Dramatically better MPG with the DurasparkII

[Guest]

If you have a DuraSpark II distributor, you also have smog-control spark advance curves inside. All of the DuraSpark units came this way, to reduce hydrocarbons. Unfortunately, it also reduced MPG.
However...today's gasoline reduces the hydrocarbons for you, even more than the slow spark curve did. So, get a set of the Mr. Gasket #925D distributor springs and modify your distributor as follows:

1. Remove the lighter of the 2 springs in the DII and replace it with one of the #925D springs. DO NOT replace both springs with the #925D springs (more on that in a moment).
2. There is a support arm that holds the larger spring, on it's non-slotted end. Bend this arm in toward the center of the distributor, just 3/32".

This combination replicates the "police interceptor" distributor spark curve for the 200 I-6, according to a local "guru" who helped build these for Ford in the early 1980s. It causes earlier spark advance up to 1200 RPM, which then remains steady until 1800 RPM, when the secondary spring starts its advance. This "plateau" of early advance, limited by the 3/32" inward adjustment of the heavier spring, provides more torque at around-town speeds. Ths improves your MPG because you don't have to open the throttle as far to get the same speeds you were running before. You'll also notice better off-the-line pep and cold-running performance. Mine also starts a little better when hot, and the plugs stay cleaner. My in-town MPG rose from 16.5 average to 18.1 average over 2 tanks of gas, winter driving to and from work. I haven't tested the highway MPG yet, but I don't think it will improve from the 23+ I've been getting. I'll re-post if it does.

If you make the mistake of replacing BOTH springs in your DII with the #925D springs, you will get a SLOWER spark curve unless you extensively modify one of them to provide a "slot", like the heavier spring already has: but I found, even after that exercise, that the engine "hit the wall" at about 2200 RPM and would not accelerate well up hills. Adding in the heavier spring, but delaying its effect until 2000 RPM, did the trick: now it loves to rev, even on regular gas (my compression is about 9.4:1). The maximum advance is reached at 2600 RPM on my engine with this mod: before, the max advance was at 3200 RPM.

[JackFish]

I'd like to give this a try.
What will the effect be in combination with my valve timing in at 4* advance with the double roller chain?

[80Stang]

This is great info! Just in time for me to change my order for some springs. Thanks!

[76maverick]

That sounds great ! Will that mod work on a V8 dizzy ?

[CobraSix]

Looks like I have a new project to try and photograph and post...that is as soon as I find my photo card for my camera...

[kirkallen143]

Yes, and my points dist came stock with the two different sized advance springs. It also has the vacuum adv/retard canister.

Kirk

[70stangcoupe]

Is the Duraspark 2 the stock distributer that would have come on a 1970 250

[addo]

No, that would have been an Autolite or Motorcraft points unit.

[Linc's 200]

I'd like to give this a try.
What will the effect be in combination with my valve timing in at 4* advance with the double roller chain?

ZERO. The distributor turns independent of your camshaft!!

If you installed the new timing chain but NEVER loosened/turned your distributor, THEN timing would change.

[Guest]

inside the dura ll

maybe some one could give a line nice draw to this for howto .

[Griny]

Hey, "the66mustang" you gotta stop smoking man! read that package! lol

[64falcon200]

This page has nice info about recurving the DSII as well as dissasembly instructions, for those of us who want to be very sure we are doing things right

http://www.reincarnation-automotive.com/Duraspark_distributor_recurve_instructions_index.html

[Guest]

after a litte tuned and cleaned up .







smoking is bad , i know, whe die yonger , but the pakkage dont tel me howmuch younger i wil die , ahahah

[Linc's 200]

after a litte tuned and cleaned up .

Maybe too much clean!

[CaedesAd6]

is there any hope for the load-o-matic? will this same spring work for it?

[addo]

The Load-o-Matic is less than ideal. I would spend the dollars some do on Pertronix, getting a DS-II adapted to an early 170 instead. The parts store rebuilds frequently come with the wrong springs to begin with, so that is another thing to watch for.

[CaedesAd6]

Hey Adam, thanks for helping me... However, all I need to know now is how to modify the Duraspark II to fit an early (64) 170. I'm having all sorts of running problems with my new 78 head on my 64 block. I can't tell if it's the carb, or the ignition.
Thoughts?

Thanks in advance - Coincidentally - Adam... ^_-

[addo]

If you want to dispatch the Load-o-Matic (which I strongly urge ) there is no way known to avoid changing the oil pump. This is because the later distributors all used a 1/16" fatter oil pump drive shaft, which also must be bought or scrounged.

So - fit a standard oil pump to suit a 67-up 200 Mustang engine; no need for high volume pumps. Acquire the shaft, too. That's it for working under your motor.

For the new dizzy - you now must reduce the pilot diameter (that's the plain tip which has a recess in it for the oil pump drive shaft). It starts at 0.530" and must be turned down to 0.490 inches. A machine shop or engineer's works could do this in minutes. The shaft must be completely removed from the distributor to do this - not a hard job really.

Don't reduce the diameter right under the gear! That will make life difficult. Just stop a hair inside the edge of the driven gear. Reassemble, using new advance springs of the correct tension and install the unit. Don't forget the oil pump drive shaft.

All that now has to be done is the coil swap and wire splice, like any DS-II conversion.

It's a little bit of work, but nothing hard. I'm surprised Azcoupe doesn't always carry a couple of modified DS-IIs on the shelf...

[JackFish]

Speaking of dizzy mods, here's a tidbit I came across:
The cam plates can be modified by welding or cutting the gap, or slot.
The widths of the gaps are:
10* slot is .425"/10.8mm
11* slot is .450"/11.4mm
12* slot is .475"/12.1mm
You add or remove material on the side closest to the "pointy end".

[superbepro]

Hi:

Would the modification described by MarkP (Mr. Gasket #925D distributor springs and support arm bending) work on the larger 240-300 ci ford engines?

If it does I'll certainly do it to my truck. Thanks,

Raul

[MiniCJJ64]

Where did you but the Mr. Gasket Springs at

[addo]

I would suspect both Summit and Jegs carry the spring kit.

[jamyers]

Just an FYI - The above mod didn't work for me - it gave me way too much advance at part throttle and also at higher rpms at wot. The part-throttle could be dealt with by an adjustable vacuum advance, but the high rpm/wot could only be dealt with by either putting the "stock" (rebuilt dizzy) springs back in or by backing off the whole timing curve.

My DS1 dizzy (spec'ed from a '75 Maverick), is using the centrifugal advance slot marked 13, which means 26 degrees centrifugal advance (right?). I wouldn't mind shortening the slot to 20 degrees and putting the Mr Gasket springs back in if it didn't mean completely disassembling the dizzy and brazing up the slot.

What I did was put the original heavy/lighter springs back in, and then bend the tab for the heavy spring outward so that the lighter spring lets it advance up to about the 18-20 degree point (measured with my kid's plastic school compass), then it's got to overcome the heavier spring for the last 6-8 degrees. I only had to bend the tab outward 1/8 inch, so I'm not too far off from the curve I had, just restricted the higher-rpm advance a little more.

Initial advance is at 8 degrees (much more and it's on the edge of pinging on a hot day with the a/c on.)

It drives very well, nice throttle response at lower rpm, and it doesn't ping at all, even on hot days (95F).

[jamyers]

I forgot to add - anybody want my Mr Gasket springs? You can have them for postage, or for $50 and I'll throw in a set of 13" Moon wheel discs for free!

[MiniCJJ64]

I wonder how is the Spark curve on the new DUI Performance Distributor.

[Guest]

inside the dura ll

maybe some one could give a line nice draw to this for howto .

Well, I don't know how to draw on that, but the one you want to change is the lighter one, which appears to be the one on the left in this picture. The arm that supports the OTHER spring should be bent slightly toward the center of the distributor, so that the post in the advance plate rests halfway up the "slot" of the spring.

Sorry to be gone from here so long...

[Guest]

Hi:

Would the modification described by MarkP (Mr. Gasket #925D distributor springs and support arm bending) work on the larger 240-300 ci ford engines?

If it does I'll certainly do it to my truck. Thanks,

Raul

Yep, sure does. Works on my 1979 T-Bird, too, but it has a dual-inline-4 (351W) engine instead...

[JackFish]

For an excellent tech thread on this topic go to:
http://www.carbdford.com/viewtopic.php?t=5543

oh, and this one too:
http://www.carbdford.com/viewtopic.php? ... 7c35804eab

[Guest]

Just an FYI - The above mod didn't work for me - it gave me way too much advance at part throttle and also at higher rpms at wot. The part-throttle could be dealt with by an adjustable vacuum advance, but the high rpm/wot could only be dealt with by either putting the "stock" (rebuilt dizzy) springs back in or by backing off the whole timing curve.

My DS1 dizzy (spec'ed from a '75 Maverick), is using the centrifugal advance slot marked 13, which means 26 degrees centrifugal advance (right?). I wouldn't mind shortening the slot to 20 degrees and putting the Mr Gasket springs back in if it didn't mean completely disassembling the dizzy and brazing up the slot.

What I did was put the original heavy/lighter springs back in, and then bend the tab for the heavy spring outward so that the lighter spring lets it advance up to about the 18-20 degree point (measured with my kid's plastic school compass), then it's got to overcome the heavier spring for the last 6-8 degrees. I only had to bend the tab outward 1/8 inch, so I'm not too far off from the curve I had, just restricted the higher-rpm advance a little more.

Initial advance is at 8 degrees (much more and it's on the edge of pinging on a hot day with the a/c on.)

It drives very well, nice throttle response at lower rpm, and it doesn't ping at all, even on hot days (95F).

Here at 6000 feet high, the underhood FoMoCo sticker says 10 degrees static advance. When I installed the new spring, it was 20 degree weather. When it suddenly warmed up to 80 for a couple of days (typical Colorado February), it pinged and knocked, like yours. I backed off to 8 degrees static and the MPG went UP, which surprised me. Then, when the "Springtime" gas came out 2 weeks ago, the MPG went UP again.
Mind you, I have a block heater and keep it plugged in all the time, so the choke is not a factor in my tests. Next will be the "Summertime" gas, in mid-June, and I'll see what happens then. One thing for sure, it will cost more.

I can only surmise that if the fast advance is used, then less static is desirable. I know this is true on my motorcycles. So far, I am +4 MPG in my normal driving for this little investment, even though the static advance is 9 now instead of 10 or 8. This should probably be about 6-7 degrees at lower altitudes, but you'll have to test yours to see how close that is where you live. One advantage of the slower timing: I can idle at 500 RPM in drive (auto) with the A/C on, and it saves gas.

[Guest]

Hi:

Would the modification described by MarkP (Mr. Gasket #925D distributor springs and support arm bending) work on the larger 240-300 ci ford engines?

If it does I'll certainly do it to my truck. Thanks,

Raul

I don't see why it wouldn't.

[Guest]

Just an FYI - The above mod didn't work for me - it gave me way too much advance at part throttle and also at higher rpms at wot. The part-throttle could be dealt with by an adjustable vacuum advance, but the high rpm/wot could only be dealt with by either putting the "stock" (rebuilt dizzy) springs back in or by backing off the whole timing curve.

My DS1 dizzy (spec'ed from a '75 Maverick), is using the centrifugal advance slot marked 13, which means 26 degrees centrifugal advance (right?). I wouldn't mind shortening the slot to 20 degrees and putting the Mr Gasket springs back in if it didn't mean completely disassembling the dizzy and brazing up the slot.

What I did was put the original heavy/lighter springs back in, and then bend the tab for the heavy spring outward so that the lighter spring lets it advance up to about the 18-20 degree point (measured with my kid's plastic school compass), then it's got to overcome the heavier spring for the last 6-8 degrees. I only had to bend the tab outward 1/8 inch, so I'm not too far off from the curve I had, just restricted the higher-rpm advance a little more.

Initial advance is at 8 degrees (much more and it's on the edge of pinging on a hot day with the a/c on.)

It drives very well, nice throttle response at lower rpm, and it doesn't ping at all, even on hot days (95F).

You could also try using manifold vacuum for the distributor instead of spark port, if this spring mod causes low-speed ping. The manifold vacuum drops at the moment you jump into the throttle, then returns when you let up, but the springs advance in the meantime. This was Detroit's fix in the 1981-84 era when short gas supplies caused lowering octanes. It works well on many cars.

[Halebopp]

Does the electronic isgnition then , do away with the vacuum advance as in dual vacuum advance

[fordconvert]

THe term 'electronic ignition' only refers to the way the coil is triggerd. A conventional or 'points' system uses a set of breaker points (which is a basic switch) to directly switch the main coil on and off. A 'breaker less' or 'solid state' or 'electronic' ignition system uses some low voltage usually non contact method to sense the distributor position to trigger a control module or box of some sort that then electronically with some sort of semi conductor turns the coil on and off. Most american cars after 1974(ish) had some form of electronic ignition. GM had the HEI (high energy ignition), Ford had the Duraspark's, and I dont remember what the mopar verson was called. The benifit with the electronics is that they could make a bigger spark without burning up the contacts on the points and since there were no longer any contacts anywhere in the primary system they more or less in theory would last for ever. In the 70's and early 80's they all still had weights and springs to control the mechanical advance and a vacuum modulator. In 81(ish) when most of the cars got computers they began controling the timing with computers and got rid of the weights and vacuum cans. Late 80's things got more complicated and they eventually got rid of the dizzys all together. Some of the MSD type of boxes can be added to older dizzys and control the timing but most of them can not because that falls under the emissions laws so till recently there were not many choices.


The dual advance thing was only for some emissions classes. One was retard and one was advance. I never messed with one but I assume there was some temp or computer controled port that would force it to run or retard a certian way for some situations like maybe warm up. The few people I have talked to that have had them have bought a single advance unit when the upgraded to the DS and have not had any issues.

[Halebopp]

Is this all I need then for Duraspark 2 conversion?

What year and model, 78 Fairmont / Zepher?

Distributor
DSII is it called an ignition, or control module or what.

Can I buy these items new? anything else I would need?

If a were to call a parts store and ask for a DSII and a distributor for a 78 Fairmont, would they know what a DS II is ?

[fordconvert]

Ask for a single advance dizzy for a 78 fairmount with a 200I6 and a duraspark ignition module. The ones with the blue gromits seem to be the standard and common ones, the other colors are for the strange emissions and seem to cost more and be special order.

If you want new neat and clean and have the money I have heard good things about the DUI that you can buy from Classic Inlines. It only needs 1 wire (unless you have a tach then 2) and the module and coil are in/under the cap so its a clean install. Only possible bad things (depending on your point of view and cashflow) are cost and that looks like a GM dizzy. Search around here there are plenty of topics and pictures of the DUI's and also the DS2 stuff.

[Jamie Miles]

Just did this mod to my '72 Maverick (Duraspark II distributor from an '83 Mercury fired by a MSD 6AL box and MSD Blaster TFI coil).

Problem is (if it is a problem), the car will not run with the vaccum advance hooked up anymore. As soon as you try to rev it up with the vaccum advance connected, it coughs out the carb and dies. Without the advance connected, the car runs excellent. It accelerates WAY better then before and screeches the tires going into 2nd gear. I am getting way better gas mileage around town and on the highway. Between about 40 and 70 mph, it accelerates like never before. Since it runs so much better, should I just leave it as is with the vaccum advance disconnected?

[BaldEagleMav]

Hi Jamie,

I would say "Nothing speaks louder than good results!"

If my car were running better without the vacuum advance connected, I would leave it disconnected.

Regards,
BaldEagleMav

[64falcon200]

I am going to try this mod, but I waant to be sure I am replacing the correct spring with the mr. gasket spring. The way I understand it the spring I need to replace is the one made out of the thinner wire... and bend the tab in on the thick spring?

[85BLUEVAN]

I've changed the lighter spring without any problems. I'm not making sense out of the bending 3/32". On the heavier spring, the slotted end is out away from the center of the unit. The non-slotted end is on a very heavy post, just .21" from the shaft. I think any effort to bend that heavy mounting post toward the center would damage it. I obviously am missing something. Please provide some advise or additional information.

Thanks.

[Ronbo]

You can also limit the amount of timing by slipping a piece of vacuum hose over the tab in the timing slot. Thicker hose will amount to less timing. Just pull the factory sleeve off and slip the hose on. Voila!

Ron

[JackFish]

Just did this mod to my '72 Maverick (Duraspark II distributor from an '83 Mercury fired by a MSD 6AL box and MSD Blaster TFI coil).

Problem is (if it is a problem), the car will not run with the vaccum advance hooked up anymore. As soon as you try to rev it up with the vaccum advance connected, it coughs out the carb and dies. Without the advance connected, the car runs excellent. It accelerates WAY better then before and screeches the tires going into 2nd gear. I am getting way better gas mileage around town and on the highway. Between about 40 and 70 mph, it accelerates like never before. Since it runs so much better, should I just leave it as is with the vaccum advance disconnected?

The ds2 dizzy needs spark port vacuum from the carb. It should be connected to a port on the carb that is above the throttle plate.

[JackFish]

I am going to try this mod, but I waant to be sure I am replacing the correct spring with the mr. gasket spring. The way I understand it the spring I need to replace is the one made out of the thinner wire... and bend the tab in on the thick spring?

I disagree with that. It seemed to me upon close inspection that the "heavier" spring is the one with the thicker wire. And that is the one that I replaced with successful results.

I've said it before, and again, I believe the sticky has some confusing info that should be corrected.

[JackFish]

I did not bend any tabs and have had successful results changing the secondary spring out, which is the thicker, heavier spring.
This allows the advance to come in sooner (more quickly) and smoother.

[Patrick66]

I did not bend any tabs and have had successful results changing the secondary spring out, which is the thicker, heavier spring.
This allows the advance to come in sooner (more quickly) and smoother.

this one?

[JackFish]

IIRC, yes.

[xpsnake]

Was there ever bottom line clarification to this mod?

[60s Refugee]

So, I take a rebuilt 1978 DSII from Advance Autoparts and jamb it in the hole, hook up the modules and stuff, and use the factory vac advance using the stock Autolite 1100. I leave the DSII springs and tabs alone. What can I expect?

Harry

[frogmn666]

I want to know this too. That's what I'm in the process of doing. I've curved dizzys before, but there are so many variables, compression, total advance, when it comes in, load, gearing, air temperature, altitude, etc.

If nobody objects to a DSII thread that has already been beat to pulp, I may do one on using a late `70 series Fairmont dizzy with a parts list, pics, and results. I've already seen many descrepencies with this install and there are some critical items and precautions to note.

I am by no way an expert on timing, but I have been working on engines since I could hold a wrench; over 50 years experience and may be able to clear up a few things.

Below is a link to a long and good read that I've read through and totally agree with. Don't let this thread die or get locked as there are new people like myself that need to know the right way to do this. I will add what I can as I progress.

Any of you experts know if there is a difference between 10-13L and 10-15R slots? My 78 DSII has 10R and 15R curves.

http://www.carbdford.com/viewtopic.php?t=5543

[grocery getter]

I used both springs in the 925d kit. I didn't like the ease of advance, so I bent the tabs out.

before this I had a miss at cruise.
now, it's smooth through the power band.

yeah, it's a bit of a monkey wrench in this thread.

bottom line... too many variables in a 40 year old car. you need to play with it.

Mine--->12 degrees static on the 13L arm.
aussie head, 2v carb using port vacuum.

[BIGREDRASA]

I just did new topic, taking off from this one, with emphasis on economy instead of power.