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351w 2bbl to 4bbl & intake swap

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85lebaront2

Re: 351w 2bbl to 4bbl & intake swap

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It was released in 1981 for MG and Jaguar 6 cyl cars, the complete system required a module and distributor replacement as the OPUS system distributor was not able to be converted (FWIW, OPUS stands for Oscillating Pick Up System). The OPUS system used what amounted to a small transformer with three legs, a set of ferrite rods in a plastic ring provided the fourth leg and the A/C voltage of the transformer would spike, triggering the system to fire the coil.

The Constant Energy system uses a magnetic pick up coil that looks like a Chrysler electronic one.

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

Blacktop

Re: 351w 2bbl to 4bbl & intake swap

In reply to this post by 85lebaront2

Interesting, I’ll look in to it and see how much they are and there availability 👍

1984 F150 XLT short bed 4x4 351w 4speed manual
1980 F100 long bed 2wd 300-6 3speed manual project truck
🇬🇧UK based truck enthusiast🇬🇧

LARIAT 85

Re: 351w 2bbl to 4bbl & intake swap

In reply to this post by Blacktop

I *personally* would not wire in an HEI module into a DSII ignition for the reasons Gary mentioned. I don't understand why someone would want to wire in a GM part in a Ford vehicle (or vice-versa) for little to no gain. Using a complete GM-style HEI ignition system for the one wire hookup is one thing, but to replace the DSII ignition module for a HEI ignition module makes no sense at all. Absolutely nothing will be gained using an HEI module over the stock DSII module.

If you keep your vehicle as close to stock as possible, you don't have a have a good memory.

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.

85lebaront2

Re: 351w 2bbl to 4bbl & intake swap

Administrator

You have to remember, he is in the UK and a Lucas packaged HEI module is probably a lot easier to find over there than a DS-II box. I was trying to give him a, hopefully, easier for him option.

If I hadn't been around the Lucas Constant Energy ignition systems from the introduction, I would have no idea what they are.

It is like trying to find parts for older UK imports here in the "colonies".

Bill AKA "LOBO" Profile

Gary Lewis

Re: 351w 2bbl to 4bbl & intake swap

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In reply to this post by LARIAT 85

Rick - You may not have seen Ray/NotEnoughTrucks post in the Lost And Cornfused thread, but Daniel Sterns' article about using the HEI module is very informative. Granted it is a comparison of the HEI to a Chrysler ignition, but I believe the DS-II ignition would have essentially the same waveform as the Chrysler. That's because both use a ballast resistor.

The skinny wiring and ballast resistor that both Ford and Chrysler used severely limited the current to the coil. And the current multiplied by the time it flows determines the energy stored in the coil. Since the energy you get out is the energy that you put in, minus that for heating, the spark cannot be as strong with a current-limited approach.

While I'm not advocating installing an HEI module in place of a DS-II module because of the limited availability of parts when on the road, there is an advantage to doing so - a hotter spark. And if one were to carry a spare of some kind or make the module easily-swapped then I could see doing it.

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

Blacktop

Re: 351w 2bbl to 4bbl & intake swap

In reply to this post by LARIAT 85

I'm not replacing a DSll module for a hei module. I have a tfi system that wont work once I remove the ecm after swapping from 2 barrel feedback carb to 4 barrel Holley.
My choice is wether to retro fit a dsll system or go for the hei system.
Not looking on starting any arguments on this forum, just asking for some info from some knowledgeable people here. I think the lucas system is a none starter as even over here they are very expensive. Cheaper to import the parts from the USA.
If I can source a harness, I think I will go for the dsll set up and import the parts.

Many thanks for all your help guys,
Alan

1984 F150 XLT short bed 4x4 351w 4speed manual
1980 F100 long bed 2wd 300-6 3speed manual project truck
🇬🇧UK based truck enthusiast🇬🇧

Gary Lewis

Re: 351w 2bbl to 4bbl & intake swap

Administrator

I'm not sure they are "arguments", but just debates about the merits. Sort of along the line of what's happening in Parliament at the moment?

Anyway, I kinda thought the Lucas module was expensive. So a DS-II module is probably cheaper. But, there are lessor and greater DS-II modules. Originally they had a timing retard feature in them triggered by power in the Start circuit. This helps the engine crank by slightly delaying the spark and effectively retarding the timing.

But some modules don't have that. When I got Big Blue the engine was struggling to start because it would kick back frequently. I determined that the module that was on it didn't have that feature, so put one on that does, and the engine now starts much easier.

I can't tell you for sure which modules have it, but the consensus has been that most true Motorcraft ones do, as do the NAPA Gold ones. But many of the chain store ones don't.

Gary, AKA "Gary fellow": Profile

Blacktop

Re: 351w 2bbl to 4bbl & intake swap

All good info Gary👍
Thanks.

1984 F150 XLT short bed 4x4 351w 4speed manual
1980 F100 long bed 2wd 300-6 3speed manual project truck
🇬🇧UK based truck enthusiast🇬🇧