Dramatically better MPG with the DurasparkII

  • Thread starter Thread starter Anonymous
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It appears you found 2oz difference, which apparently was quite measureable.

DS II Smaller Spring (Blue) 1/8� pull = 4 oz./ ¼ lb.

925D Spring (Both look the same), 1/8" pull = 6 oz.

And contrary to another member's experience, replacing only the heavier secondary spring was in my case quite good.
 
I had to bend the primary tab, in the original position, it did not provide enough pre-tension IMO, it was loose. I did not have to bend the tab for the secondary spring to be installed. My timing marker won't work, I have to draw a new one, as the 250 CI balancers are 6-7/8" versus the 6-1/8" I made it for. I advanced my initial to what I assume to be about 17 degrees, no pings, I believe it was an improvement. I detailed her this weekend, off subject, to go to the local monthly carshow for the first time, we had fun, need to post some pics.
 
i replaced the wider spring with the mr. gasket spring and bent the tab 3, 3/2's inward on the spring that had the slack to give it more slack, is this the right way to do this? :hmmm:
 
You fellas are shooting in the dark. Yes you can set the initial at 18 but your total will be way over 45 degrees.
Myself & FSD weld or braze the mechanical advance slot as required.
There is more labor involved than you think.
That's why a sun tester is necessary to set the advance curve properly. I can fine tune when the advance starts & when it reaches the proper total. No guess work.
The GM DUI aka HEI has the wrong weights, springs & does not even have a stop for the centrifugal advance total.
They are three times more labor intensive than other distributors.
When properly set up they still require periodic inspection of the advance mechanism because of 50K volts 1/8" above the mechanical advance. Bill
 
my engine is running smoother but i lost alot of vac now im at about 12 on my vac gage in gear at 700rpm, i think ill just have a pro do this the right way, ive invested too much to micky mouse.
 
Sadly, the fact is that the orginal poster "the66mustang", and following on posters and foundational assitants like "Linc's 200”, ” CaedesAd6”, ” MarkP” are all off the memeber list .

As a side note, there was not, nor ever has been, an official Police Interceptor 3.3 I6, as a DSO option or otherwise. I've researched the advent of the proposed 2-bbl log head 3.3 engine which Car Driver listed as an RS Capri option for the 1980 model year, but it never existed as it was never emissions certified, and FoMoCo never made the combo legal. That is certain, as there is no listed engine code for it, nor an EO number, or 2-bbl carb detail. Listed 2-bbl XE code engines do not count, as the only sold off 2-bbl XE FoMoCo head was a 1977 casting modeled off the earlier 3.3 Fairmont package, and it did not have the large diameter exhast header.

As such, the validity of Mark P's statements on ignition are partly undermined. He had some very important info that only an Ex Ford engineer could have made. As it stands, you can't search the masses of igntion info "the66mustang" and ” MarkP” made before falling off the radar after a board crash.

The info is valid on the Duraspark II, but unless you compare the actual advance with the needs of your engine in terms of base at idle advance, and peak advance and where it needs to come in for your cam, compression and carburation, your shottin the breaze. A formulaic approach is not likely to yield the results you expect. Dyno and Sun machine recurve, with final chec with a dial back timing light, are the only best ways to get the performance and economy improvement you need.
 
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