Distributor Curving, TFI Coils, Life, the Universe and......

[I66coupe]

Everything!

What determines what the curve should be in the distributor? How do I determine what the curve should do? There's a thread here about curving and its suggested to send the distributor to a fellow and let him do it for you. How is it determined what the curve should be? How can he decide how to adjust or modify the unit to suit your particular engine? Are there some basic guidelines we could use?

I am planning to install a 1980 DuraSpark in my '66 engine. I would believe that the curve will need adjustment due to the differences between a smogged 1980 engine in a Granada and my non-smogged 1966 Mustang engine. How do I decide what it should do? How far should it go? How fast should it get there?

I read here that the 1100 spark control will pull the advance too far and pinging is likely. So, what is the problem with the vacuum signal from the 1100? Is it that the vacuum is too strong too soon? Does it slam the advance full on way too soon? Effectively bypassing the weights? They essentially do nothing due to the strong vacuum signal slamming the advance full on? Is it that the SCV applies too much vacuum at higher rpms and thus advances the timing too much? If that is so, can't I simply limit the advance travel with a screw installed in the distributor to interfere with the advanve arm's travel? I gather that I will need to replace the 1100 with something else because of this problem. Thats ok, I have a 2100 on the shelf. Couldn't the SCV problem be addressed by using a later carb? Is that what I should do? Replace my '66 1100 with a '68 or later 1100?

I read that I can open up the gap on my plugs to take advantage of the higher energy spark. I uderstand that. I upgraded the ignition on my '83 Jeep J20 by using the Ford TFI system. The Jeep engines came equipped with the DuraSpark ignition but used the old, lower powered canister style coil. I opened up the plug gap to the amount suggested by the Jeep crowd and the upgrade worked wonders for the old Jeep. How do I determine how far the open the gap for my '66 200? How do I decide when I have opened them up too far? Not far enough? What clues do I look for to tell me this?

In the DuraSpark conversion for the '66 engine, its mentioned that it will supply more energy. How? Is the DuraSpark coil more powerful? How does its output compare to the TFI coil? After seeing what the TFI coil did for my Jeep 360. I would think using the potent TFI coil with the 200 would also be a great idea. But, I only see the canister style coil mentioned for use with the DuraSpark conversion on the 200. In the TFI conversion for the Jeep engines, its mentioned that the TFI coil has faster rise and fall times for more precise timing. Wouldn't this benefit our engines as well? This is pointed to as a big plus for the TFI coil over the canister style.

Also, in the article about the DuraSpark conversion, its mentioned that the white wire retards the timing for less load on the starter. The Jeep system uses this feature and it works great. But the article points out that the Mustang wiring can't accomplish this with its stock wiring configuration. Well, just use a relay controlled by the start terminal. When the start terminal is energized, the relay will pull in and supply power to the white wire independant of the stock wiring system. When the start terminal goes dead when the key is released, the relay drops out and power is cut to the retard wire to the DuraSpark module. This is not mentioned in the article.

I have questions, do you have answers?

 

[Lazy JW]

Good questions, well thought out. You are very close to enlightenment

#1) I am very reluctant to let some all-knowing guru re-curve my distributor when he has never even seen my engine, much less driven it. He will just make a ballpark guesstimate, do an average re-curve job, it will run better than stock, and you will be delighted because it runs better. BUT, you can do the same yourself if you are careful, and maybe even better. That's half the fun of hotrodding anyway, doing it yourself rather than just writing a big check and buying a turn-key setup. Go buy a Chebbie if that's what you want (JMHO)

#2) This is a pretty big topic in itself. You need to map the existing curve first. Mark the timing pulley up to at least 40 degrees. Using a timing light, rev up the engine and note how much it advances at what speed. Road test for best power at upper rpm, adjusting timing until it pulls best, then back off at least one degree for safety margin. Adjust static timing for best vacuum at idle, then back off one degree. The difference between the best idle setting and the best power setting is how much advance you need. Now adjust the mechanism to allow that much advance, play with the weights until it gives a linear curve all the way up. It should be all done advancing around 3000 rpm. This is probably over-simplified but I hope it helps.

#3) I am not familiar enogh with the 1100 to be any help

#4)Open the plugs up .005" at a time. Road test by lugging it HARD in high gear with a heavy load up a hill at full throttle. When you have opened them too much it will let you know.

#5) Contrary to popular belief, the Duraspark coil isn't much of an improvement over the stock breaker point coil. It still uses a ballast resistor so the primary current is about the same. The laws of physics don't allow us to get something for nothing. Most of the improvement from the DS2 is getting rid of the points, the rest is mostly the placebo affect (that statement should bring some hate mail). The TFI coil is INDEED a better coil with higher inductance. I recently did the TFI/HEI/ DS2 coversion on my truck. I like it 8)

#6) If you use the starter relay that has a terminal for "Ignition" you could hook the white wire there and get the retard function for starting.

Joe

 

[I66coupe]

Thanks Joe. I mentioned the relay attached to the starter terminal for spark retard because the article says the starter ran on after the engine started when he connected to it. I see now that I misread the passage and it turns out he had connected to a wire under the dash not the starter terminal and he suggests trying the starter terminal instead. My bad.

I am certainly going to use the TFI coil as I have one here from the Jeep conversion I did a few years ago. I bought the coil from a junkyard but went with a new MSD BlasterII version for the truck and stuck this used Ford unit on a shelf. See, being a packrat pays off now and then.

I just need to figure out this vacumm problem from the 1100. I have discovered that the 1968 and later 1100s have a smaller venturi than the older carbs. Not good. The SCV is gone but the venturi is smaller. I guess I may go that route for the time being and do something more about the carb situation later. What I thought was a Motorcraft 2100 on the shelf in the garage turned out to be a Holley 2300 instead. Still a good carb but I'd rather use a 2100. Time for another junkyard crawl. Oh no!

 

[wsa111]

For you fellows using pre 68 1100 carbs just block off the scv & use manifold vacuum to the duraspark or your 68 up distributor.
the engine will run to perfection, especially if you have a more than stock camshaft.
If you have problems with the stock camshaft at idle you may have to install a vacuum advance with less degrees advance.
Remember pony carburetors has a 215 CFM 1100 carb which uses the 223 big six venturi to achieve the larger CFM air flow. William

 

[Stubby]

I66coupe
42 is the answer, just not the amount of advance 8)

 

[I66coupe]

But to understand the answer, you have to know what the question really was.