1982 Mercury Grand Marquis

[mgm82]

Hello to everyone! I am getting ready to buy a 1982 Mercury Grand Marquis 5.0L with carb and I would greatly appreciate some help. I am generally aware that the car has a computer (EEC) that controls basic engine functions. It is my understanding that the EEC receives input from things like a crankshaft position sensor, O2 sensor, throttle position sensor, etc. It then uses all of the collected data to adjust things like air/fuel mixture, timing, etc.

1) Can the control of these basic engine functions be removed from the computer (EEC) and returned to the driver? That is to say, can the variable venturi (vv) carb be replaced with one that is manually adjusted? Also, can the distributor be replaced with one that is manually rotated to adjust engine timing? I would love to take the computer completely out of the loop.

2) Since the car is now 26 years old, would performing #1 create any problems with yearly safety or emission inspections? I heard something about the Federal Clean Air Act of 1990 but I didn't understand it. Does a car this old actually have emission standards and requirements?

Can someone please help?
Thank you!

[gadget73]

see reply in your other post

[88Vic]

I'll let someone more informed then myself help you out, but to GMN mang.

[Marauder_63]

'82 Carb & Dizzy Swap

Hello mgm82 -

You're a guy after my own heart (so to speak). I tackled the exact same swap on my '81 GM w/302 & started out with the very same (good) questions. After a bunch of research & thought & trying to figure-out what to keep & what I to toss; what'd keep the computer happy & what'd keep me happy, I ended up changing my whole approach to the project. I decided to try & do everything I could (without cracking open the motor) to set the "time machine" back to pre-emissions days when a SBF looked & ran like a SBF.

Towards that end, I first carefully removed the VV "carb" from the manifold, then just as carefully placed it on the ground & drove over it with my '69 F-250. That being accomplished, I felt that I was truly on the right track from that point on. As a replacement for the dearly-departed VV, I scrounged a Motorcraft 2150 & did a thorough rebuild & re-calibration on it. The original application on this carb was '78 Ford TRUCK - 351/400. The 2150 out of a truck (including the 360/390) actually make a really decent starting point for this application. They generally came with larger throttle bores/venturi clusters, as well as larger jets. This gives you an advantage right out of the gate over the "leaned for emissions & fuel mileage standards" calibrations found on passenger cars of that era, i.e. resticted air-flow through smaller bores & venturies with even more restrictive fuel-delivery through smaller jets.

The 2150 lends itself especially well to tuning for the low-compression 302's of the late '70's-early '80's like ours, largely because its based on the earlier Autolite 2100. Those vintage Autolites are simply kick-ass on SBF's & their bigger brother, the Autolite 4100-4V, is considered to be pretty much the ultimate in Ford OEM retro-carbs. Besides the
simple & bullet-proof 2-piece design, their major performance claim-to-fame is the Annular Fuel Discharge feature of the venturi boosters. The term is seen spelled with capitol letters for a reason: it was a Ford-owned & patented engineering development dating from the late '50's; which was so highly thought of by Holley that for years they paid Ford for the rights to use the system on their carbs & eventually bought the license outright after Ford went exclusively to F.I. on all of their vehicles.

Basically, the crucial difference is the presence of several small holes in the upper part of the venturi booster through which the fuel is delivered in a more evenly & thoroughly dispersed manner than with the more conventional downleg & straightleg boosters. The result is improved atomization of the fuel/air mixture over a longer period of time. That in turn allows an increase in the volume of air-flow & fuel delivery to be introduced, the basic ingredients of horsepower. This demand for fuel and air is met by the larger throttle-bores, venturi clusters & jets used with annular setup. These, in concert with the more precise & adjustable fuel METERING which is also a feature of these carbs, make available a wide range of calibrations for practical use in a myriad of applications. Best of all, when all this engineering is brought to bear on the small block, through its separate bores, dual-plane intake, the real-world, behind-the-wheel pay-off comes in the form of that grin-producing right-there, right-now throttle response & boot-in-the-butt, low-end pull that just makes it all worthwhile.
There are a number of additional specific tuning details concerning jet size, air diverters, pump shots & the like, as well as some useful pics & killer links that I've managed to put together & would be more than happy to share 'em forum-wide or respond to individual personal messages. And hey mgm82, if you want we can get into the actual step-by -step mechanics of the conversion process, as well.

Re the ignition: same approach here as with the fuel system. Best bet is to score a Ford OEM DuraSpark II disto; the earlier the application the better & again, bigger is generally also better, so units from FE's and/or trucks are ripe for consideration. Ideally, late '60's, high-perf units are the ones to have. They come setup with (or have a provision for) a quicker & increased total timing-curve, & when married to an adjustable vacuum advance cannister and performance-calibrated centrifugal advance springs & weights, the tuneability to specific apps is nearly as numbered as the carb setups that I talked about earlier. Ditto the sharpened throttle response & stout low-end.
As for EMU's, just match-up your DuraSpark disto with a DS control module (blue grommet is better than yellow; both will work) & you've got the best of all worlds: a breakerless, high-output ignition, with tuneable vacuum & total-advance timing curves; all wrapped-up in a time-tested & proven, reliable-as-a-stone package.

There are three basic routes to go with when procuring a DuraSpark setup: third party performance manufacturers like MSD, Accel & lots of others build components & full systems based on Ford's design. These outfits are fairly expensive but furnish high performance & reliability. For my personal taste though, especially in the context of an affordable, daily-driver, they just strike me as a bit of pricey overkill.

The next alternative is to go with new or refurbed Ford OEM components. These are significantly cheaper, readily available from either the usual parts houses or the Ford dealership. If a person does some research & comes up with a set of components that will work together & match the application, its possible to put together a system for half to two-thirds the price of the big-name, big-performance outfits. And more importantly, these proven, widely-used DuraSpark components provide performance & reliability nearly equal to that of the high-perf aftermarket pieces.

Finally, its is still quite feasible to find & purchase all the individual components, or even intact & complete DuraSpark systems from wrecking yards, swap meets, or auction sites like eBay & others. It can be a challenge pulling together a system that's right for your application, while making sure that the parts are servicable or rebuildable or even the same as advertised. Gotta have a fair dose of patience, a good dickerin' demeanor, and a working knowledge of the Ford's cryptic parts numbering system & parts interchangability really helps. Either that or a good parts interchange book to refer to. And also what I said about having gathered a pretty useful bag of tricks, pics, & links re the carb conversion goes for the ignition as well.

Just all depends on your dollar budget, time budget, fuss budget, and overall personal preferences. For me, I still take some morbid pride & satisfaction in putting together a sharp running, sanitary looking install made from all retro-Ford OEM stuff with modern improved fasteners, connectors, wiring, etc. "Improving the Breed", isn't that how it goes?

Anyway, I'd better go to work sometime this week. I'll try to lay out how I dealt with the emissions gear & computer a little later. Hope this helps some. Its kind of a long-wind bunch of theory & history, but if a person uses that to determine which components, with what features, will provide a good solution to their application, the rest - from scoring the parts &
buffing 'em up, to doing the actual install - is fairly fun & straight forward.

S#*t, I'm late!

[mgm82]

Marauder 63:

Thank you very much for this information. I'm so glad that someone here understands what I'm trying to do, which is:

1) bypass the computer (EEC) as much as possible and retake control of things like air/fuel mixture, timing, etc.

2) clean up the engine compartment by removing as much of the emissions gear as possible.

I would greatly appreciate any additional information, especially on emissions gear and computer, that you could provide. Thanks again and I look forward to your next post.

mgm82