My 85 F-250 has 2 air pumps run off the alternator pulley.

On a recent trip the belt broke and I drove 400 miles without it. The engine seemed to have more power without it.

Question is:
1) What do the air pumps do ? I think thay clear vapor from the
crankcase but am not sure.

2) Can you run without them or will it ruin something else?

 

you'll ruin and clog your catalytic converters, and in states with emmisions inspection it is illegal to unhook the air pump.

 

The truck was originally made to burn regular leaded gasoline so has no catalytic converters.

 

an 85 made to run leaded gas????? air pump and no cat??????

 

I have the same set-up on my 86 F-250. It has no cats and dual air pumps. I took the belt off and it runs a lot better. From what I've gathered, you shouldn't hurt anything at all. I'm not even sure why Ford put the pumps on if there aren't any cats on these trucks but hey, I guess common sense is rare in the real world.

 

Yeah, the heavier trucks were exempt from emissions for years, so why the air pumps? A friend in high school used to surprise people all the time in his 3/4 ton Chevy. 454 4bbl, dual exhaust with no cats from the factory. Yeah, that thing ran!

 

upto 86 they were CAT exempt b/c of some heavy truck emissions and that. (Mainly b/c of leaded gas and no CAT were really HD enough to withstand the heat/pressure).

They DID have air pumps, mainly b/c that would lower some of the emissions, but it wouldn't lower the CO [why u have a cat is to convert the CO to NO.

 

I have an `85 F350 with the 460, air pumps, and no cat. It had the other emissions equipment such as EGR and such too.

The air pumps are used to add oxygen to the exhaust stream to help further burn any unburned gases as they leave the motor. On an engine that had a cat in the exhaust it would help reduce the richness of the exhaust making the work on the cat easier and extend its life.

Removing the belt is not going to cause any problems unless there is a cat. In that case the rich mixture of the exhaust will shorten the cat life considerably. Without a cat it will make passing any state emissions testing tough, but it won’t hurt the motor or cause drivability problems. The exhaust mixture will just be a bit richer.

Removal of the equipment is possible but takes some work. I have removed everything except the crossover tube that is connected to the back of each cylinder head. To remove that you need to be able to plug the holes that are left and that would require more room than is available with the motor in the truck. The other issue is the individual tubes that go to the exhaust manifolds. Removing them can be difficult depending on how seized they are in the manifold. They can be left in place.

Taking everything else out, and carefully making sure you have blocked all vacuum sources that were part of the system, is what I did. To remove the huge bracket assembly that holds the air pumps will require a different alternator bracket set up. I watched for one on ebay that ended up coming off a car 460. It required that I use a spacers (about one inch each on three bolts) to move it out enough to clear the sub-frame and align the v-belt pulleys. I made up the spacers from aluminum round stock and bought longer bolts from the local hardware store.

The engine compartment is much more open and everything is easier to get to now that the air pumps and all the other emissions stuff has been removed. Plus, it resolved a lot of vacuum leaks because every piece of rubber hose and rubber diaphragm was dry rotted thus providing a leak.

Good luck,

Mark