Save that manifold! (caution dial up)

[Tim]

I bought another jeep a week or so ago, and got a pretty good deal on it. One of the reasons I got it for
less than normally paid, is it had a terrible exhaust leak. I've fooled with enough later model jeeps that I
knew pretty well what the problem was - sure enough a cracked exhaust manifold. Most 4.0L jeeps have this
problem at some time. The manifold is made of tubing rather than cast, and it cracks from stress.

A new manifold is $250 to $400 depending on if you buy stock replacement or go with Borla or the like. Since
this jeep is intended to be a low budget car for my in-laws to tow behind the motorhome, I did not want to
invest that kind of money in one part.... there are a few other things I'm going to have to fix as well. I've seen some
pictures in the past of manifold repairs, so decided to try my hand at it. It turned out really great - no leaks at all.
There were two breaks in the manifold - one of the six primary tubes was broke, and one of the two secondary
tubes was broke. I jambed some junk steel between the tubes and seal welded all the way around where they
come together - adds strength and eliminates the leak between the tubes that I could not get to.

Pics are big so you can see detail.

[mgerdes]

Tim as always you do great work.

[mike_777]

now that's a weld job. gj

[bpmudluvr]

i wish mine looked that good. have a big ole crack in bout the same spot i think.

[Elliott]

This is great. I have always had a hard time seeing what they were welding when looking at other websites concerning this. I have a question concerning this. I plan on putting a Borla on in January but until then would it be possible for me to use something like JBweld on the manifold. The reason I ask is because I am not a welder so I wouldn't be able to do a true weld. I assume JB weld can handle the heat. I know this would not be a true fix but should get me along until Jan.

Thanks

[98TJSport]

i tired JB Weld on mine, i didnt do a real good job at cleaning the area off and it didnt work. the crack is still there. i reckon if i had cleaned it better it would have worked better, it would be real hard to clean it while still in the jeep. if you were to remove it i would just take it to a fellow jeeper to weld it for you, im sure somebody would love to do it for ya.

[Tim]

Taking it off and putting it back on is way harder than welding it. Any muffler shop would probably weld it for you once you had it off though. I'm out of gas but would be willing to weld it once I get some - if you take it off and bring it to me. I really don't want any part of the remove and install. :)

[flyj]

I had a leak in mine, but I just went to U wrench it and pulled one of theirs. I think the cost was ~$20.

[98TJSport]

hey Tim is that still holding up?

[nbpmotorsports]

OK, I found a way to save the exhaust manifold from cracking, real simple. "Flex or braided exhaust tubing" between the y pipe and the cat. This allows your motor to move under hi revs and takes a lot of weight off the exhaust manifold. Its cheaper than replacing the manifold and you can mount your exhaust higher.
This trick also helps out on headers from coming loose(plus using header locking bolts).
Ken

[Tim]

Still holding. Mine is getting louder - probably going to have to do it soon.

[98TJSport]

how often do you drive this "other" jeep?
would it be beneficial to weld up a manifold that isnt
already cracked? flexj brought up the fact that you can
get a used manifold from a junkyard for pretty cheap
and then have somebody weld that up for you then put
it on your jeep.

[Tim]

The other jeep gets driven daily - it's my father in laws main car. The miles are highway - no offroad since the repair.

My jeep gets driven rarely, but when it is it's for lots of off-road. I've also been thinking about fixing another one up and just doing a swap - no reason it should not work as long as the years are close. I think there were a few changes through the years in shape - get the wrong year and your exhaust pipe might not bolt up.

Just a suggestion - you have to remove the intake to do this swap. If you have an older YJ like mine look for a late model intake and swap it out too. It's a more rounded shape instead of the log style my 91 has - is supposed to gain you 25 horse or so. Get two jobs done at once. Drive the jeep for 20 minutes or so then re-torque the bolts while it's still warmed up - helps prevent gasket failure.

[98TJSport]

yea i saw in a mag where a 99 and up intake will gain you some
HP and that they are usually in junkyards for cheap.
ill have to look into that when i finally get around to fixing my
exhaust manifold, its been cracked for almost 2 years now.

[Y-Hike]

Tim I have aftermarket header sitting in my garage that has a small crack at the collector if you want to fix up and use as a spare.