J-pipe failure...AGAIN

[wareaglescott]

Had an exhaust leak on my Coyote powered car. Upon investigation I realized the J-pipe was fractured. This is the 2nd time this has occurred. After the first time I made some supports I documented in my build thread to help support the weight up by the J-pipe. Those seemed to help a bunch as the first failure was within the first 1000 miles I think.

Also since the first incident I have added the flow master slimline mufflers to the sidepipes which I love but are quite a bit heavier than the stock side pipes. At this point my only complaint about the car 5700 miles in is the header/J-pipe?side pipe combo. IF I could do it again from scratch I absolutely would have done 4 into 4 headers and eliminate the J-pipe from the setup. I don't think the J-pipes are structurally strong enough for long term use with the added weight of the mufflers.

I am considering making a change. Has anyone successfully removed and replaced a shorty header/J-pipe combo for a 4 into 4 full length header in an MK4 without lifting the motor out of position? Not sure if it is possible to get the header off and the new one on particularly on the drivers side.

Now I am aware of the potential performance increases associated with the other header option. That is not really my concern. They way I drive the car I have never felt I needed more power so I don't care about that. I just want reliability but I don't want to take the motor out to swap headers.

[cgundermann]

Sorry to hear about that Scott. Pretty big motor to work around - wish you luck my friend.

Chris

[wareaglescott]

Thanks Chris

[Papa]

Scott,

I know what a pain in the back side it is to install headers; installed four sets on my car before I had what I was happy with. If you want to do it one more time, consider the vendor I used. With your lift, you should be able to go in from the bottom for header bolt access. Here is a picture of their Coyote header with double collector:



Dave

[wareaglescott]

Thanks Dave. Still looking for the answer to the question if anyone has taken the headers off with the motor in the car in a coyote/MK4 combination?
I have no doubt the other option would be a better end result. Just not sure if it is worth the cost and hassle.
I struggle to even get a wrench on the bolts on the drivers side with the car on the lift from underneath.

Would love to hear anyones experience of getting the headers on and off.

[mike223]

I don't want to take the motor out to swap headers.

Not a Coyote - so only SBF conjecture on my part.

But key to my thinking is that the 4 into 4 headers have to go on the engine after engine installation / the 4 into 4 headers have to come off before you can pull the engine / the engine will not go in or come out with 4 into 4 headers installed...


I can't imagine how that could be different for Coyote.


P.S. - And yes, it would have to be tight on the driver's side with a Coyote - but if there are Coyote 4 into 4 headers out there - someone has done it.

[wareaglescott]

Not a Coyote - so only SBF conjecture on my part.

But key to my thinking is that the 4 into 4 headers have to go on the engine after engine installation / the 4 into 4 headers have to come off before you can pull the engine / the engine will not go in or come out with 4 into 4 headers installed...


I can't imagine how that could be different for Coyote.


P.S. - And yes, it would have to be tight on the driver's side with a Coyote - but if there are Coyote 4 into 4 headers out there - someone has done it.

No offense but unless you have worked on or directly seen the space available to access the drivers side header bolts on a coyote conjecture based on a SBF is not really worth anything.
I am aware of how people get them on without the body in place which generally consists of doing it with the engine mostly in position lowered below the upper frame rails. Body on is an entirely different ballgame as far as maneuvering the header in position even if you can get to the bolts.

[mike223]

Fair enough - seems I recall someone on one of the sites that cut an access panel in the driver's footbox for that sort of issue.

Certainly several of us (most notably 2bking) did fairly extensive footbox mods in that area to improve access to 351w header bolts / sparkplugs.

I'm aware that the Coyote / mod motor (?) is a bigger problem in that area than 351w.


But I find it difficult to imagine that builders are assembling Coyote builds in a manner that requires the body to come off for header removal and engine removal... (???)

[2bking]

I think the splash panels will have to come out as well as the steering shaft but then it will be no different than the body off install. All the headed bolts can be accessed from some direction with the right tools. I got access to the ones close to the firewall from the top of the engine which would be more difficult with the body on. I left the studs in my heads and it created a little more problem that had to be solved by loosening the motor mounts for a touch more clearance. I found a ratchet end wrench was my friend for some of the fasteners. I suggest you try to get to every fastener to find how difficult it would be and then make your decision.

[Dave Howard]

I am considering making a change. Has anyone successfully removed and replaced a shorty header/J-pipe combo for a 4 into 4 full length header in an MK4 without lifting the motor out of position? Not sure if it is possible to get the header off and the new one on particularly on the drivers side.

To answer the above question....YES. My Coyote/MkIV build in 2012 initially had the same shorty headers and J-pipes. Between 1st start and go cart stages, the Stainless Header 4x1x4 became available. I purchased a set and installed them without removing the engine. In fact, there is more finger and wrench room with the 4x1x4 headers.

[wareaglescott]

Thanks King.
At this point I am drowning in budget woes on my '79 Porsche build! lol I am not doing anything until I have another failure but our emails sure had me thinking about it. The cost/hassle factor is a long way from overcoming my desire to do this although it would be quite nice I believe from a performance/ sound/ durability stand point.
Mainly I just wanted to know what it would take. I absolutely agree the steering shaft and splash panels would have to come out.
My main concern is the room to maneuver the header in and out. I imagine with the right tools the bolts could be reached. I have checked my bolts a few times for tightness since completion and struggle with 1 in particular to reach on the drivers side.

If I were to loosen the motor mounts would I be able to move the entire package slightly without unhooking the driveshaft?

[wareaglescott]

To answer the above question....YES. My Coyote/MkIV build in 2012 initially had the same shorty headers and J-pipes. Between 1st start and go cart stages, the Stainless Header 4x1x4 became available. I purchased a set and installed them without removing the engine. In fact, there is more finger and wrench room with the 4x1x4 headers.

Good to hear Dave. Yousay between first start and go cart...so I am assuming the body was not on? Is that correct?
My main concern is the ability to maneuver the header into position.

[edwardb]

I agree with King. Splash guards would be the first thing to come out. Along with the side pipes of course. Also agree with King that the issue is with a handful of header bolts on the DS. After you exercise every tool option, one other suggestion is something I did when I was doing my Coyote installation. I found that with the DS motor mount removed, access to the troublesome bolts was improved. Granted, that was when I was installing the engine and still had the shop crane attached so I could lift the engine just enough to work the mount out and then back in after the header bolts were all tightened. I realize this suggestion is a little "out there" but it worked for me.

I have the same GP Headers straight tube headers pictured in a previous post, and they're awesome. Those were the only options available when I did mine. Since then, Factory Five has Coyote straight tube headers available that are apparently decent quality a somewhat cheaper, although I haven't used them. I believe that Gas-N also sells Coyote headers for the Roadster.

[Al_C]

Scott - this is not an easy fix, but I believe it is do-able. First a question: did you use bolts to attach the headers, or studs? I put the stage 8 fasteners on mine so I have studs, and that might be a little easier solution for when you put the new headers in. I agree with King and Edwardb and offer one other idea. When I was in the very early stages, I asked a bunch of people about how to keep header bolts secure. One that I saw was BansheeKev's coyote. He put an access panel in the drivers side footbox to access the bolts. That panel made the header bolts accessible in his completed car. So, from the peanut gallery, this is what I'd do: with the car on a lift, get a jack under the engine to prop it up "a little". Take the motor mount out as Edward recommends, then you should have access. If you need more access, cut a panel out of the footbox that you can replace and secure with some sheet metal screws. In my opinion, it might be easier to install the new headers if you have studs in place. Opposing view points will most likely show up, but the studs worked on mine. With the locking fasteners, you can at least eliminate the loose header potential. You should be able to work the bolts or nuts with a crowfoot wrench.

[Ducky2009]

I used bolts on my headers. Installed headers with the engine mounts bolted in place. After installing the front couple bolts and the rear one, I slid under the car from the DS and moved until I was looking at the starter. At this point my hands could reach and turn the rest of the bolts. Couldn’t see what I was doing but could feel them.

Next question- Can you get them in. Don’t know, but I’ll be following along to see how it works out. Good luck!

[boat737]

.... With the locking fasteners, you can at least eliminate the loose header potential. You should be able to work the bolts or nuts with a crowfoot wrench.

Or a Torque Extender (my go to solution on the 351W/427.). Snap-on has them.

[wareaglescott]

AL - I used bolts. I also used the remflex gaskets. I have checked the header bolts three to four times since the car has been completed. Never any signs of them loosening so far at 5700 miles. As previously stated it is pretty miserable task just getting a wrench on them.

Ducky - I am assuming you did not have the body on when you did this? That seems to be the million dollar question on whether it can be done with the body on.

Another large concern I have is if I can in fact get them on will the outlet flange to connect to the side pipe be in the same position as mine currently are and how will the body cutout line up. My body work was done to accommodate my current setup. I sure don't want to modify the cutouts on a finished body as the edge would look horrible. There is really not a good way to figure that out other than trying it best I can tell. Paul is going to send me some pictures later of his and maybe I will be able to tell something from that.

At this point I feel my best option is to get a J-pipe made out of stronger material. The FFR ones are SS. I know nothing about different grades of steel and welding techniques on what would be better. Anyone have input on this?

[Duke]

My 2 cents: replace the Jpipe with another 'stock' one. See if it fails again. Alternatively, go to a muffler shop and have them add a second brace to the side pipes near the end/under the seat. Reduce unsprung, reduce possible future jpipe failure.

[WarDamnEagle]

Scott,

Do you have pictures of the J pipe failures, I am curious what is failing on them.

I kind of agree with duke, based on the failure area, additional exhaust hangers might be a good solution.

[phileas_fogg]

Onlinemetals has a description of the various types of steel.

Stainless: https://www.onlinemetals.com/product...nlessguide.cfm

"Regular": https://www.onlinemetals.com/product...steelguide.cfm

Cheers,


John

[wareaglescott]

Scott,

Do you have pictures of the J pipe failures, I am curious what is failing on them.

I kind of agree with duke, based on the failure area, additional exhaust hangers might be a good solution.

There are pictures in my build thread latest update and it also references the post # from the first failure and my additional supports. Build thread is linked below in my signature.

[wareaglescott]

Onlinemetals has a description of the various types of steel.

Stainless: https://www.onlinemetals.com/product...nlessguide.cfm

"Regular": https://www.onlinemetals.com/product...steelguide.cfm

Cheers,


John

Good info thanks. The FFR site just says "stainless steel" in the J-pipe description so not sure what grade they are.

[cgundermann]

Scott ~

My one penny concurrence with Duke's two cents, is continue with another new J-pipe and/or augment or custom make a beefier reinforced one. It gives me the hate shivers thinking of trying to get a four into one back in that finished gorgeous car.

Chris

[wareaglescott]

Scott ~

My one penny concurrence with Duke's two cents, is continue with another new J-pipe and/or augment or custom make a beefier reinforced one. It gives me the hate shivers thinking of trying to get a four into one back in that finished gorgeous car.

Chris

Never heard the term "hate shivers" before but I like it and it is a perfect description! haha
OF course now it is in my head that I could have better performance. Totally don't need any better performance but darn it sounds good and has the wheels turning.

[Jeff Kleiner]

...Another large concern I have is if I can in fact get them on will the outlet flange to connect to the side pipe be in the same position as mine currently are and how will the body cutout line up. My body work was done to accommodate my current setup. I sure don't want to modify the cutouts on a finished body as the edge would look horrible....

Understandable. It's virtually guaranteed that the cutouts would need to be massaged if you were to make the change but it's not as bad as it sounds. I've done it on painted cars---a couple layers of masking tape around the opening then working a little at a time using a 1 1/2" sanding drum in a pneumatic die grinder or drill removes material cleanly. After pulling the tape you'd never know that it was done after paint.

Jeff

[cgundermann]

I have the J-pipes in mine and like you, extremely happy with my current performance of my motor (347 versus Coyote). Other than bragging rights with more power to swap 4 into 1, my estimated 450 horses keeps my pretty darn honest. Mine would be much easier, but for now I'm good...

Chris

[boat737]

Just curious Scott, are you running the muffler hangers? (I looked through your thread, but couldn't find it...)

[wareaglescott]

Just curious Scott, are you running the muffler hangers? (I looked through your thread, but could find it...)

Yes

[RLKfarmboy]

Hey Scott

My reply is probably late regarding the j- pipe situation. I recently dealt with the same issue with j- pipe failures. Both of mine cracked at less than 2300 miles. I was able to remove both exhaust manifolds and replace with F5R straight tube headers without pulling the engine or removing the splash panels. The driver side offers a bit of a challenge regarding 2 of the bolts. ( Try a angle box end wrench , ratchet wrench, or a swivel head ratchet to simplify the task.) Fortunately installing the straight tube headers is straight forward and a easy installation with the increased room in the attachment points. The pax side cutout is a little different than the cutout for the j- pipe but a easy mod with a drum sander. Additionally I was required to relocate the side exhaust hanger mounts. I wrapped the headers with Cool Guard and it makes a noticeable difference in engine bay temperatures. I have a Coyote 50XS installed in my # 20 of 20th. anniversary model. Kinda like shooting a Cat 3 on a cold dark night. You will be happy with the straight tube headers.

[TexasAviator]

Scott,

The 4 into 4 headers may still crack under the strain of the heavier pipes. The guy that dyno'd and broke in my engine has 4 into 4 ceramic headers from FFR and they cracked under the twisting load on the header from the heavy pipes. He has the flowmasters like you do. You may want to get with BOBL on here and see what he has done. You may still have cracked headers but now they are going to be a much more expensive piece than the J pipes.

[wareaglescott]

Hey Scott

My reply is probably late regarding the j- pipe situation. I recently dealt with the same issue with j- pipe failures. Both of mine cracked at less than 2300 miles. I was able to remove both exhaust manifolds and replace with F5R straight tube headers without pulling the engine or removing the splash panels. The driver side offers a bit of a challenge regarding 2 of the bolts. ( Try a angle box end wrench , ratchet wrench, or a swivel head ratchet to simplify the task.) Fortunately installing the straight tube headers is straight forward and a easy installation with the increased room in the attachment points. The pax side cutout is a little different than the cutout for the j- pipe but a easy mod with a drum sander. Additionally I was required to relocate the side exhaust hanger mounts. I wrapped the headers with Cool Guard and it makes a noticeable difference in engine bay temperatures. I have a Coyote 50XS installed in my # 20 of 20th. anniversary model. Kinda like shooting a Cat 3 on a cold dark night. You will be happy with the straight tube headers.

Thanks for the information

[CraigS]

A couple of thoughts for you. 1- Could the header to j-pipe joint be made flexible like these?
https://www.napaonline.com/en/p/BK_7357321
These type joints that I have seen have the bolt w/ a long shoulder so the bolt stops turning when the spring is compressed to the point the OE engineers decided was best. You could do similar using a stud and some double nuts or maybe (although I hate them) deformed metal nuts
2- Could the pipe itself be made flexible w/ one of these?
https://www.aceraceparts.com/collect...Flex-Couplings
These flex pipe sections have been used on nearly every front wheel drive car since the 70s and are very common. Nearly any exhaust shop has them on hand (although maybe not in a large enough size for you) and can cut out the old and weld in the new in < 1 hour.
If you could incorporate either or both of these, you could work out hangers similar to what you have to fully support the weight of side pipe and tighten down it's location while still allowing the engine to move.

[wareaglescott]

interesting thoughts Craig. For now I am watching them closely and seeing how they are doing since my last failure and fix. I think you option 2 is a very viable solution. Not sure 1 would work because the end of the header is like a ball cup joint (not sure if that is the proper term) Anyways to incorporate 1 it would take such fabrication it would be easier just to get new headers and eliminate the J pipe altogether.