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Topic Review (Newest First)
07-22-2013 08:56 AM
Cashcrazy I finally got this finished this weekend. A word of advice for others in to install the EGR tube on the intake/exhaust while everything is off, then install both at the same time. I learned the hard way. I completely installed everything while I was waiting for my replacement egr tube. When it arrived I couldn't get the threads to line up no matter what I tried. Next I loosened the manifolds and thought I had the threads started. Wrong. I took it all back out and installed the tube with the manifolds out. Now it's all back together with a new gasket, motor mounts, and power steering pump. Tonight I will put on the MC2100. I have my fingers crossed that at least that will go smooth.
07-18-2013 09:24 PM
Mbclark Always something. I've been registered non operational for a few years while my Jeep under went transformation. I'm road worthy and going for the emissions test Saturday. As long as all goes well she'll be back on the road next week!!
Hopefully you will too.
07-18-2013 08:37 PM
Cashcrazy I found a used tube and it's on its way via the mail. I continued forward with the reassembly this evening. I knew my power steering pump was leaking a little, but I was going to put off replacing it because the Jeep has turned into a money pit. That was until tonight when I grabbed the pump and was covered in PS fluid. So it's another trip to the parts store tomorrow. The Jeep continues to get newer.
07-18-2013 08:20 AM
Cashcrazy I sent a couple of emails and am waiting on a response. The problem is that there is no finger tightening the exhaust side with my current tube. I put heat to it and was able to get it spinning again, but I still need a wrench on it because its hard to turn. I sprayed it out with carb cleaner and then a PB Blaster bath. That helped, but still too much friction for hand tightening. I guess this evening I will take it all back apart, which I really didnt want to do. Then install the tube on the exhaust manifold and reassemble.
07-18-2013 01:08 AM
Mbclark Any luck finding the tube? I hear they're getting hard to find.

You may have to loosen up those manifolds to install the tube. The manual says to finger tighten the tube to both manifolds, tighten manifolds to correct torque then tighten down the tube. This prevents the tube from twisting and cracking.

I hang the exhaust manifold by the studs(finger tight), then install the tube on the exhaust manifold. Next hold intake in place and start the threads on the tube. Install and torque all bolts then snug the tube down.
07-17-2013 08:55 PM
Cashcrazy I had a productive evening on the Jeep. The manifolds are bolted up and torqued properly. I ran into one problem with the EGR bypass tube(tube that connects the exhaust to the intake manifold). Twenty four years of heating and cooling on the exhaust manifold welded the threaded part to the tube. I let it soak in PB Blaster overnight with no luck. Now I am on the search for another one.
07-16-2013 02:12 PM
wasomma 1989 models:

Nos. 1 and 2 = 30 foot pounds
Nos. 3 through 12 = 23 foot pounds
07-16-2013 12:03 PM
Mbclark If the head and manifold surfaces are freshly machined you an run no exhaust gasket and that's why it includes two. I found that the intake gasket hit the exhausts bifold and wouldn't lay flat on the head. I just went they this about a month ago. I used the big gasket that seals both and haven't had any leakage.
07-16-2013 10:03 AM
Cashcrazy Thanks for the response. I was worried that stacking the two gaskets would create more opportunity for leaks. When I took it all apart the intake had a fiber gasket and the exhaust manifold was mounted directly to the block with no gasket. I hope to have this bolted up this evening.
07-16-2013 09:04 AM
Mbclark Just use the one big exhaust gasket. That gasket has the same part number all the way back to 1970 something. Some older applications didn't use the exhaust gasket, just the intake. Again use the one big gasket and do not use sealer.
07-16-2013 08:27 AM
Cashcrazy I am ready to start putting this back together. I took my time and cleaned the mating surfaces very well. I picked up the FELPRO MS90949 gasket set and have a couple of questions. The set came with a gasket that is fiber on one side and metal on the other and a regular fiber gasket for the intake manifold. The metal/fiber gasket covers the entire mounting surface on the block for the intake and exhaust manifold. Is the fiber intake gasket supposed to be installed on top of the metal/fiber gasket? That's how I plan to install, but wanted to make sure the gasket set didn/t come with an extra gasket for a 4.0. I have also read the debates on sealer or no sealer on these gaskets. My plan is to install dry unless someone talks me out of it. The PO used a sealer on the last intake gasket and it leaked. Thanks in advance.
07-12-2013 07:31 PM
Decoy_58 I found one at rock auto dot com for 55.00 oem specs
07-09-2013 10:44 AM
Cashcrazy One year, unlimited mileage warranty. No name brand on it, I assume it's cast in Mexico.
07-09-2013 10:06 AM
Mbclark Is there a warranty on the new one? If so if go with that one. And yes the Jeep inline motors are prone to manifold cracks.
07-09-2013 09:38 AM
Cashcrazy I found a used and the cheap new manifold for about the same cost. I am a little worried about the quality of the new manifold, but also know the used one is 20+ years old and could crack. Any opinions on that? Since it's a cast iron manifold I guess it's a roll of the dice for which will last the longest. I have been a small block chevy man for the last 15-20 years and never had a manifold crack. I have pulled several sets from engines sitting under a tree for years and still never had a cracked one. Maybe I have been lucky and this Jeep is making up for it. Was the 258 manifold prone to cracking? I found a lot of threads about others with the same issue.
07-09-2013 02:48 AM
Cashcrazy Yes I have the 4.2
07-08-2013 11:30 PM
Mbclark You have the 258 4.2l correct? I think Joker misread your post. The 4.0l 242 has a flexible portion built into the manifold. Not really an option for our motors.
07-08-2013 10:44 PM
Cashcrazy Joker, what do you mean by flex part? Are you referring to where the flex hose connects?
07-08-2013 10:36 PM
jokerchief462 A 2.5l you can use the straight cast manifold no problems. But for the 4.0 you need to look at the replacements that have the flex part where they usually crack.

Good replacement instead of the cheapest and do it once.
07-08-2013 10:15 PM
Mbclark Not all manifolds have gaskets. Some are machined surfaces that are sealed by carbon. I'd run a gasket. And $70 sounds good but not sure on the quality. I paid $40 for a used one.
07-08-2013 09:40 PM
Cashcrazy Thanks for the info. The cheapest new manifold I can find is at jcwhitney for $70. Does anyone have experience with their cheap cast iron manifolds? Are they truly OEM quality?

Also, I found the reason for the exhaust leak... There was no gasket on the exhaust manifold.
07-08-2013 08:59 PM
Mbclark
Quote:
Originally Posted by sfhusser View Post
The flexible hose from the exhaust manifold to air cleaner is a preheated hose for when the engine is cold. The exhaust to under the carb is the EGR bypass tube. If you have to get smogged you need it. And yes your exhaust manifold is cracked.

I'd suggest replacing it with headers, but mine have been a royal PITA.
Guess I should of read before I typed
07-08-2013 08:58 PM
Mbclark Metal hose between manifolds is the EGR tube.

Flex hose is a preheated hose. It allows the engine to pull some warm air in. I've talked to guys who have been in extreme cold and had the carb ice up because that hose was disconnected. Doesn't serve too much of a purpose in warm environments. It's part of emissions here in California.

And that manifold may be able to be welded but that's just buys some time. You want to make sure it's not warped if its warped you may as well replace it. Not too expensive.
07-08-2013 08:56 PM
sfhusser
Answers

The flexible hose from the exhaust manifold to air cleaner is a preheated hose for when the engine is cold. The exhaust to under the carb is the EGR bypass tube. If you have to get smogged you need it. And yes your exhaust manifold is cracked.

I'd suggest replacing it with headers, but mine have been a royal PITA.
07-08-2013 08:40 PM
Cashcrazy I guess I will keep this thread going with my progress.


I removed everything and now I have a couple of questions. First, the pic below is the exhaust manifold. Is this a crack and needs replaced or a common sight from years of heat? If this needs replacing has anyone purchased lately? I am looking for the cheapest option to get it running. It has broke me...



Last questions for now.... Can someone explain what purpose the metal flex hose that runs from the exhaust manifold to the air cleaner serves?? Also the metal tube on the intake below the carb that connects to the exhaust manifold.
07-08-2013 08:11 AM
Cashcrazy Does anyone have any secrets for tightening the bottom bolts? I used a long extension, a wobble joint, and accessed them by going under the intake. I'd love to know if there is an easier way.
07-07-2013 06:58 PM
Cashcrazy I got all the bolts from the intake and exhaust off and have it pulled loose. My power steering pump has had a slow leak so ill probably go ahead and replace it since I have it all unbolted. Tomorrow evening I am going to disconnect the coolant hoses, wiring, etc from the intake and pull it completely out for a thorough inspection. The bottom bolts were a real PITA to remove.

All of this is happening for my quest to have a smooth idle.
07-07-2013 12:17 PM
Cashcrazy I am going to start pulling the manifolds this evening. Sooner or later there will be nothing left to replace at the pace I am going.

I really appreciate you sharing this info.
07-07-2013 10:52 AM
Mbclark
Quote:
Originally Posted by Cashcrazy View Post
I should add that I just put in a MC2100 carb. While the carter was off I had a couple of loose bolts causing a vacuum leak on the intake. The loose bolts felt like they were slightly more than hand tight. So I set the torque wrench to 22ft lbs to make sure everything was to spec and now I have black smoke pouring out of the manifold somewhere. I haven't fine tuned the carb yet so its rich. I don't know if I always had the exhaust leak or if I created it torquing down the three loose bolts I found.


Attachment 269912

Here's the sequence. You may want to pull those manifolds and check to make sure they aren't warped and you have no broken bolts. A fresh gasket is always nice too.I just replaced both of mine when I put the new motor in.
07-07-2013 09:14 AM
Cashcrazy I should add that I just put in a MC2100 carb. While the carter was off I had a couple of loose bolts causing a vacuum leak on the intake. The loose bolts felt like they were slightly more than hand tight. So I set the torque wrench to 22ft lbs to make sure everything was to spec and now I have black smoke pouring out of the manifold somewhere. I haven't fine tuned the carb yet so its rich. I don't know if I always had the exhaust leak or if I created it torquing down the three loose bolts I found.
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