New manifold/pipe questions

[84eaglelmz]

Today on the way to work i blew the manifold and the pipe connection right out on my 84 wagon  . Its freaking loud now. Does anyone know how hard it is to change the manifold and that first pipe? and how to do it? Do i have to remove the intake and like all 50304 vacuum lines to do this? or should i go to walmart and buy a pair of vice grips and clamp it back together  JK!

where is the cheapest place to get the manifold? or could i put some headers on this? any info will help me a lot. thanks!

[Bird-o-Prey]

Unless the manifold is super rusted out, I suspect that it is just the down pipe that blew out.  So, you don't have to remove anythig from the top of the engine to replace it.  However, it you blew out your exhaust manifold gasket, you will have to pull the carb and intake manifold as well to replace it.  If replacing the gasket set, you wil have to start by draining the coolant since most eagle have it routed through the intake to help warm up the air when the car is cold.  Then you will have to disconnect the carb and remove that as well as some sundry electrical connections.  Unbolt the donw pipe from the exhaust manifold using as much penetrating oil and swear words as will allow the bolts to finally let go.  Then unbolt the manifold(s) from the block.  Clean them up with a wire wheel in a grinder and replace the gasket set.  Installation is in the reverse order.  Apply more foul language & beer liberally as needed!  I would suggest taking pictures and writing yourself some notes as you remove to help you when trying to put it all back together.  It really ins't all that difficult, just a bit time consuming.

Cheers

[mudkicker715]

One of my eagles had a vice grip to compensate for a broken exaust bolt to the down pipe. worked perfect.

kinda need more info

[Jurjen]

There could be some exhaust manifold bolts loose and a part of the gasket blown away.
On top of that, the first and last bolt/stud of the manifold like to break off.
The nuts between the manifold and header pipe are hard to reach (I used a metric 14mm wrench that I grinded in two).
You will need a 3/8" socket wrench set, 1/2" wil not get in between the inlet and outlet.
You  have to remove a lot of vacuum hoses (just label them and make pictures).
I removed the throttle assembly below the carburettor too and had to drill out the first and last studs of the manifold.
After you reinstalled everything (new gaskets for the manifold) make sure to retighten the bolts after 100 and 1000mls and then once a year.

[carnuck]

If a chunk of the gasket it gone, try to loosen the studs (be careful not to snap them)
I've wrapped wire around the stud (between the nut and the flange) to pull the pipe up. I've even put hose clamps one to take up the gap and cut the noise to tolerable levels.

[84eaglelmz]

I'm almost certain its the bottom pipe that blew out or the gasket between the two. I doubt the manifold gasket to the motor is bad, its not all that rusty to be honest, The nuts come right off as well, When i put my manual choke on i used one of the nuts, easy as cake. Maybe ill just do the whole thing new while I'm removing everything anyways, that will save the penetrating oil and swear words needed for the job. Ill take a good look at it this week to see what exactly went bad and update on what to do.
everything I'm doing will be from under the hood correct and not under the car even if its the bottom pipe? I didn't look much at it, just the million hoses under the hood.

[mudkicker715]

The exast pipe to the manifold has no gasket. as far as disconnecting the manifold from the pipe the front nut is acessable from the top the back nut takes creativity.

[carnuck]

Actually, 80-'82 COULD have the donuts, depending which intake/exhaust manifold is in there. The early 1 piece ones have the donut (I have one in my scrap pile)

[mudkicker715]

My experience with those years was an 80 kee, my 82 concord, and a replacement motor from a supposed 82 cj. all had no donuts.

[captspillane]

They changed the Iron Duke manifold in 1982 to have a donut. My 1981 does not. The 1981 has a donut like shape protruding from the actual casting that mates directly to the top of the downpipe. The 1982 casting is totally different and it has a thin metal pipe stuck in it that is supposed to reinforce the donut. I went through three donuts before realizing the difference and scrapping the 1982 version with much joy and jubilation.

Its entirely possible some numbskull at AMC made the change on the 258s for awhile then too. It wouldn't take long to realize it needed to be changed back.

[84eaglelmz]

If i do replace both the manifold and the pipe, anyone know the cheapest place to get one?

[captspillane]

The original cast manifolds are available. A used one off a nest member would be best. Its not something easy to ship because the EGR tube is usually rusted fast to the manifold and slightly rusted to the intake. You should get a manifold with the EGR tube still intact and attached. If you got a new one chances are you'd destroy the EGR tube during removal and there are no replacements available. You would be forced to put a plug in that hole or get quite creative.

If you want to upgrade your whole exhaust I suggest a brand new stainless 4.0 header for a 1992 Cherokee.  The downpipe is relatively easy to make and any competent exhaust shop will not blink an eye at making one. They will not be willing to modify your front axle hangar. It just takes some trimming with a grinder. I also attached a picture of Priya's project car (its not my picture) that shows a very similar exhaust construction as I will use for mine. The only difference in mine is that I added a stainless steel mesh vibration damper directly in front of the transfer case/transmission junction because that is where it is rigidly fastened.

I attached a picture of the exhaust manifold I just bought off the evil bay. Its stainless and made fairly well. Its superior to the stock units because it has the baffles in the typical crack locations that plague the stock units. It only cost 88 dollars total for a brand new one. If you get this one, DO NOT USE THE INTAKE/EXHAUST GASKET IT COMES WITH!

[carnuck]

Looks like it'll be harder to change the trans! Mine crosses in front of the trans pan.

[84eaglelmz]

The new ones do not have the egr tube with them? and is it needed? My TVS hasn't worked in ages anyways so I doubt its even working now? With the Jeep 4.0 headers what did you do with the EGR valve on that?

[captspillane]

On my Motorcraft 2150 Spirit I had the exact same stainless steel headers installed by the previous owner. He gave up on the car and sold it to me at a great loss mostly due to the intake/exhaust gasket. The one it comes with develops huge cracks as soon as it is heated up to normal operating temps. Use a high quality Fel-pro gasket.

For PA inspection I needed a visibly complete EGR system. I welded in a O2 sensor bung. In my case I purchased a new small section of exhaust pipe, about 8 inches long, with the threads already welded in for about 12 dollars. Its more common to drill a hole in the exhaust and weld a special nut (about $3) to the pipe. Either one an exhaust shop will be very familiar with because all new fuel injected cars need multiple O2 sensors. They have an odd fine thread count but are fairly universal at the threads. I then used pipe connections bought at a hardware store to adapt those threads down to 3/8 threads. I used a stainless steel flexible line intended for a toilet to go from there to the EGR exhaust input hole. It passed the visual emissions inspection.

Inside my pipe connections I reamed them slightly larger with a drill bit and then ran a tap inside it. I then threaded a bolt into it until tight. I then used a grinder to cut the bolt flush with the start of the threads. My EGR valve would have been operational if that invisible plug wasn't there. I didn't want to risk the toilet hose rupturing.

I drove it that way for four months until the engine got pulled for an MPI conversion in my SX4. I'll need the O2 sensor bung for that so it was a temporary fix that also completed several necessary steps toward my long term fuel injection goals. I suggest doing all this if you want a 4.0 eventually but sticking with the original cast piece if you will stick with a 2150 long term.