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DS I vs DS II conversion

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Danny G

DS I vs DS II conversion

OK so the long term plan has been to convert from feed back/computer to Duraspark II.

This comment was made on someone elses thread on the FTE boards:
"you could go to a DS I system and get the benefits HEI and no ballast resistor. Plus you can retain and take full advantage of the TFI coil. "

What do they mean by taking full advantage of the TFI Coil, is a DS I conversion really easier/better than doing the DS II swap with GM HEI module?

Is there any inherent benefits to one over the other? I have an 86 and also read rumor that the DSII provisions may already be present.

1986 F-150|Standard Cab|4x2|300Six|C6Transmission w/3.08 rear|Name:TBD
2021 Ranger XLT Super Crew

ArdWrknTrk

Re: DS I vs DS II conversion

Administrator

The connectors and resistor wire are already present in the trucks harness.

To convert to DSII you need: the module, distributor, coil, and the harness that connects the three.

The efi coil doesn't work as well as the dedicated DSII coil because of resistance vs the load switching transistor in the module.
~
I also expect without the resistor in the DSII harness, the *older can type* coils become saturated and heat up.
(I don't think dwell is limited in the DSII system)

Bill Vose should have all the details, but that is my shade tree interpretation of my own observations.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ArdWrknTrk

Re: DS I vs DS II conversion

Administrator

In reply to this post by Danny G

I think the main benefit is they are not only rugged, reliable and stone simple, but that parts are on the shelves of almost every parts store in the nation.

Though, this is beginning to change.
As new chain stores pop up, they never bring in that inventory, because it's so out of date.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

85lebaront2

Re: DS I vs DS II conversion

Administrator

I will get back to you on this thread later, I have to take advantage of a reasonably warm day and get some things done.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

Gary Lewis

Re: DS I vs DS II conversion

Administrator

85lebaront2 wrote

I have to take advantage of a reasonably warm day and get some things done.

Good idea, Bill. It was 46 when I got up at 5:30 this morn, but it is 33 now and headed to 15 tonight. And it sleeted a bit ago so my trailer is covered. I sent the weather your way.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

LARIAT 85

Re: DS I vs DS II conversion

In reply to this post by Danny G

TheScatch wrote

OK so the long term plan has been to convert from feed back/computer to Duraspark II.

This comment was made on someone elses thread on the FTE boards:
"you could go to a DS I system and get the benefits HEI and no ballast resistor. Plus you can retain and take full advantage of the TFI coil. "

What do they mean by taking full advantage of the TFI Coil, is a DS I conversion really easier/better than doing the DS II swap with GM HEI module?

Is there any inherent benefits to one over the other? I have an 86 and also read rumor that the DSII provisions may already be present.

DuraSpark I and DuraSpark II were both released in 1977. DuraSpark I was only used on vehicles sold in California, where emissions standards were tighter. The other 49 states used DuraSpark II.

DSI is supposedly "better." But I don't think you would notice the difference between it and DSII. The DSI ignition modules are about twice the cost of a comparable DSII module. Reliability was so bad with the DSI modules, that Ford mechanics apparently referred to it as "NeverSpark."

DuraSpark I was replaced with DuraSpark III in 1980 for California vehicles. Since it was only used for a few years and only in California, you are *not* likely to find a replacement DSI module in stock should you need one.

Duraspark II proved to be much more reliable, which is why it was used right up until 1991. Therefore, replacement parts are much more plentiful and more likely to be in stock.

There would be no advantage (and no reason) to use a GM HEI module in place of a Motorcraft DuraSpark module.

Lucille: 1985 Ford F150 XLT Lariat

*Colors: Dark Canyon Red exterior, Canyon Red interior
*Engine: 5.0, CompCams 31-230-3, "Thumper" E7 heads, Edelbrock Performer intake, Autolite 4100 carburetor, DuraSpark II ignition, Thorley Tri-Y headers, Flowmaster dual exhaust, H-pipe.
*Drivetrain: AOD transmission, 3.55 gears, 2wd.

Danny G

Re: DS I vs DS II conversion

In reply to this post by ArdWrknTrk

ArdWrknTrk wrote

The connectors and resistor wire are already present in the trucks harness.

To convert to DSII you need: the module, distributor, coil, and the harness that connects the three.

The efi coil doesn't work as well as the dedicated DSII coil because of resistance vs the load switching transistor in the module.
~
I also expect without the resistor in the DSII harness, the *older can type* coils become saturated and heat up.
(I don't think dwell is limited in the DSII system)

Bill Vose should have all the details, but that is my shade tree interpretation of my own observations.

It seems like a straight forward, almost plug and play swap. I remember reading some where (ill check when I'm ready) about a company that has distributors ready to go. Looks like the harness is available as NOS or as aftermarket from painless, coil and the GM HEI.

1986 F-150|Standard Cab|4x2|300Six|C6Transmission w/3.08 rear|Name:TBD
2021 Ranger XLT Super Crew

ArdWrknTrk

Re: DS I vs DS II conversion

Administrator

The distributor socket is the only one not easily available.
And that one can be rigged by using a four pin socket from the Motorcraft pigtail catalog and removing one pin and a clocking fin sticking inside the socket.

In one of my posts I compared the $ Painless harness to readily available parts..... Just like I did with the 3G conversion parts...
It irks me when a "kit" costs more than double what all the bits do.

But then, I like rooting around for stuff and tinkering with it.

I haven't seen a NOS DSII harness, but IDK the part number either.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

85lebaront2

Re: DS I vs DS II conversion

Administrator

In reply to this post by Danny G

Ford built the 1985 and 1986 front chassis harness to be able to accommodate several systems, the plain DSII system, a feedback carburetor system or EFI on the 5.0L engines if you look at the left side wiring harness you will see several plugs, some of which seem to make no sense. The DSI and DSII systems along with the computer controlled DSIII require a ballast resistor in the coil feed. This is bypassed during cranking for a stronger spark with the resulting lower system voltage. Ford started some time in the 60s doing away with the resistor block next to the coil and replaced it with a resistance wire, older vehicles had it as a plug in piece in the dash harness. The extra small terminal on the starter relay, the one with a I is the resistor bypass wire on these.

On the 1985/86 trucks, if you examine the ignition circuits you will see a resistance wire between terminals 11 and 12 of the ignition switch. Terminal 11 is hot in run, terminal 12 is hot in start. When the engine is cranked the R/LG ignition feed is powered through the resistance wire from the BR/PK wire from terminal 12 of the ignition switch, this powers the + side of the coil though connector C325 and through the resistance wire the W/LB wire to the R DSII wire. The diagram shows 3 wires to connector C321 (3 pin) on the DSII module, I believe that only 2 are used if I remember correctly, the R/LB to the W and the W/LB to the R, I do not remember a R/LB to a R/LB as it shows. Once the engine starts, and the key is released the coil is still fed by a R/LG wire, but through the resistance wire, the DSII is now receiving full 12V from the W/LB wire to the R wire. C323 on the DSII is the distributor pickup, system ground and ignition coil -.

On the EEC engines, the W/LB and the R/LG wire are connected together in the EEC harness which plugs into C321 and C325, this way the TFI ignition always gets full battery voltage as the resistor is simply bypassed during cranking and running.

In order to install a DSII on your truck, you need a DSII module and the distributor and the wiring from the distributor to the DSII module. If you insist on listening to the HEI crowd, to make it really work properly it needs a #10 wire that can be fed from the battery with a relay as the HEI is a current hog. This can be done using the wiring from the EEC/TFI feed that tie the W/LB and R/LG wires together and use them to turn on the relay, and if you are so inclined, use a late model oil pressure indicator switch (closed with pressure) to ground the relay, that way if you lose oil pressure, either from a failure or engine stall, the ignition feed to the HEI is cut off.

Bill AKA "LOBO" Profile

ArdWrknTrk

Re: DS I vs DS II conversion

Administrator

^^^^What he said

Gary, this needs to be the DSII tutorial.
Bill is thorough and concise in his description of the components and function of the system that powered hundreds of millions of Ford vehicles between the mid 1970's to 1990

Bravo Bill!

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: DS I vs DS II conversion

Administrator

Bill/Jim - We may have the right place for it. Please take a look at Documentation/Electrical/Ignition and go to the Ignition Simplification tab. There we have an explanation up top and then two more tabs: DS-II and One Wire.

But Bill's explanation doesn't quite fit neatly into the DS-II tab. Instead, I suggest we put the first three paragraphs of Bill's post up top, before the DS-II and One Wire tabs. And then the last paragraph would get split between the two tabs.

I think on the DS-II tab we'd need to include the appropriate schematics from the EVTM, which is easily done. And on the One Wire tab Bill's explanation about where to get the switching signal for the relay fits perfectly with the diagram.

Thoughts?

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: DS I vs DS II conversion

Administrator

It's your baby Gary.
I defer to your knowledge and familiarity with the back end of the forum

I think we also need a schematic for the HEI.
Maybe something like this: XXX

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: DS I vs DS II conversion

Administrator

Bill - Your thoughts, please. They are your words.

Jim - Why isn't this schematic from the One Wire tab enough?

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: DS I vs DS II conversion

Administrator

Because frankly, though I had seen your diagram, I hadn't looked at that tab to realize it was already there!

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: DS I vs DS II conversion

Administrator

No prob. I thought you were saying something more was needed.

Anyway, let's see what Bill says. If he agrees then I'll do some work in a day or two on using his words to explain how the wiring works on these trucks and what is needed to convert to DS-II.

Gary, AKA "Gary fellow": Profile

85lebaront2

Re: DS I vs DS II conversion

Administrator

Gary, it needs to emulate the EEC feed, W/lb and R/LG wires both need to be connected to the relay. The diagram as you have it may "drop out" the relay when cranking. The ignition wiring on these was a solution to providing a solid battery voltage feed under cranking and running for the EEC, or to provide a coil resistor for the DSII system.

Bill AKA "LOBO" Profile

Gary Lewis

Re: DS I vs DS II conversion

Administrator

Bill - Excellent catch! The way I show it the engine won't fire until you turn the key to Run.

I'll fix that and work on that tab later. Thanks.

Gary, AKA "Gary fellow": Profile

Danny G

Re: DS I vs DS II conversion

In reply to this post by 85lebaront2

Gentlemen you are a wealth of knowledge and I am glad this discussion is leading to some documented guides that I and others will have all they need to do this swap to DSII.

The gentleman on FTE had these final 3 tidbits to say. What are your thoughts Bill?

"DS I is a true HEI system that adjusts dwell with engine RPM (DS II is fixed) utilizes a crank retard (DS II does not) and feeds a full 12 V to the coil as opposed to the resisted down voltage of DS II. DS II is not true HEI System like GM's HEI system whereas DS I is."

"The install for DS I is very simple two wires need to be switched around and the centre tab on the male dist connector trimmed of connector (it is clocked differently than DS II but is clocked the same as the crank retard module."

"you can use the TFI coil with DS II with no issues. The TFI coil is designed to run at much higher power levels than what DS II can generate and the Ford TFI coil falls within the operational tolerances of modern (1980 and up) DS II boxes."

1986 F-150|Standard Cab|4x2|300Six|C6Transmission w/3.08 rear|Name:TBD
2021 Ranger XLT Super Crew

ArdWrknTrk

Re: DS I vs DS II conversion

Administrator

I'm not Bill, but DSII definitely DOES use crank retard (iirc 3°)
What purpose does the white lead of the module serve???

The high winding ratio and resistance of the DSII coil will be saturated and become a filament without the resistor.
If the coil reaches full potential, who cares if it is limited by the charging window or a resistor?

45kV is 45kV.
There's nothing 'higher powered' about the TFI coil.
There is a difference in the load that needs to be switched.

As for DS-I, it was needed for Cali emissions, not performance.
And it was discontinued because of unreliability

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ArdWrknTrk

Re: DS I vs DS II conversion

Administrator

Don't believe me...
Ask Bill (Numberdummy) over on FTE.
He was a California parts counter man for 38 years, during the heyday of the Bullnose.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

123