Exhaust plug

[komoto123]

So i recently took off the air pump from my 2.8 v6, along with it the tubing that traveled to the exhaust manifolds. Problem is i now have two holes. What do you guys recommend? Plugging or Buying new headers.

 

[dangerranger83]

If you haven't done it, duraspark your truck.

Sent from my SPH-L710 using Tapatalk

 

[komoto123]

I plan on doing the duraspark but no part of the duraspark conversion says anything about the holes in my exhaust manifold. Tech library only gives aftermarket headers, not anything on stock mani.

 

[simpler=better]

I've welded cast iron before, if you don't want it to crack preheat on a grill to at least 300*, weld with SS rod, and then leave it on the grill to cool, slowly over a couple hours.

 

[komoto123]

Thanks simpler=better i will think about that

 

[RonD]

The holes in the exhaust manifolds should be threaded?
Just get plugs for them.

O2 sensor was only used for EFI or some "Smart Carburetors", it would be needed by both.
It is not an "emissions" part, it is a tuning part.
It would be a threaded hole so if you are going to a manual carb then just thread in a plug

 

[komoto123]

The holes are not threaded in mine. The air pump pipe just popped out. Perhaps they have rusted smooth i do not know. It is a 25+ year old truck.

 

[RonD]

I have seen the metal expansion plugs(freeze plugs) used to close off those types of holes.

 

[komoto123]

I am not sure how a freeze plug would work as they pop out from pressure. Unless i was to pop them in from the inside but that is nearly impossible.

 

[1986fordranger]

my old 84 had the the air pump deleted, and all the pipeing, what the guy I got the truck from did, was JB weld an old spark plug into the holes, seemed to hold up well without any leak's for the time I had the truck, just another option

 

[dangerranger83]

The holes aren't threaded. What I did was keep the piping on them just cripped and bent the end over a few times and never had a problem.

Sent from my SPH-L710 using Tapatalk

 

[komoto123]

I can't just bend it over. But regardless thanks for the idea, i never thought of doing it that way.

 

[RonD]

I am not sure how a freeze plug would work as they pop out from pressure. Unless i was to pop them in from the inside but that is nearly impossible.

It would work fine, cooling systems average 12-18psi of pressure and expansion plugs work fine.

Non-turbo exhaust systems should never run with that much internal pressure, stock manifolds rarely get above 10psi, headers 5psi.
In a perfect exhaust design the pressure at each exhaust port should be slightly less than outside air pressure, this pulls exhaust out of cylinder faster, but that would be perfect and it isn't a perfect world, lol.

When you run from a smaller diameter pipe to a larger diameter pipe(collector) you increase velocity and reduce pressure.
So when the exhaust pulse from one cylinder hits the collector its velocity increases and pressure drops, this pulls pressure from the other cylinders pipes, and keeps over all pressure down.

The common myth about engines "needing" back pressure came from people putting in larger diameter exhaust pipe manifolds and losing power, so they think "I made the flow too good so engine must need back-pressure to get more power"
But what they had really done was to increase the back-pressure by reducing the velocity with the larger pipes.

 

[Tulsa Ranger]

1984 2.8 manifold plugs - air pump lines rusted off

I had the mac truck sound effects when the metal lines from the air pump rusted thru and broke off.

I went to the salvage yard with one end of the broken tube and found a bolt that was just small enough and yet large enough to almost thread it in.

I picked up some high temp JB weld putty and puttied up the bolt and threaded it into the exhaust manifold. Not pretty, but effective. Gas mileage on my 84 has always been lacking. My regular driver was a Civic Si hatchback.

So no truck does close to the Honda.

Hope this helps.

Tulsa Ranger