Novak Conversions Jeep Wrangler TJ engine mounts

Exhaust hitting drive shaft and pre-cat adjustments

emedlin

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The exhaust is about 50% on top of the drive shaft on my 2006 TJ 4.0L. I noticed it had self clearanced the exhaust pipe after I had bought it. It has started hiting again when braking probably because of the extra weight from the new bumper on it, or something has slipped. The bolts for mounting the precats to the manifold are pretty rusty. I tried to move two of them with a wrench and they will not move. My plan was to loosen them and try to move it over, as I had read on this site. My question is how much play is there? From looking at pictures of new manifolds and precats there doesn't look like any play. They bolt togther with the precat pipe going over the manifold pipe. The pipe ends do look rounded though. Do you just pivot the precats to where you want it and tighten it down, and the flanges don't actually touch all the way around?

I did reach my hand up by the flanges while pushing up on the passangers side of the exhaust pipe. I can fell the flangs moving apart on the drivers side, but I don't feel a gap between the pipes. I can actually move it enough to where the pipe is no longer over the drive shift. Should I just pull it as far as needed and secure the exhaust with a strap to hold it there?

The Jeep doesn't have the 3rd CAT. It is just a straight pipe with a metal hanger holding the pipe up by the passanger control arm. It doesn't use the hanger like it would if it had the 3rd cat.

I would like to have new precats and have a proper hanger installed this summer. But, for now I just need it to quite hitting.

One other question, does the factory exhaust have smooth bends or ridges coming down and around after the precats. Mine has ridges.
 
Hanger to control arm mount.
IMG20241231134151.jpg

Current position
IMG20241231134010.jpgIMG20241231134620.jpgIMG20241231134559.jpg


Me pushing on on it.
IMG20241231134615.jpgIMG20241231134609.jpg

I tried holding the camera in the same position while I pushed on it. If you would like to see other angles just let me know.
 
I had this issue with my new front suspension and it was a symptom of the axle being a hair too far to the passenger side. I had to adjust the track bar just a little to pull the axle to the driver’s side a bit and it centered it and fixed the interference. Check that out too if you haven’t already!
 
Loosen bolts, push to passenger side, retighten bolts. The first step is the hardest. Try penetrating oil.

Loosening would be ideal. Should I expect it to move at all if they are all the way tighten down now? Just seems strange I can move it without doing anything to the bolts. I can feel the flangs move further apart, so it isn't bending the pipe. I only have one exhaust related code, P0153.
 
Like @Granite suggested make sure your axle is centered. Drop a weight over the side above the tire on each side and match the tread equally on each side. I used a magnet with a string and a screw at the other side. Stick the magnet on the hood and hang it above the tire.
Next loosen the exhaust bolts as needed all the way back(mini cat too). Use a 2x4 to block the pipe where you want it, then tighten up all the bolts.
Fixed.
 
Like @Granite suggested make sure your axle is centered. Drop a weight over the side above the tire on each side and match the tread equally on each side. I used a magnet with a string and a screw at the other side. Stick the magnet on the hood and hang it above the tire.
Next loosen the exhaust bolts as needed all the way back(mini cat too). Use a 2x4 to block the pipe where you want it, then tighten up all the bolts.
Fixed.

Actually just went out and tried something similar before I saw your post. I used a string and washer and hung it on one of the fendor screws that hold the fender flares on. Looks like I am about 1 to 1.5 inches to far to the passanger side. It does have an adjustable track bar. I need to look up how I adjust it though. Would it need an alighnment done after I adjust it?

Passenger side
1735674557710.png

Driver side
1735674572757.png

Track bar
IMG20241231143120.jpg
 
Last edited:
Not sure on the alignment but it’d be best that you do. Pretty sure your steering wheel will be clocked wrong. That can be done easy at home, no need to pay to have it done!
Instructions are here on the forum. I bought this to assist in the alignment.
https://a.co/d/a3OIT0h
But you can do it from scrap steel if you’ve got some laying around.

1.5” will help clear your exhaust a bunch😃
 
So, maybe my fenders aren't perfect or something. But, I decided to measure from the frame to the outside of the tire. The driver side is 21ish and the passanger side is 20ish. So, it is the opposite of the string and washer test? Is messuring from the frame a valid test?

Passanger side
1735676865176.png
Driver side
1735676857163.png
 
After eye balling with wife and kid we agreed it doesn't look centered and should be moved over toward the drivers side. However, the track bar nut will not move. It doens't look rusty though. I have it soaking in some PB Plaster.
 
Loosening would be ideal. Should I expect it to move at all if they are all the way tighten down now? Just seems strange I can move it without doing anything to the bolts. I can feel the flangs move further apart, so it isn't bending the pipe. I only have one exhaust related code, P0153.

You shouldn’t be able to move it if it’s tight. The interface between exhaust manifold and y-pipe is akin to a ball and socket joint. Adjust it and tighten it so that it holds its position. While you’re at it, you should remove the y-pipe to check the condition of the catalyst mesh inside the pre-catalytic converters considering you have that P0153 code.

Centering the axle will help as well. You will need to adjust your drag link if you adjust the track bar length.
 
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I got the nut off the track bar. I had to double wrench it to get more torque. Not much room to turn it. I had to make maybe 1/8 of a round at a time. Now it doesn't want to fall out. I thought it would be stuck and and finally just pop loose. But, I am having to turn the bottom and it is slowing coming out. Almost like it is threaded in. Since this an aftermarket track bar I assume around 100 ft/lbs of torque when I put it back on. Not that I can get my torque wrench on it.
1735690073496.png
 
I got down to where turning it didn't make it move. After that I just turned the steering back and forth some and it feel out. Guess it was just in a bind. My new problem is no matter how much a bounce the front end nothing changes. When I check where the tires are at with the washer and string they are in the same place. :mad:
 
I got down to where turning it didn't make it move. After that I just turned the steering back and forth some and it feel out. Guess it was just in a bind. My new problem is no matter how much a bounce the front end nothing changes. When I check where the tires are at with the washer and string they are in the same place. :mad:

I think at this point bouncing the front end isn't likely to change it. Sometimes you need some ratchet straps and something anchored into the ground (i.e. a steel pole).
 
The axle location might have something to do with your driveshaft/exhaust rubbing problem but not much.

Just seeing how much space you have between the exhaust and the oil pan, along with you mentioning that the 3rd cat (and probably the metal hanger attached to it) are missing, I'll post what I did to fix the opposite problem

When I first got my (then) stock 2006 TJR I noticed that one of the downpipes was actually rubbing the oil pan. I could sway the pipes side to side but they wanted to stay close to the oil pan and it took a bit of bending of the metal hanger at the 3rd cat to get the down pipes away from the oil pan. I also spent some time tightening the manifold to downpipes bolts which weren't exactly loose but tightening did seem to help keep everything in a better place.


Here you can see maybe 1/4" gap. I couldn't find a picure showing the paint burnt off the oil pan
IMG_20220522_201031958_HDR.jpg



I also couldn't find a picture of where it ended up but it was, and my still be good 1 inch of space
 
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I got down to where turning it didn't make it move. After that I just turned the steering back and forth some and it feel out. Guess it was just in a bind. My new problem is no matter how much a bounce the front end nothing changes. When I check where the tires are at with the washer and string they are in the same place. :mad:

Rachet strap from one side of axle (knuckle) to other side frame. No need for a ground anchor.
Use the frame to measure, not the flares.
Also, loosen the adjusting jam-nut before disconnecting the bar.

I don't think your pipes are factory, so YRMV.
 
The axle location might have something to do with your driveshaft/exhaust rubbing problem but not much.

Just seeing how much space you have between the exhaust and the oil pan, along with you mentioning that the 3rd cat (and probably the metal hanger attached to it) are missing, I'll post what I did to fix the opposite problem

When I first got my (then) stock 2006 TJR I noticed that one of the downpipes was actually rubbing the oil pan. I could sway the pipes side to side but they wanted to stay close to the oil pan and it took a bit of bending of the metal hanger at the 3rd cat to get the down pipes away from the oil pan. I also spent some time tightening the manifold to downpipes bolts which weren't exactly loose but tightening did seem to help keep everything in a better place.


Here you can see maybe 1/4" gap. I couldn't find a picure showing the paint burnt off the oil pan
View attachment 582777


I also couldn't find a picture of where it ended up but it was, and my still be good 1 inch of space

If that is the stock pipe my 06 TJR is not stock, but has some cheap one that doesn't seem to fit very well.
 
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Rachet strap from one side of axle (knuckle) to other side frame. No need for a ground anchor.
Use the frame to measure, not the flares.
Also, loosen the adjusting jam-nut before disconnecting the bar.

I don't think your pipes are factory, so YRMV.

I will see if I can dig out my rachet strap tomorrow. Not sure if I have heavy duty one though. As for measuring the frame. If you look above I tried the washer / string method from a bolt on the fender that holds the flares on. I also tried the measuring from the frame. The washer shows I need to move the axle to the drivers side which would give me a litle more room. Measuring from the frame shows I need to move it to the passanger side giving even less room. Maybe where I put the tap measure on the frame isn't the same on each side or something.

I didn't lossen the adjusting jam-nut on the bar before disconnecting the bar. I didn't think that would help any, but I will try that next time if I every take it off again.

To move the axle to the drivers side I need make the track bar shorter. Although I only have few more threads to turn to make it any shorter. Also based on where it is sitting right now I am going to have to make it shorter just to get it back in. I don't suppose anyone recognizes the brand based on this pic or the one I posted above. The bar is silver if that helps any. :LOL:
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Novak Conversions Jeep Wrangler TJ engine mounts