I have the original L48 motor in my 73 and I'm considering removing the Air pump. Is there any power gains from doing so? Or should I just leave it on?

Thanks.

 

I removed my air pump about six months ago. Not for power gain but to clean the clutter under the hood. After removal I did notice a slight increase in power and a small increase in gas mileage.

Anytime a rotating mass is belt driven, horsepower is required to drive it, no matter how slight.

The removal of the vaccum hoses connected to the pump cleaned up alot of small leaks and sure cured the idle roughness.

The whole removal process only takes about 30 min., the hardest part of the job is finding the six 3/4x20NFx1/2 bolts to plug the air inlets into the heads.

Good luck,
Jack

 

Thanks Jack,

So I'm taking it off.. It must make a small difference...
Good to know, and it'll reduce clutter aswell.

I wonder if Home Depot has those 3/4x20NFx1/2 bolts...

Thanks again.
Cheers

 

remember to keep it all so when you sell it the next guy can't say stupid stuff like its not original so i'm not giving you that much money.....

 

The plugs for the exhaust manifold are available at any NAPA Auto parts store. I removed mine and there's a slight gain in engine response.

 

Thanks for the replies guys..
I'm taking it off, and I can imagine it'll probably run smoother, and now look uncluttered..

I'll keep the sacred part..You never know who'll say... (Oh, It's not original now!) LOL

Cheer

 

Just Be Aware That All Of The Tube Fittings May Not Easily Come Loose. First I Would Try To Get Them All Loose Before Going Too Far.

I Had This Problem With My 73. It Became Obvious That I Was Going To Damage Them So I Found A Set Of Replacement Manifolds.

 

Let me know how it goes. I,m debating the same issue with my 73. Just worries me at how tuff it is to remove the air tubes.

 

Augustus,

I am in the same boat, wondering whether or not to remove the air pump from my 73. Actually, I removed it but I can't get the tube lines loosened from the manifolds. i'm gonna keep trying liquid wrench around the threads and trying to go that route but i'm probably just better off replacing the manifolds.

I work at Home Depot and at our store we don't have any 3/4" bolts that are a 1/2" in length. Better go the NAPA route.

Will pre-73 manifolds bolt up to those L48 heads?

Keith

 

mine squeals

I was thinking about just removing the belt. Any problems in doing just that?

 

Hello,
I have a 73 454 that has already had the smog pump removed. The previous owner left the exhaust maniforld tubing intact, and where the tubes/pipes come up toward the smog pump location, he connected them with a hose that goes across the thermostat and EGR valve.

My question is similar to several others in this thread. How difficult would it be to remove the tubes from the manifolds? Someone mentioned soaking the bolts in liquid wrench. My fear is trying to remove them, and ending up rounding the heads on the bolts. For those of you who have removed them was it pretty easy, or did the original tubes/pipes get damaged in some way.

And thanks for the tips on where to find the bolts to fill in the holes after they are removed. If all else fails, a set of headers may do the trick.

kdf 1973 454
kdf 1986 L98

 

The "best" replacement SB exhaust manifolds with NO A.I.R. holes are the '74 L-48 automatic ones, or '75 & '76 ones(they had the air from the smog pump piped to below the heat riser, so they have no A.I.R. tube holes). Also most '77-'79 L-48 automatic cars did'nt have smog either, so the manifolds out there are plenty & reasonably priced.

Many of these A.I.R. fittings are frozen and rusted very bad from aging. Even IF you manage to get the fittings out, the manifold threads may come with them NOT letting you put a threaded plug back in

 

I can't remove my air pump here in Illinois. My car wouldn't pass emissions testing. I wouldn't remove the pump anyway; removing the belt provides the same results.

 

How about removing the Air Pump and keeping the tube that sticks out the exhaust manifold?
This way it doesn't disrupt the manifold itself, and is easy to put back on..
The only thing is trying to get a Bolt to cover up the tube..

What do you guys think?

 

I live in Illinoise also but I have antique plates so I don't have to worry about emissions.

 

Another question. Woudn't it be just as hard to remove the manifolds also? What if we cut the air tubes than maybe use a socket wrench to remove the bolts??????? Would that work better?

 

Removing or replacing the manifolds would be my last option.
I don't know about cutting the tube...I'd probably want to keep that intact...Maybe remove the tube from the manifold...or just plug it up on the top of the tube via a bolt...what do you guys think?

 

I have disabled a few smog cars. Not that I am opposed to the equipment, but because it does not function properly and correct replacements are not available.

If you want to keep it looking stock you can leave the pump/belt alone and put a few holes in the underside of the rubber hoses going to the check valves. They do not need to be real big but just big enough to let the air escape without making any noise at idle/cruise. The trees can be removed from the manifolds using heat/PB Blaster/and vise grips if they are stuck bad. The stainless steel tubes inside the manifolds can be removed. The SS tubes can be replaced by a short #10 screw from the Home Depot. This will seal off the exhaust gasses from flowing back up the trees. Put them in the trees pointy side up with thick grease to hold them in place untill you get the tree installed. Block the hose going to the diverter valve using a small ball bearing or a screw. This keeps it looking stock but still does not destroy any expensive to replace parts.

If you do not care about how it looks, you can pull the stuff off and buy some straight pipe thread plugs from NAPA, coat them with never sieze and install them in the manifolds. The threads are unusual because they are straight pipe thread, not tapered pipe thread so your local hardware store will not carry them.

You could always keep the system on the car and make it functional but the problem with that is the diverter valves are not easy to find and they seldom function after all these years even if NOS. They have ruptured diaphrams that cause vacuum leaks and can cause afterfiring when you close the throttle.

Hope this helps.

-Mark.

 

Thanks for the help everyone!

I'm not worried about keeping things stock under the hood but I do want to keep the original parts in case someday they are needed (should resale be a consideration?) Anyway, I think I will be trying to locate some manifolds w/oout those pesky trees sticking out b/c I don't think those fittings are ever coming out of my manifolds.

I've definitely bitten off a lot with this car but as I have read here and in magazines and talked with others it's not going to be an impossible task--but close to it

Glad that there's a place like this to gain knowledge and find help.

Keith

 

They are NPT pipe plugs at any decent hardware store.