Cracked exhaust manifold, with pictures!

Do I win some sort of prize? I have a hugely cracked manifold, and I still got 20 MPG on my last fillup!











This is on my 89 RENIX. I don't want to upgrade, I just want it fixed as cheaply as possible. What would be the best option? Braze it? Or buy a new one?

If you are dead set on it, weld it up.

Be sure to add a flexpipe after the downpipe, and check your motor and trans mounts or you will be pulling it off again (you will probably have to do that anyway).

joe_peters said:

If you are dead set on it, weld it up.

Be sure to add a flexpipe after the downpipe, and check your motor and trans mounts or you will be pulling it off again (you will probably have to do that anyway).

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I just phoned a local parts store, and looked online and couldn't really find any aftermarket manifolds for my jeep. =\

Looks like welding/brazing or finding a junkyard one will be the way to go.

Also since buying my jeep 20,000 KM ago I have put on Brown Dog motor mounts and a new tranny mount, so those won't be a problem. I was also thinking about adding some flexpipe, too, once I fix my manifold.

I've had pretty good luck welding them up (after a few failed tries). "C" clamp the manifold flange to something massive (I used a metal I beam). Mig the crack, I use a series of spot welds insted of a bead, the material seems to be an alloy and can act a bit like stainless and melt through pretty easy as it heats up.
Then torch the weld until red and let it cool slowly. Most of the *new* cracks that showed up again after a couple of years, were right at the border of the weld (on my fist tries). Dissimilar temper/hardness/expansion between the weld and manifold.
My screw ups were a (seriously) bowed flange once and on another occasion the flange was flat but the bolt holes were off by about a quarter of an inch on one end. After I learned to clamp it down before welding those problems disappeared (mostly).

I DON'T KNOW, BUT I'VE BEEN TOLD that the later 91-99 manifolds will fit, you just might have to have a new downpipe made (or adding the flexpipe would help that).

Here is the welded exhaust:




And the engine before putting it back together:




I plan on putting some flex pipe on the downpipe before the cat. Should prevent it from cracking. I think the new mounts will help, too. At least I hope

GUSSETS!!!! I harp on that when it goes to welding those. It works well. I did mine a year ago. I just started developing a leak though...down near the flange because I'm cheap and didn't replace the gasket when I welded it last year

Joshooha said:

GUSSETS!!!! I harp on that when it goes to welding those. It works well. I did mine a year ago. I just started developing a leak though...down near the flange because I'm cheap and didn't replace the gasket when I welded it last year

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I plan on selling this in a year anyways so it doesn't bother me if it leaks again haha.

mattbred said:

I plan on selling this in a year anyways so it doesn't bother me if it leaks again haha.

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Selling it in a year? Better be for another XJ:nono:

Joshooha said:

Selling it in a year? Better be for another XJ:nono:

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Absolutely! A 1997+ 5 speed. Swap in an NV242, a small lift, lil bit of armor, some performance stuff and call it a damn fine hunting/skiing mobile.

This thing of mine has been through hell and back and keeps me smiling though so I think it'll last me this skiing season.


Also, a note for anyone replacing their intake/exhaust manifold: Make sure your intake manifold is secure in the two studs. Mine wasn't, and when I torqued it to spec, it lifted it up. Wouldn't of been such a big deal but I had put a thin layer of RTV on it and it really pissed me off. Heh.

mattbred said:

Absolutely! A 1997+ 5 speed. Swap in an NV242, a small lift, lil bit of armor, some performance stuff and call it a damn fine hunting/skiing mobile.

This thing of mine has been through hell and back and keeps me smiling though so I think it'll last me this skiing season.


Also, a note for anyone replacing their intake/exhaust manifold: Make sure your intake manifold is secure in the two studs. Mine wasn't, and when I torqued it to spec, it lifted it up. Wouldn't of been such a big deal but I had put a thin layer of RTV on it and it really pissed me off. Heh.

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:cheers: