79 Fairmont De-Smog & Tune Q's (Long)

[Anonymous]

(Wifes' name for car: 1979 Fairmont Ghia Coupe 200-6, C-4, P/S, PDB, A/T, A/C. 62k original)

Bought this car about a year and a half ago from family of original owner. Very nice condition.

Have been reading through the site here, bookmarking, and making a few plans.

Commenced de-smog ops a few days ago; Thermactor and other controls have fallen off. EGR, PCV, thermostatic air control remain. (EGR now run off of Holley 1946 stock ported vent, but through a two-port PVS switch.) Cat convertor soon to fall off.

Cranking compression shows 180-190 in all cylinders.

Dura-Spark II tests out correctly.

Now, to tuning. Car was passing smog check with aplomb, but wanted to remove all "unnecessary" equipment for reliability/simplicity plus trying for a little more pep and fuel economy.

Timing was 6-degrees BTDC (w/o vac advance hooked up); now at 14-degrees. Missing acceleration now found. Vac advance is hooked up to manifold vacuum, and carb fuel/air adjusted to best reading (20 in/hg)
at 500 rpm in Drive. (Richer'n stink at idle).

Questions:

1. Is manifold vacuum the correct way to run this carb?

(Cannot detect any spark knock with or without advance hooked up, even though initial is 20+ at idle.)

(MOTOR Manual shows a fairly mild stock curve. Will be installing CRANE Advance kit (springs and vac canister).

2. Any particular curve recommended? [This is an A/C car in hotter'n hell Texas].

3. Am looking to change to 5200-series carb, do any of them come equipped with EGR and PCV hookups, or will I have to modify carb and/or Clifford baseplate?

4. Am also looking to keep stock air cleaner/thermostatic system in place; any recommendations?

Thanks for any help. This is a great site, and this Mopar guy has learned quite a lot so far.

 

[CZLN6]

Howdy 79daisy:

It sounds like a nice car.

This engine and carb are designed for ported vacuum. If I were you I'd try ported and see if you like/dislike the difference. You can always go back. the reason for the ported vacuum advance is two fold. 1st to give a cleaner, cooler idle, and 2nd to increase mileage at cruise speeds. The ported signal will give little or no vacuum advance at idle, but give a prescribed vacuum advance at cruise speeds. The manifold signal will be just the opposite. High vacuum at idle and not quite so high at cruise.

Given you Texas locale, you will not want anymore initial advance then is really useful. If it doesn't really increase performance, it will still increase temperature. For example if you get the same performance with 10 degrees initial as you do with 14 degrees, the difference of 4 degrees will only generate increase combustion chamber heat. Not what your AC wants on a toasty Texas traffic day.

I'd suggest you do a timed test, with a stop watch and your speedometer. Time it from 20 to 50 mph in 2nd gear, make one change and assess the difference. Also watch your engine heat for differences.

The distributor kit install is not an easy one and unless you have a Sun distributor machine can be a shot in the dark. I'd suggest you stick with your stock centrifugal curve. You may have an adjustible cannister. Many DSIIs did. Take a look at the size of the Allen wrench in a Crane kit at the Parts store and try inserting a similar size in your unit to adjust. Righty tighty slows and delays vacuum advance, lefty loosey has more advance sooner. If you do the kit, you will want to adjust for more initial, less vacuum, and quicker centrifugal for a total of 38 to 38 degrees by 3,000 rpm with an auto trans.

A Holley/Weber from an early Aerostar Van with a V6 had both EGR and PCV, although the EGR may have been in the adapter between the carb and the manifold.

By all means, keep your thermostatically controlled air cleaner system. It's slicker than a mule with the Texas mange. If you must do something, rustle up a K&N filter and have the top chrome plated. This air cleaner system is truly on of Fords better ideas. Cool air when it's hot and hot air when it's cool.

I hope you know that all the good Fox bodied Mustang will adapt to your Ghia.

Enjoy.

Adios, David

 

[Anonymous]

79Daisy,

What is the hot air intake hose for the air cleaner attached to? Is there some kind of shroud around the exhaust manifold? I can never find one of these with all the parts still there. I am using the Fairmont air cleaner now and would like to hook up the thermostatic air intake system, but I can't devise a way to attach the hose.

 

[Anonymous]

In regards the ignition curve, I've got total coming in very fast right now with two light springs; throttle response is up and it takes very little throttle movement to accelerate or engage part-throttle kickdown (something I love on my old Chrysler as well). Will likely put a heavy spring back in after 5200 in place and weather gets hotter. A/C repair will necessitate yet another tuning.

Backed initial off to 10 BTDC (no vac), but am running man vac for the time being. Glad to know that in 1979 that Fairmonts ran ported advance. I've never been a believer in man vac, but a few posts on old threads got me to thinking this may have been common for this motor.

Can't/won't do much with this 1946 carb (CO fumes at idle are a killer without air pump hooked up; headache three days and running), but cat convertor will be coming off in next few days at which time I'll cut and crimp the aspirator tube. Then some final tuning until new carb in place: ported vac, timed run or two as suggested.

(I've had fun calling this car "The Duck" for the sound that aspirator makes under acceleration. My wife won't drive it until I get it "off of MY [her]car". . she sure doesn't like that sound!!!).

Looking forward to the Stovebolt 5200, and, unless anyone can offer other advice, I'll just mod the baseplate and adapator for EGR and PCV.

Thermostatic air control set-up is really outstanding on this car: short runs & under-bumper cold air entry!

Still have some non-engine-related work to finish over next few days so will report back after some more distributor tuning/carb fiddling for best temporary tune, and as to best location for operating flapper valve (like a dummy I forgot to note it as I started to take things apart). Maybe someone else knows.

Thanks, keep it coming.

*edit*
David, your posts are among the best that I've bookmarked; and your thoughts are as mine. I wanted to make sure of what I was up to with this car, thanks for your advice.

(And, yes, the Fox Mustang parts are tempting, but another car project and potential new business has squelched that for now. We'll see what wifey wants after a little more is done. Have a hunch that some improved handling and brakes will be her thing after motor has been breathed on a little. The little 200 has more pep than my high school Maverick did!)

*edit*
Falcon64, I misread your post. Yes, there is a very nicely done shroud and pickup tube for the hot air portion of the Thermostatic Air control. Mine has just enough rust on it that I did not remove it to serivce exhaust heat riser valve (which seems to be working fine, thank you unleaded gas).

As above, the packaging on this system is about the best I've ever seen, 6 or 8, any manufacturer.

The shroud encapsulates practically the whole of the exhaust manifold upper (only the ends are visible), and the lines for the Thermactor system, the EGR system, the Heat Riser Valve, are a part of this shroud(pressure lines are threaded fittings: one for the first, and two for the second system, respectively); the pickup tube for the Thermostatic Air Control arises from the area beneath the above systems.

Well worth searching out, IMO, as EGR/PCV/Thermo Air are proven longevity/driveability enhancements.

This is why I'm hoping to find a FORD air cleaner base that is easily modified to fit a 5200. (Yeah, okay, Pinto . . the ones I've seen are kind of ugly. Was hoping someone knew if a V8 piece
or other would work).

 

[Anonymous]

79Daisy;

I also have a '79 Fairmont. When I had the fumes you describe with the carb, it turned out to be poor vacuum in the passage of the 1946 that pulls the power valve shut. The top plate was warped just a little, so rebuilding it only helped for a few months and the trouble would return. (The power valve was always open a little, so it leaked gas into the manifold all the time).

Long story shortened, it turned out that the little coil of tubing inside the exhaust manifold that delivers warmed air into the carb's choke housing had burned away. It was sending exhaust gases into the choke, then down the throat of the carb, which would overheat the carb and boil the fuel, eventually warping the top plate of the 1946.

I finally replaced the carb ($95) with a Holley rebuilt and made up a choke warmer by wrapping several turns of soft aluminum tubing around the exhaust manifold. The cool air is taken from the horn of the carb on the passenger side (there's a little tube sticking out there) with rubber hose, then it enters the "heater" and then goes to the choke housing. This stopped that noxious fuming and carb boiling it would always do on warm days.

 

[Anonymous]

79Daisy,

Try looking for a Fairmont equipped with a 4 cylinder. They used the 5200 and had the air cleaner w/Thermostatic Air Control). In fact, it looks almost exactly like the one you have now. The only problem might be clearance of the valve cover (because these air cleaners were low profile with "humps" in certain places to clear certain things). But, you could make a spacer to raise the carb. a little or "massage" the air cleaner to fit if necessary.

 

[Anonymous]

Thanks for the responses!

Have gone back to ported vacuum, and seem to have idle & advance fairly well set for now.

I really appreciate knowing to look for 4-cylinder Fairmonts and the tips on the 1946!

*edit*
MarkP, thanks for the tip on the potentially bad power valve/warped airhorn. As I went remove the 1946, sure enough the hot air was rusted completely through at the manifold end. OEM insulation had it covered up.

This little car has more scoot to it than I would have guessed. I always liked 6's, but a smogged late 70's Ford gave me some low expectations.

They've been exceeded and then some.

 

[Anonymous]

Well, been to the one junkyard in DFW I know to have older cars (Little Johns in NE Fort Worth);
found a Pinto 5200 air cleaner for the carb I ordered from Tom Langdon at Stovebolt.

Saw a few clutch fan set-ups on LTDs that I'll go back for as I need some pieces for the Chrysler as well.

Hoping that the air cleaner housing won't present clearance problems, will know in a few days.

Had brakes and u-joints redone by a great old mechanic; master cylinder was also shot.

Am replacing/adding power steering fluid to get a complete flush on the rack and pinion and to try to eliminate "morning sickness"; so far, so good.

In ten days ought to have carb and ignition dialed-in once convertor falls off, really looking forward to it.

Going to keep looking for 4-cyl Fairmont housing, or take these two over to a master metal bender I know to come up with something more respectable-looking and longer-lasting than the work I'd do to adapt the different housings.

Autolite Platinums were a worthwhile expense, as has been tracking down every ground on body to clean and protect. Added a couple to be on safe side, and added 2-ga batt cables. Never had a car that turns over as easily as this one now does.

Removed alternator and degreased after R & R on valve cover gasket. (Still a lot of degreasing to go).

 

[MustangSix]

If it comes down to replacing the rack, you might want one for a later Mustang GT. You may have to modify the hose connections, but the rack is faster (15:1 vs 19:1) and has better feel.

In fact, all the Mustang stuff is a bolt on, so if you can snag 87-up a-arms, spindles and brakes, you get better ball joints, bigger brakes and better geometry. Same for rear ends. Most 4cyl Mustang rears from 87-93 were either 3.27 or 3.45. One of those will add some snap to your Fairmont. Lowering springs, shocks, control arms......all just too easy.

Wheels, seats, even the dash will interchange with only minor mods. I've never tried, but it sure looks like Mustang sheetmetal will fit the front end of a Fairmont.

 

[xctasy]

Retro-fit the later bits, and you'll have em Foxed!

The cowl level is taller on the Fox Stang than the Granada/Fairmont. Aside from the wheelbase, very little is different underneath. The understeer and poor chassis dynamics of the first Foxes was totally fixed with the later Mustangs. Even 1984 LX 5.0 Fairmonts are really well connected vehicles.

 

[Anonymous]

So you all are telling me that it is literally a straight swap on the rear axle, right down to spring perches . . . that really does sound too easy.

Very glad to know the info. Once the car finishes its commuting duties at summers end (son goes back to college), will have to have a more serious look at this.

Have a copy of HOT ROD or other from a year or so back with a really great Fairmont in it, owner did all sorts of upgrades; I was thinking about it as I looked over a few Mustangs at Little Johns.

Getting the brakes and suspension upgraded is very tempting.

 

[BKNLINE]

So you all are telling me that it is literally a straight swap on the rear axle, right down to spring perches . . . that really does sound too easy.

As a proud owner of a '78 Friggin' Futura (factory 302 V-eight) I can emphatically say YES!

For even more fun, you can swap in the larger 11" rotors, calipers, spindles from an '87-'93 V8 Mustang along with the outrageously huge 1.3" front sway bar (compare to the stock V8 Fairmont's 1-1/16" front swaybar) and the fat rear sway bar. The rear lower control arms aren't as good since they have oval bushings but if you have some bucks you can buy good aftermarket or if you're lucky, find '83-'84 GT rear control arms.

Regarding the rack, it may be on it's way out. Mine started to be hard to turn to the right when cold and was normal warm but now it's hard to turn right at low speeds even when warm.

If you go with the Mustang GT rack, use the Mustang GT/V8 LX power steering pump too. They go together and you will need to get the GT p/s hoses as well.

If you want, you can also pick up Turbine rims or 10 hole style for about $20 each at a Pick Your Part Wrecking yard - maybe cheaper if someone is dumping their set.

Oh, if you want to get larger rear brakes, the Fairmont Wagon (and also '83-'86 LTD/Merc Marquis wagons) have larger rear drums - 10" I think. If you get the larger 11 Mustang GT brakes in front, I think the stock Fairmont master cylinder will still work fine.

For more braking power, you can upgrade to Lincoln MK VII front calipers with 73mm pistons. You will have to get a larger bore MC which may be a problem with rear drums since the MK VII's had rear discs. Usually if a person is converting to 4 wheel disc with MK VII calipers, they use the MK VII's MC and an adjustible proportioning valve.

Lot's of options with the First Fox!

(sorry for the length)

Dean T

 

[Anonymous]

Dean T: No such thing as too much specific information!

It can take quite a while to re-trace the tracks someone else has already covered, so you can bet I am glad for any and all info!

If any of you all have a good suggestion as to a periodical that covers these drivetrains/suspensions pre-1987 (versus late model Mustangs; I found that Fast Fords . . was late-model oriented too much),
I'd be appreciative.

Am working out cutting studs/grinding some clearance on Stovebolt carb adaptor; throttle/trans linkage; and a new hard fuel line for the 5200 replacement of the 1946.

Any suggestions for fuel pressure?

Tom's instructions include a proviso for 4-8 psi; I was thinking of adding a fuel pressure regulator set at four, or five or six psi per your suggestions. I'd rather keep it at lowest point. (And will test).

Thanks

 

[Anonymous]

i believe that 3psi was the ideal fuel pressure for the 5200 H/W

 

[Anonymous]

Got the 5200 up and running.

Had to clearance the bolt holes slightly on the Stovebolt adaptor and do a little work on the bowl exterior to get the oem studs/nuts to clear properly. With new studs and thick base gasket (Fel-Pro 60290, I think), the Pinto air cleaner worked fairly well even though the base is not an exact fit.

I cut out an extra-thick air cleaner base gasket to compensate and cut some 1/4-20 all-thread to make the top fit. Had to ball-peen the base slightly to clear the choke.

Had a water choke, but used the electric off of the 1946 to fit.

Used some old gate hardware to adapt the linkage. Stock configuration was about one-inch off. Pull is now opposite of oem overhead pull, so measured to give same underhead. Still have to adjust trans-kickdown (comes on a little early).

Any recommendations as to "when" the part-t kickdown ought to come into play?

And now that de-smog is complete (EGR on spacer remains, but is not connected), car has some real pep. Had a shop cut and weld the A.I.R. tubes closed, and install a pipe to replace the convertor.

Still playing with distributor spring combinations, but will wait for hottest weather to dial in for good. Currently using an xtra-lite and one stock spring (weights are marked 13 and 18). Not as much gitn'go as two lite, but no preignition either.

19 in/hg at 650 rpm (Neutral)(500 rpm Drive), about 10 BTDC; carb at 1.5 turns out.

Running manifold vac as carb won't run ported vac (must be blocked internally). It "flies" from of-idle thru freeway merge speeds, so the two part goal of driveability is at least half done.

Will have mpg figures at some point for the second, and car is good to go for the summer.

Appreciate all the help. Once she goes into garage for fall/winter, may start to look more seriously at performance upgrades. Shocks, struts, springs, tires and correcting camber -- as well as a new steer rack -- are definite.

 

[BIGREDRASA]

EGR has the effect of reducing knock when running lean. It is intended to not kick in at idle, especially when cold. It's important that the thermostatically controlled vacuum valve be operating properly, so the EGR valve doesn't open before the engine is up to operating temp. Simply suck on the ports to see which two are connected when hot and cold. Otherwise, it's hardly noticeable.
The other thing to look for is the thermostatically controlled valve that directs manifold vacuum to the distributor when the engine gets too hot. It's intended to raise your idle speed when in heavy traffic, and otherwise has no effect on performance. 8)

 

[Anonymous]

BigRed, I kept the EGR for the express purpose of being able to run a faster advance curve on this low compression-ratio engine. It is properly hooked up (even got a new Thermal Vacuum Switch to control it), but this carb is jetted leaner than the 1946 Holley and the EGR overwhelms it at idle.
(The valve works as designed).

As this 5200 has only manifold vacuum available at present (runs good enough for my son to get around for the summer), in the fall I'll find out what the problem is. If I can get it to idle well off ported vacuum then EGR stays for the reason above.

As to idle-speed compensation I would rather adapt a throttle kicker solenoid wired in with the A/C power, and re-curve the distributor if problems with extra hot running arise.

(Please don't mistake my appreciation of your comments).

I love (literally) the excellent air intake system on this car, so it is a matter of time before I take an adaptor over to a metalworking pro to keep the stock performance advantages of the original air cleaner housing . . but have it better looking than were I to do the work to adapt it.

Anyone have a recommendation on the adjustment of the part-throttle C-4 kickdown? I can do it seat of the pants, but would appreciate any input.

 

[Anonymous]

Short update:

Have gotten EGR functional. Still have some advance curve work to go (talked with the ever informative Tom Langdon at Stovebolt); drilled out part-vacuum to operate (was never apparently opened at factory for oem), and runs pretty good for this stage of the tuning.

Am going to back off on part-throttle kickdown screw to have it come in with opening of secondary carb barrel, see how that works.

Took an 80 mile, 60-mph trip recently and got 25 mpg. Though that isn't confirmed numerous trips/refills, it is encouraging.

 

[Anonymous]

79;
About that kickdown -

the Fairmont, with 1946 carb and C4 trans, is set at .080"-.100" clearance from the end of the screw when the throttle is fully open and the kickdown spring linkage is pressed down to it's limit. I set mine a little tighter, at .065" clearance, to let it pop into 2nd more easily when approaching the many hills out here.

I imagine the 'stang is close to that.

 

[lightnin-boy]

Hi,

Do you have any pics of your kickdown setup? I just re-installed my HW on my 65 Mustang, it has a 79 Zephyr engine so my throttle and kickdown arrangements are the same as yours. I'm happy with the 2 barrel, but I'm lugging around right now beacuse of the lack of kickdown... Any info you could share would be great!

Thanks,

Kirk