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Need ya'lls opinion...

Ben824

NAXJA Forum User
Location
Woodstock, GA
Ok guys ya'll are usually very helpful when I need assistance trying to make a decision. I have been trying to fix and replace things on the Jeep simply to improve the overall condition of the Jeep since it has 200,000 miles now and it is 14 years old.

I have been battling cracked headers for a long time cracking one after another after another I think I am at 8 now including the stock one. I have replaced both motor mounts and added a flex pipe in the down pipe. I checked the transmission mount and it isn't dry rotted or torn but it does move around a bit but I figured since it was rubber that there was no problem there.

Here is my question, can a rubber mount over time become too soft and allow for too much movement?

If so I definitely want to replace it and I might do it anyways just because it is so old now. My next though is should I go for a stock replacement? Or go for a polyurethane? I have had polyurethane motor mounts and those transmitted WAY too many engine vibs into the Jeep for my taste. I am very ADD and sitting in traffic listening to all the different rattles in the Jeep make noise about drove me insane. So I threw back on some stock rubber ones from the dealership and solved that problem. My concern with a polyurethane transmission mount is that I would get vibrations transmitted into the Jeep.

So what do ya'll think? Please be nice.
 
When you replace the manifold are you replacing it with stock style replacements or are you going aftermarket like APN and such? If it's stock style replacements that might be part of the problem as their design isn't that great causing the problem in the first place. Also you said that you put in a flex piece in the down pipe, where exactly did you put it in at as the most common place seems to be where it crosses under the engine allowing the side to side movement of the exhaust instead of worrying about front to back movement.
 
When you replace the manifold are you replacing it with stock style replacements or are you going aftermarket like APN and such? If it's stock style replacements that might be part of the problem as their design isn't that great causing the problem in the first place. Also you said that you put in a flex piece in the down pipe, where exactly did you put it in at as the most common place seems to be where it crosses under the engine allowing the side to side movement of the exhaust instead of worrying about front to back movement.

I went with a Banks header the first time I replaced it and it has a lifetime guarantee so I just keep getting it replaced for free under warranty so it never costs me anything but my time. However now it has gotten to the point where I am replacing it every 6-8 months which is very annoying. I had the flex pipe installed at a local exhaust shop and I told the guy what I was trying to do and he suggested to put it in after where it crosses over. I too thought it would be better to put it in where it crosses over but this guy had exhaust know-how that I didn't (or so I thought) so I didn't question.
 
Is the header cracking at the same place every time or is it different places each time? If you have rubber in the engine bay you should have rubber on the tranny. I have always read that you should have the same material in the different mounts.
 
Is the header cracking at the same place every time or is it different places each time? If you have rubber in the engine bay you should have rubber on the tranny. I have always read that you should have the same material in the different mounts.

Yah I figured using different materials for the engine and trans probably wasn't a good idea so I'm glad I am not alone there. The crack is almost always in the same place one time it cracked around the last collector before the flange but almost always it was a crack in a weld in a one the pipes going down to the last collector from either the pipe running from the forward 3 cylinders collector or one of the their tubes. I can check to confirm exactly which pipe but I can assure you it is 95% of the time in the same spot. The first header I got was the traditional looking upgrade header like everyone else's and that one went like 3 1/2 years before it cracked and then the next one after that and l the others since then have been their new crazy design with pipes running everywhere.
 
I had the flex pipe installed at a local exhaust shop and I told the guy what I was trying to do and he suggested to put it in after where it crosses over.


I think if you get it removed from there and put in where the down pipe crosses from the drivers side to the passenger side that will take care of it. If you think about it when the engine revs up it's twisting side to side and not moving from front to back, so what's causing the cracking is the stiffness from crossing side to side. Alot of the reason that exhaust systems that run straight back without crossing over don't have problems like these. I also agree that if you've got rubber mounts in the engine mounts then you need to have rubber on the tranny.
 
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