Emissions era air injection tube rusted off manifold

[Carmine]

I did do a search on this, and cannot believe I didn't turn up any results. I would think this problem is common as dirt on the emissions era formal Big Blocks.

The passenger side exhaust manifold has a hole at the rear, very near where you would pull the transmission dipstick from. Of course this tubing is relatively thin and by now has probably rusted away on most any of these cars that are not hermetically sealed. Of course when it rusts all the way off, you have a fairly good exhaust leak.

In a perfect world you would simply remove the bolt that attaches this pipe to the manifold, replace it with a solid blank of metal and bolt it back on again. But in the real world, this fairly small bolt snaps off leaving the thread in the manifold.

With a little bit better accessibility, one could probably pound a plug into the hole. But not much room to swing a hammer between the firewall and exhaust manifold. I'm hoping I can find a correctly sized Bolt and create enough of a thread to get it to stay in place within the remains of the tube/ hole in the manifold. Guess I'm just asking if anyone has been here already and has a better idea for a fix?

Photos of the tubes mounting flange and broken bolt attached below.

 

[68HemiRR]

I did do a search on this, and cannot believe I didn't turn up any results. I would think this problem is common as dirt on the emissions era formal Big Blocks.

The passenger side exhaust manifold has a hole at the rear, very near where you would pull the transmission dipstick from. Of course this tubing is relatively thin and by now has probably rusted away on most any of these cars that are not hermetically sealed. Of course when it rusts all the way off, you have a fairly good exhaust leak.

In a perfect world you would simply remove the bolt that attaches this pipe to the manifold, replace it with a solid blank of metal and bolt it back on again. But in the real world, this fairly small bolt snaps off leaving the thread in the manifold.

With a little bit better accessibility, one could probably pound a plug into the hole. But not much room to swing a hammer between the firewall and exhaust manifold. I'm hoping I can find a correctly sized Bolt and create enough of a thread to get it to stay in place within the remains of the tube/ hole in the manifold. Guess I'm just asking if anyone has been here already and has a better idea for a fix?

Photos of the tubes mounting flange and broken bolt attached below.

View attachment 660202

The HP engines didn't have the AIR. They used these plugs.

 

[commando1]

I think this situation is ideal for JB Weld. No?

 

[57fury440]

Maybe, like you said, find a bolt that almost fits and screw it in, only use some JB Weld around it to hold it in and seal it. If the manifold was easy to get off, then I would tap the hole and put in a plug.

 

[Just Carbs]

Brass pipe plug.

 

[Carmine]

I think this situation is ideal for JB Weld. No?

What I read says JB Weld is good up to about 500°. My concern would be the expansion and contraction of a chunk of cast iron that gets that hot. You can watch it at night and it basically shoots fire.

 

[Carmine]

Maybe, like you said, find a bolt that almost fits and screw it in, only use some JB Weld around it to hold it in and seal it. If the manifold was easy to get off, then I would tap the hole and put in a plug.

This is basically the idea I have so far. Luckily a piece of tube came out this morning when the exhaust was cold, so I have a good idea of the diameter now.

 

[Carmine]

Brass pipe plug.

Giving this one consideration as well, one challenge is that it would be very hard to swing a hammer between that exhaust manifold and the firewall. However I was thinking a 2x4 against the firewall and some kind of screwjack to press it in.

 

[Just Carbs]

Giving this one consideration as well, one challenge is that it would be very hard to swing a hammer between that exhaust manifold and the firewall. However I was thinking a 2x4 against the firewall and some kind of screwjack to press it in.

Threaded brass pipe plug.

 

[Elvis Lean Burn HP]

Interesting topic. I have the same leak same location on my 400 LB Newport.

I’ve acquired 67 c body manifolds to replace the existing manifolds in my 1977 Newport and run duals

My leak is very small at this present time.

 

[fury fan]

I doubt you have clearance, but pipe taps in that dia (1/4 or 3/8?) would be pretty short and you might be able to tap it for JustCarbs pipe plug.
But - starting threads always seems difficult unless you have a straight shot and can put a double-handle tool on them.
Doing with a wrench or socket/ratchet always ends up being too wobbly.

What I would look for - a fine-thread self-tapping screw in the appropriate size, and drive it in with a ratcheting wrench, so you can put a finger on for pressure. (still easier said than done)

 

[Boydsdodge]

1 Find non air pump manifolds and swap. Getting rid of the air pump system completely.
2 Take air pump manifold off, remove broken bolt and plug holes with threaded plugs or the block off plate.

 

[Elvis Lean Burn HP]

planning on doing what you just said related to changing the exhaust manifolds. Picked up a set of 67 c body manifolds. Visual they discharge very close to the LB manifolds.

 

[fury fan]

1 Find non air pump manifolds and swap. Getting rid of the air pump system completely.
2 Take air pump manifold off, remove broken bolt and plug holes with threaded plugs or the block off plate.

Yes, but how many studs will break removing the manifold?
And if removing it, no need to buy different manifolds, he can drill/tap the one he has.
And should only be hte passenger-side, IIRC this isn't an air pump system, it's a pulsed/vacuum tube that pulls air from the air cleaner?

 

[Dads300]

The guys running 5.4 powered f150s in the rust belt use some kind of furnace/chimney repair compound to repair broken/rusted out exhaust manifolds. I would think packing the hole with that stuff would last a lifetime. Good to a brazillion degrees.
Travis..