77 Smog Pump

[Go Devil]

My 77 has all the emissions accessories in place but does not have a belt on the smog pump. What issues would arise if I put a belt on the pump? Is there any maintenance that needs to be done on the egr valve at certain intervals?

 

[904Bronco]

My 77 has all the emissions accessories in place but does not have a belt on the smog pump. What issues would arise if I put a belt on the pump? Is there any maintenance that needs to be done on the egr valve at certain intervals?

Assuming the pump is not frozen or having issues internally, there should be no issues putting a belt back on it.

EGR valve has no maintenance... It is a vacuum operated valve.
The ports to and from it can get plugged with carbon deposits and you may need to clean them out. Apply vacuum to it (not running) to see if it can hold a vacuum. Apply vacuum to it while it is running and the motor should start running poorly, to the point of dyeing...

 

[jckkys]

You may not even need the smog pump, or Thermactor as Ford called it. Only Cal. and some municipalities required it. Mine was from Lake Co. Ill. and never had the pump. EGR will plug up as 904 said.

 

[G's Baja Bronco]

DO you need to pass emissions? if not, leave both alone! EGR will rob power and those pumps freeze!

G

 

[Go Devil]

Thanks for all the responses. I don't have to pass emissions anymore, have antique plates. I will leave it alone if it affects performance. I was just looking for a way to clean up exhaust fumes without affecting performance. The pump spins freely, originally delivered to GA. The three times I went through inspection I passed.

 

[garberz]

Put a Cat on it, there's been a few that did that to help with the fumes.

 

[jckkys]

The emission equipment required for a specific DSO is something I couldn't learn. Even the Az motor vehicle dept. compliance center, didn't know. They said CATs, EGR, and PCV, were all my '77 needed. Now I too have 5 yr. classic vehicle insurance, to avoid the sniff inspections and save a lot of money.

 

[G's Baja Bronco]

that is why I went with my 75 EB and let go of my 76 Ramcharger (440cid beast) in Cali smog every 2 years was a PITA!

fumes? cats will really kill performance! I hear a few new stangs with 5.0's taking out their cats locally! I still have mine on my GT500, it is noisy enough!

 

[Go Devil]

I had a new muffler installed a couple years ago and the shop installed a cat, said they had too.

 

[ezbngreen]

My 76 has all the smog equipment and passed California emissions test. How much noticeable power could I be losing by having a pump and EGR?

 

[904Bronco]

My 76 has all the smog equipment and passed California emissions test. How much noticeable power could I be losing by having a pump and EGR?

In all honesty I do not think you will notice any change in performance... You have to look at the whole engine picture... Late 70's Smog heads, cam, old school Cat design, etc. are the issues you need to over come

 

[Broncobowsher]

Thermactor (air pump) puts air into the exhaust. Doesn't change how the engine runs. The exhaust still being hot enough to burn, but just lacks the extra oxygen, does burn itself cleaner. Dirt simple emissions control device. You can spin the air pump by hand, it doesn't take any noticeable power to run.

EGR is only a part throttle cruise application. At full throttle it is closed and does not affect power. At cruise it increases cylinder pressure without adding any extra fuel. Due to the inert properties of already burned exhaust it helps control NOx emissions and the added cylinder pressure improves fuel economy. The bad part is the tuning on carbureted applications can be problematic. How much flow, at what times, just isn't the best at times and has a reputation for drivability issues. If it works good hooked up it is worth keeping hooked up. But working poorly it can cause issues. More issues can arise by unhooking it as the carburetor should be tuned for the EGR to be functional at part throttle. Removing the EGR can cause part throttle drivability issues. Full throttle the EGR has no vacuum and is closed, just like it isn't there.

Cats are great at cleaning up exhaust. Older carbureted applications almost always have an air pump as part of the operation. They burn off the un-burnt parts in the exhaust. They need enough free oxygen to do so. EFI engines with O2 sensors have enough feedback that the engine can pump enough oxygen into the cats to keep them working. On a carbureted engine the tune still has to be pretty close. Try to clean too much dirty exhaust and the cats can overheat and melt down.
Old school pellet bed cats are a noose in the exhaust system. Modern honeycomb cats flow really nice. Todays aftermarket high flow versions don't have negative impacts to flow. Most of the "more power" claims by removing them are from the added noise you get.

 

[904Bronco]

Thermactor (air pump) puts air into the exhaust. Doesn't change how the engine runs. The exhaust still being hot enough to burn, but just lacks the extra oxygen, does burn itself cleaner. Dirt simple emissions control device. You can spin the air pump by hand, it doesn't take any noticeable power to run.

EGR is only a part throttle cruise application. At full throttle it is closed and does not affect power. At cruise it increases cylinder pressure without adding any extra fuel. Due to the inert properties of already burned exhaust it helps control NOx emissions and the added cylinder pressure improves fuel economy. The bad part is the tuning on carbureted applications can be problematic. How much flow, at what times, just isn't the best at times and has a reputation for drivability issues. If it works good hooked up it is worth keeping hooked up. But working poorly it can cause issues. More issues can arise by unhooking it as the carburetor should be tuned for the EGR to be functional at part throttle. Removing the EGR can cause part throttle drivability issues. Full throttle the EGR has no vacuum and is closed, just like it isn't there.

Cats are great at cleaning up exhaust. Older carbureted applications almost always have an air pump as part of the operation. They burn off the un-burnt parts in the exhaust. They need enough free oxygen to do so. EFI engines with O2 sensors have enough feedback that the engine can pump enough oxygen into the cats to keep them working. On a carbureted engine the tune still has to be pretty close. Try to clean too much dirty exhaust and the cats can overheat and melt down.
Old school pellet bed cats are a noose in the exhaust system. Modern honeycomb cats flow really nice. Todays aftermarket high flow versions don't have negative impacts to flow. Most of the "more power" claims by removing them are from the added noise you get.

Well said.

 

[ezbngreen]

Well said.

Very well said. Thank you for the responses.

 

[Broncobowsher]

Those are common cracks in the 9" under a Bronco.
Weld and go.