bars, big Sway bars f/r, carter bbd/super six, GM HEI, 2- 12" subs in trunk, 1000w amp...
'77 cherokee cheif widetrack-360-33x12.5 tires-no lift. keeps driveway dry-project/backup DD/mudder

1. Why do you need the tach adapter?
2. Did you try changing the polarity of the distibutor pickup?

I have a feeling the timing is late.

_________________
Joshua

i dont know, my car barley ran wit the wires swapped

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'72 Valiant DD for over a decade-225-Disc brakes, big T-bars, big Sway bars f/r, carter bbd/super six, GM HEI, 2- 12" subs in trunk, 1000w amp...
'77 cherokee cheif widetrack-360-33x12.5 tires-no lift. keeps driveway dry-project/backup DD/mudder

Thanks guys,

Always good to see thinking from a distance. First, yep, two dizzys, cause as Dank10 says, Pert. module is wired to ignition different than the Mopar electonic trigger. Then, you need the tach adapter with some tachs if using MSD because the trigger signal from some tachs won't signal a MSD...mine is a Sunpro, and they need the adapter.

Oddly enough to me, it made no difference what the polarity of the NOS dizzy wires to the MSD was in terms of running, yet with the GM HEI module it was critical...run or not run.

Third, I took apart the Pertronix dizzy after seeing your replies and found I had brazed the governor to make it a 9.8...and the one in the NOS Mopar with the wimpy torque was a 13, and had a light purple spring and a green heavy spring. I am gonna braze up a 9 and put in the NOS.

I also used different dizzys for two other reasons: (1) I really didn't want to take apart a sweet performing Pert. unit and (2) because I want to build up a collection of different dizzys with different curves to pop in for different demands.

I want about a half dozen with different known curves to "plug and play" with. Ultimately I would like to buy the dyno time to create a table of my known ignition types' combinations vs. HP X rpm. (Even though I kow Slant Six Dan is almost certainly dead on right when he says there is almost no difference between GM HEI module and MSD, I am curious to put a number to the difference on my engine.) I have been interested in this problem since Slant Six Cecil began writing about recurving about 4 years ago and my thinking is a derivative of his, Emsvitil's, Joshie's and Rob's...just a slant obsession!

thanks again,
rock
'64d100

wish i could find the crazy graphs of curves someone made that was a good read, u should search it

_________________
'72 Valiant DD for over a decade-225-Disc brakes, big T-bars, big Sway bars f/r, carter bbd/super six, GM HEI, 2- 12" subs in trunk, 1000w amp...
'77 cherokee cheif widetrack-360-33x12.5 tires-no lift. keeps driveway dry-project/backup DD/mudder

Talking about this thread......

http://www.slantsix.org/forum/viewtopic.php?t=13264

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

I recurved a 15 in as much spring swapping etc could do this - Marvelous lots of torque


NOW I assume that i could use a 11 or smaller I could use more initial advance......... better response perhaps.......

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Regards,
Fanie Gerber
It's never junk, it's just a part you're not currently using

http://www.valiant50.co.za
Just say I own a few Mopars

muhahahah, ya, that was good work you did. are you guys gettin these spring kits at parthouses or specialty??

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'72 Valiant DD for over a decade-225-Disc brakes, big T-bars, big Sway bars f/r, carter bbd/super six, GM HEI, 2- 12" subs in trunk, 1000w amp...
'77 cherokee cheif widetrack-360-33x12.5 tires-no lift. keeps driveway dry-project/backup DD/mudder

This question keeps being asked over and over.

You can use Mr. Gasket springs for a GM but I prefer finding old MOPAR distributors and robbing from them. I have been to our MOPAR dealer several times pleading for recurve kits. I keep getting the big NO! THEY ARE DISCONTINUED!

Our racers out here are forced to go after market distributors, instead using MOPAR products. Most of the guys use MSD billet distributors. Unfortunately none are available for the Slant Six.

If Doctor Dodge or others have any other options, please share them

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

I have a big jar full of distributor weight springs... that is where I go for the ones I need.
DD

It seems that the heavy springs with the elongated loop are the tough ones to find. What would be the possibility of finding a manufacturer for those? Would they be needed by small block and big block builders as well as slanters?

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

I have not found any mfgs. yet. The Good Doctor suggested we start collecting them from older big block distributors.
If a mfg. was found, they could be used for all engines including the SL6.

There are two philosophies in recurving.

One is use any spring you can find and weld up the govenor slots to limit the throw. This is trial and error for most of us since a matrix or table has not been published on the forum yet for what length slot yields a given mechanical timing. This is what many racers do. If a spring breaks the weight is limited by the slot.

The second is to recurve using MOPARS original intent. Use a long slotted govenor and a heavy secondary long, medium or short looped spring to limit the throw. The fine tuning option is to rotate the spring pegs for the desired effect. This gives you the initial hit by 2000 rpm and then an extended boost of a few more degrees after 2500 depending on the length of the loop and and wire gauge of the spring. The initial hit is governed by the weight of the primary spring. It is real nice for cruising and getting a little more mileage out of your ride. Coupled with the a long throw vacuum advance you can get some real good mileage.

This is how I got my SL6 to wake up and provide a very peppy response. It will also break the tires loose if you stab the throttle. It is no longer a slug, pressing down on the accelerator waiting for something to happen.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG