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New Exhaust Manifold

J

Jeff1

NAXJA Forum User
Location
New Palestine, IN
I'm getting ready to install a new exhaust manifold to replace my cracked stock one. Can anybody give me advice?
Are those stock replacement manifolds with the flex bellows any good or should I go with a header?
Any install tips would be great too.
 
what year????

just follow the torque order and specs in the FSM....
 
Get a shorty 9/16" "Flex" socket (short socket with inbuilt universal joint,) as it makes the rear screws so much easier.

Use LocTite #272 or nothing on those screws. Torque to 19-21 pound-feet.

A light, even coat of RTV copper on both sides of the gasket won't go amiss.

If you can, replace with silicon bronze screws - better retention of strength over heat cycles (get them from Fastenal.) Also, be sure to reuse those little "dish" washers that came off of the screws. If you can't get silicon bronze fast enough, replace with SAE Grade 5 screws (SAE 8 will lose strength too quickly - I have verified this experimentally.)

The collector stud nuts should be threaded 3/8"-16 - I don't think that changed (although I could be wrong. Please let me know if I am.) Replace with brass if possible, SAE5 if not (if they're metric, try to find ISO 8.8 nuts - for the same reason as the SAE5 screws.)

I'm sure there's more that I'm not remembering right now - it's late. I've covered this in detail several times before, tho, so search for my posts on the subject.
 
I just put PaceSetter Headers in my '89. Seem to be doing pretty good, but I haven't been able to drive it all that much since I put them in however.

Even if you don't put headers in make sure you use a good gasket! The gasket that comes with the PaceSetter Headers in garbage! It needs to have metal seals around the exhaust outlets and have a steel core laminate.

If you do go with PaceSetter Headers the thickness of the flange on the headers differs from the thickness of the flange on the intake. This causes a sealing problem with the bolts that hold both the intake and the headers. PaceSetter sells some spacers that they have machined to make up for this distance. If you kit does not have them DO NOT install the headers with out them. It will only cause you to do more work in the end (replacing the gasket). When I called them they said that they come included in the kit of hardware (they weren't) and they also said that it clearly states in the instructions that they need to be used (not a single word about them).

Also make sure you keep all of the bolts tight that hold both the exhaust manifold and the intake manifold on. Jeeps are know for having exhaust leaks around the exhaust manifold. It's not a bad idea to check the bolts often. Especially right after your new manifold/headers are installed. And then probably check them everyother oil change.

Hope that helps you out. I wish I would have know all that before I started mine.....
 
All headers will crack at some point down the road same as the OE one did. The newer manifolds for the HO's have the bellows and will last longer. E-bay has ones for less than $100 shipped to you with all the stuff. You can take the studs out of you old manifold and put them in the new one so you don't have to mess with the bolts that come in the package.
 
MJR said:
All headers will crack at some point down the road same as the OE one did. The newer manifolds for the HO's have the bellows and will last longer. E-bay has ones for less than $100 shipped to you with all the stuff. You can take the studs out of you old manifold and put them in the new one so you don't have to mess with the bolts that come in the package.
Click to expand...

Are the Ebay ones reliable? I've seen them on there for a long time and I've been reluctant. However, I've noticed most aftermarket manifolds all look identical to the ones on Ebay. I'm sure their better than the one I've got now with the crack in it.
 
Jeff1 said:
Are the Ebay ones reliable? I've seen them on there for a long time and I've been reluctant. However, I've noticed most aftermarket manifolds all look identical to the ones on Ebay. I'm sure their better than the one I've got now with the crack in it.
Click to expand...

Well the E-bay ones look just like the Dorman ones you can get at most parts stores. If they are still around most offer a lifetime warranty which you may or may not need. The only pain would be having to do the labor over again. I do not really see much difference based on the complaints I see from installers of the fancy/expensive headers and how long they last. I am considering getting 1 or 2 for two of my Jeeps.
 
5-90 said:
Get a shorty 9/16" "Flex" socket (short socket with inbuilt universal joint,) as it makes the rear screws so much easier.

Use LocTite #272 or nothing on those screws. Torque to 19-21 pound-feet.

A light, even coat of RTV copper on both sides of the gasket won't go amiss.

If you can, replace with silicon bronze screws - better retention of strength over heat cycles (get them from Fastenal.) Also, be sure to reuse those little "dish" washers that came off of the screws. If you can't get silicon bronze fast enough, replace with SAE Grade 5 screws (SAE 8 will lose strength too quickly - I have verified this experimentally.)

The collector stud nuts should be threaded 3/8"-16 - I don't think that changed (although I could be wrong. Please let me know if I am.) Replace with brass if possible, SAE5 if not (if they're metric, try to find ISO 8.8 nuts - for the same reason as the SAE5 screws.)

I'm sure there's more that I'm not remembering right now - it's late. I've covered this in detail several times before, tho, so search for my posts on the subject.
Click to expand...

So do the bolts replace the studs altogether? Meaning the manifolds are held on with all hex head bolts and no studs? I'm confuseD! :banghead:

With silicone bronze I don't need to lube or loctite the bolts or torque them more/less than the FSM states?

Thank you for your help!
 
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