1977 emissions equipment installation?

[77OregonBronco]

Does anyone have pictures of what the smog equipment is supposed to look like on a 77 Bronco? I'm trying to reinstall the equipment and am having a hard time finding reference pictures. Thanks

 

[72_EB]

These should help. Have fun. ;D

 

[jckkys]

Apparently the Bronco in the above photos was from Cal. or other emission control happy state. My '77 did not have air injection or as Ford calls it Thermacter. It did have EGR and catalytic converters.Without the Thermactor the engine looks much different.

 

[77OregonBronco]

Thanks for the pictures!

Interesting. I though all 1977 Broncos required air pumps for Federal emissions standards. I'm in Oregon, so I'm guessing I'll need it for a 77?

 

[72_EB]

'77 Denver DSO.

Pictured carburetor is on Ebay now actually (shameless plug). Search "Motorcraft 2150 Colorado" as keywords and it ought to come up.

 

[jckkys]

I bought mine in Lake County Ill. and avoided the Cook County (Chicago) emissions rules. Az. varies by county too. A visit to the Az. MVD compliance center taught me at least in Az., they only care that EGR and converters are there. Where are you?

 

[77OregonBronco]

I'm in Portland Oregon, so I think they might want me to have it, but I'll check.

 

[jckkys]

I just found a '77 4Wheel Drive and Off Road magazine article, testing a '77. The truck photographed has '77 Mich. plates that was likely delivered to Mich. Like mine there was no air pump. Portland has been controlled by hippies for many years, so they may have Cal. emission laws. You'll have to check with MVD.

 

[77OregonBronco]

Seattle DSO dealer 74J523 built March 1 1977. Any ideas on what it should have had?

 

[DirtDonk]

Fer sures:

Catalytic converter. Single exhaust.
EGR
Duraspark Ignition
Fully enclosed air cleaner housing with cold-air snorkel to the corner next to the battery. No holes drilled into it for "extra air flow" or it will fail most visual inspections.
Vacuum/temp controlled hot air tube from the exhaust manifold to the snorkel.
Hot air tubes from the exhaust manifold to the carburetor choke
Evaporative system, including the plastic charcoal canister on the firewall.
Lots and lots of vacuum tubes going to unknown dark areas. Including:
Front, back and bottom of said air cleaner housing. Distributor advance mechanism, at least two, if not three "timed" temperature controlled vacuum switches in various parts of the intake manifold and the air cleaner housing and such.
Some carbs had a float bowl vented to the charcoal canister. Some didn't. By '77 I'm not sure if they all did, or just CA, or just what.


Maybe for sures, but maybe nots:

Thermactor system. As mentioned, not all EB's had them. Even in CA they varied from year to year starting in '66.
Dual-diaphragm distributor maybe. I've heard that in '77 they went back to a single diaphragm, but don't have a verification on that rumor.
Maybe a carburetor with float bowl vent running to the charcoal canister.


Allowable upgrades in many jurisdictions:

Headers as long as they do not cause the removal or defeat the purpose of existing smog control devices.
Aftermarket air cleaners as long as they're sealed to under-hood areas, include the cold-air intake function, and all vacuum and heat control devices are still functional.
Carburetors? Usually no changes allowed in most areas. Some might allow a 4bbl if the connections and fittings are the same as the smog carb, but most places don't want you to mess with that.

That's about all I can think of. Your basic '77 would have had a crapton of stuff on top of the engine. Mostly connected by vacuum lines, but several connected to electrical circuits which you hopefully still have as part of your wiring harness.
At the very least, do your best to connect vacuum lines to whatever they're supposed to fit, and hope you don't have too much missing. For Early Broncos, around here at least the books are not so detailed in what exactly is supposed to be under the hood as later trucks and most passenger cars. So if it "looks" like it's all there, you might just get lucky and pass the visual tests even if a few small components are still MIA.
The real proof is in the sniffer if they do that. That's where a lot of missing stuff and hotter cams tend to show their colors.

Good luck.

Paul

 

[jckkys]

Some things I know for sure having Az. laws in Pima and Maricopa counties enacted soon after I moved to Az. in 1978, and finding myself having to comply. I bought the truck new, so The OE smog equipment was all there.The distributor is single diaphragm and uses the ported vacuum connection on the 2150. There was an inline plastic delay or one way valve in the line. There was no Thermactor ( air injection pump). It had 1 catalytic converter. The carb. bowl vent was capped. The hot air butterfly on the air cleaner snorkel got vacuum after 2 temperature valves in the air cleaner. There was no TVS anywhere, even in the EGR vacuum line. Otherwise it was as Paul said.
.

 

[Rox Crusher]

Requirement for smog pump was determined by the DSO.

When I registered my Nashville DSO 77 in Colorado I was told that all of CA (starting in 76?), any large city, or a high altitude location required smog pump.

 

[jrwyant]

Mitchell's 1977 Truck book (from my local library) has diagrams for a number of different "calibrations"--I don't know which my '77 is, as the valve-cover sticker is painted over.

 

[jckkys]

The Mitchell's diagrams are most informative. Diagram #9 is correct for both auto. and manual Fed. Bronco engines.Diagrams 11,13, and 14 are incorrect. This one shows the plumbing for air injection, with no pump. This is an obvious error on it's face. My own experience also conflicts with this diagram. My '77 was built with a manual transmission. I swapped in a C4 in the early '80s. I know for a fact that my manual equipped truck had the emissions equipment in of diagram #9. Diagrams 11,13 and 14 have the air injection plumbing, including the anti back fire valve or bi-pass valve. This only exists with an air injection pump. My '77 and the magazine test truck didn't have it. I may have had the PVS at the rear of the intake. I just can't remember seeing it. To do a correct restoration I would duplicate diagram #9, plus the PVC in the oil filler cap plumbed to the front of the carb spacer. The choke had both a hot air and electrically heated thermostatic choke cap. My air cleaner also had a blue plastic vacuum valve called a cold weather modulator, that you may not need in places that don't get as cold as northern Ill.

 

[DirtDonk]

I just assumed (big potential for error there!) that the pump was left off of the diagrams for simplicity and clarity, making it easier to see all other hose and tube routing.
Perhaps that's incorrect, but as you pointed out those other components are only used with a pump. Maybe back then they assumed (they can't be prosecuted for doing that after so long;D) that anyone looking at the diagrams would know that and also assume.

Hmm, I think that's the first time I've used the "A-word" three times in one post. Not a good way to start the day!

Paul

 

[Viperwolf1]

Those diagrams are only showing vacuum line routing. They are not showing all the emissions equipment.

 

[jckkys]

I've gone through my Motor Manuals, Chilton's '66-'86 Bronco Guide. Chilton's '66-'77 Bronco Guide, and the '77 Ford Truck Shop Manual. I found that the ported vacuum switch or PVS in the rear of the intake actuates the EGR when the coolant reaches 98 degrees. I will stick to my memory that ported vacuum from the carb functions the single diaphram vacuum advance. This hose had a spark delay valve in it. There was no PVS in the front of the intake or on the thermostat housing like many other Ford engines. The Cal. version had so many differances from the Fed. 49 state trucks that to make a Cal. compliant Bronco from a Fed. type would be very difficult and expensive.

 

[77OregonBronco]

Thanks everyone for the great information. There certainly is a lot of knowledgable experts on the forum!

 

[robbmic]

I know this is a really old post but the diagrams are vacuum diagrams, not full emissions diagrams. The Thermactor pump and hoses are not vacuum.

 

[904Bronco]

I know this is a really old post but the diagrams are vacuum diagrams, not full emissions diagrams. The Thermactor pump and hoses are not vacuum.

What do you need to know?