Dramatically better MPG with the DurasparkII

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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).
 
the66mustang":elim94a2 said:
inside the dura ll

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


pict2201.jpg

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...
 
superbepro":95im0wwc said:
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... :wink:
 
jamyers":2r95y546 said:
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. :shock: Then, when the "Springtime" gas came out 2 weeks ago, the MPG went UP again. :shock:
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.
 
superbepro":3oir70pa said:
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.
 
jamyers":29kbbon2 said:
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.
 
Does the electronic isgnition then , do away with the vacuum advance as in dual vacuum advance
 
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.
 
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 ?
 
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.
 
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?
 
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
 
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'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.
 
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
 
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