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1977 emissions equipment installation?

robbmic

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Joined
Sep 7, 2008
Messages
14
Hi, I was just digging in on some smog stuff. From what I can tell a 1977 Federal (Non-California) with an automatic and not delivered to a High Altitude DSO does not come with a Thermactor Air injection System.
 

Viperwolf1

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electron whisperer
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Aug 23, 2007
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24,316
Hi, I was just digging in on some smog stuff. From what I can tell a 1977 Federal (Non-California) with an automatic and not delivered to a High Altitude DSO does not come with a Thermactor Air injection System.

Not necessarily true. Look at the chart in post 16. There were 4 Fed/AT engine calibrations. 2 had air injection and only 1 of those was high altitude.
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
if you still have the original heads on the engine, if you had smog pump the heads would be drilled for either air tubes by the exhaust ports or a round hole in the end of the head where they would bolt on the check valve. If someone took off the smog pump they would have to plug theses holes which was very commonly done back in the day.
 

robbmic

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Joined
Sep 7, 2008
Messages
14
It has '69 heads on it now...The first one on the list of Federal/Auto is (21)(27) which is high altitude. So that leaves the (28) with Termactor or (29) and (30) without. My DSO is Dallas, TX so definitely not (21). The plot thickens...
 

robbmic

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Sep 7, 2008
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My Bronco does have the gas tank fumes evaporation reclaim system, maybe that means it is a (29)...
 

DirtDonk

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Nov 3, 2003
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Not sure. Every Bronco from mid-70 on up had the evap canister, so I'm thinking that DSO didn't matter on that particular component.
I recently found out that many full-size pickups did not have evap even up to about 77 or so. Which was a real surprise, since I thought all the light-duty pickups got the same basic smog stuff.
Apparently not, but the Broncos have all had it that I have seen.

Does not mean that there were not exceptions of course, and maybe someone can tell us if their original from '71 or later did not have the stuff.

Paul
 

robbmic

New Member
Joined
Sep 7, 2008
Messages
14
I sure appreciate the input. Looking at that engine chart from post 16 it shows (28) and (30) do not have the fuel vapor recovery system. I bought some 1977 Service manuals on Ebay, I will post any findings once I get them and do some more digging.
 

DirtDonk

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Hmm, I wonder if 28 and 30 were only for trucks over a certain GVWR (say, 5000?) and never associated with Broncos of those years then?
I suppose that's possible, but it's just a wild-assed guess designed to make the data fit the mold of what I think I know.;D

Paul
 

76 bronco J

Bronco Guru
Joined
Oct 20, 2005
Messages
1,480
Not sure. Every Bronco from mid-70 on up had the evap canister, so I'm thinking that DSO didn't matter on that particular component.
I recently found out that many full-size pickups did not have evap even up to about 77 or so. Which was a real surprise, since I thought all the light-duty pickups got the same basic smog stuff.
Apparently not, but the Broncos have all had it that I have seen.

Does not mean that there were not exceptions of course, and maybe someone can tell us if their original from '71 or later did not have the stuff.

Paul
>>> remember back in '77, 6,000 lb. GVW was the cutoff for heavy duty rating.... think '79/'80 it went to 8,500 lb. GVW for all states.... when 1975 EPA standards across the country came in every manufacture had catalytic converters on every vehicle rating under 6,000 lb. GVW... except one... Honda with the 1975 Civic-CVCC managed to passed the EPA tail pipe emission standards for vehicles rated under 6,000 lb. GVW without the use of catalytic converters.... for 1975 International rated all the scouts no matter what engine/model/springs pass the 6,000 GVW cutoff to avoid the new regulations.... 1975 wasn't so good for the bronco & F100 since they were rated under 6,000 GVW & couldn't pass light duty vehicle tail pipe emission standards without using catalytic converters.... 1975 F150 was in the clear for no catalytic converters since ford rated it above 6,000 GVW.... think even some full size cars/station wagons back then had over a 6,000 lb.GVW rating so they were classified as heavy duty & has less emission standards to meet....
 
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