1967 California Emissions

[DirtDonk]

Good to see it again. Thanks for the update and pic.

 

[tatersalad]

I believe all 289 V8 broncos in California had smog pumps, they went away in 69 to 72 with 302.

 

[jamesroney]

...And a pic of the roadster.

 

[Ovalis]

I believe all 289 V8 broncos in California had smog pumps, they went away in 69 to 72 with 302.

I think 73 as well. Never seen a 73 with a smog pump and they didn't list a part # for the pump in the parts book as well.

 

[tatersalad]

I think 73 as well. Never seen a 73 with a smog pump and they didn't list a part # for the pump in the parts book as well.

That was what I thought also but to be safe from keyboard warriors I went 72.

 

[WheelHorse]

With out a catalytic converter, why would one pump air into the exhaust? I really question the sweet science of how much continued burning of HC's really took place in an open exhaust.

I wonder if this was one of those just-make-the-feds happy by diluting exhaust so it appears to be cleaner.

 

[DirtDonk]

Air pumps came first by several years, and I believe they did what they were supposed to. Maybe well, maybe not, but they did do something.
You're not just diluting the exhaust, you're burning it (hopefully). There really is a little bit of combustion that "can" happen with the right circumstances. Which includes injecting oxygen right at the port where any unburned fuel is most likely to post-combust and take just that little bit extra out of the exhaust. Remember in some cases they were retarding the ignition timing as well, so that might have caused more unburned fuel to exit into the exhaust, which made it seem I'm sure like some added air into the ports might just encourage it to burn.

I'm sure it was not as effective as the better combustion chambers and tuning that came along later, and converters and all that other stuff they came up with too, but it was a start.
In some cases they made smog-pump engines with higher heat materials in the exhaust valves, exhaust pipes, and more hardened valve seats due to the extra heat that was generated by the after-burn effect. And probably not in a small part to retarded ignition timing as well?

Air pumps were used from about '66 (not sure of all models, but those were the first ones I saw) and cats didn't come around until '73 or '74 or so if I remember. So they were using the pumps perhaps as the first go at the problem, or perhaps as you say, a stop-gap measure until the planned for cats could arrive.

And after cats they still injected air into the ports, along with air directly into some converters. But not all got the direct air injection. Not sure what the criteria was for your cat to get air, or not to get air, but they did not all have the tubes from the pump plumbed right into their side like some did.
It was a brand new science so to speak. Of course they were just learning what worked and what didn't. And yes I'm sure it was to keep the feds happy to a point too. But as far as I know it did work.
At least to a point. And hey, any improvement was a step in the right direction towards the next step.

I know we lost a lot of joy from the mid-seventies, to the mid-eighties when things really started to turn around. Was a ten year learning curve, but I personally love what the results were. I'm sure a lot of LS and Coyote owners like the results, and 'll take my stock 1998 Explorer engine over my stock '68 or '71 engines any day of the week!
With cats, but thankfully no air pumps.

Paul

 

[BajaFresh75]

I probably have it all. I've been hoarding everything '67 for my NLA U13 for years! If I have a duplicate I'll let you know.

 

[Broncobowsher]

Air injection works. It is still used to this day. Not as prevalent as it was in the past. But there are still new engines that have an electric driven air injection pump.

If you ever ran an engine without an exhaust manifold or even just manifolds and could get fire to shoot out the exhaust. That fire happens once it picks up some fresh oxygen from after the engine.