Exhaust manifold stud theory
03-17-2005, 01:42 PM
#1
Exhaust manifold stud theory
I installed a warpspeed y-pipe last week. As I was putting everything back together (it fit great) I was noticing there was a clamp around the pipe that attached it rigidly to the frame. This clamp is located inside the shield just past the first bend and is the only shield that can be reused. I'm thinking if this clamp is ahead if the flex section, where can the pipe move? My theory is that if the engine is revved up and the clutch is released quick and engine rocks some in it's mounts (maybe a lot with bad mounts) that the clamp holds the y-pipe before the flex section can absorb the movement. That's when the studs break.
Wiking offered the theory that if you add a y-pipe you next get broken studs. Sounds logical, but a lot of people reported back that they had stock y-pipes and still had broken studs. My theory is that you get broken studs more often if you like to pop the clutch with a 5-speed and that clamp is on tight.
I first put that clamp back on when I put on the new y-pipe. After thinking about it I took it back off. It doesn't need to be there to support anything and it may keep the flex section from being effective. Whaddayathink?
Wiking offered the theory that if you add a y-pipe you next get broken studs. Sounds logical, but a lot of people reported back that they had stock y-pipes and still had broken studs. My theory is that you get broken studs more often if you like to pop the clutch with a 5-speed and that clamp is on tight.
I first put that clamp back on when I put on the new y-pipe. After thinking about it I took it back off. It doesn't need to be there to support anything and it may keep the flex section from being effective. Whaddayathink?
03-17-2005, 01:47 PM
#2
Originally Posted by bhunter
I installed a warpspeed y-pipe last week. As I was putting everything back together (it fit great) I was noticing there was a clamp around the pipe that attached it rigidly to the frame. This clamp is located inside the shield just past the first bend and is the only shield that can be reused. I'm thinking if this clamp is ahead if the flex section, where can the pipe move? My theory is that if the engine is revved up and the clutch is released quick and engine rocks some in it's mounts (maybe a lot with bad mounts) that the clamp holds the y-pipe before the flex section can absorb the movement. That's when the studs break.
Wiking offered the theory that if you add a y-pipe you next get broken studs. Sounds logical, but a lot of people reported back that they had stock y-pipes and still had broken studs. My theory is that you get broken studs more often if you like to pop the clutch with a 5-speed and that clamp is on tight.
I first put that clamp back on when I put on the new y-pipe. After thinking about it I took it back off. It doesn't need to be there to support anything and it may keep the flex section from being effective. Whaddayathink?
Wiking offered the theory that if you add a y-pipe you next get broken studs. Sounds logical, but a lot of people reported back that they had stock y-pipes and still had broken studs. My theory is that you get broken studs more often if you like to pop the clutch with a 5-speed and that clamp is on tight.
I first put that clamp back on when I put on the new y-pipe. After thinking about it I took it back off. It doesn't need to be there to support anything and it may keep the flex section from being effective. Whaddayathink?
in theory there should be some flex in the pipe due to heat expansion. if you clamp it very tight then the pipe will need to expand else where. that usually ends up at the studs on the end of the manifolds.
IMO the studs at the heads are broken more due to age.
well when do we usually buy performance y pipes? when the car is old or when the stock one is blown up. well w/ that age on the studs (in the heads) some hammering and twisting from R&R of the pipe and the shock will probably snap a stud or two.
03-17-2005, 01:51 PM
#3
the theory sounds good and i understadn what your saying but what about autos i had a gxe that had a bunch of broken studs i replaced the rear one and then when i put on my wsp ypipe i noticed that more broke in the front
i now have a ve 5spd and there are no broken studs and there is 140xxx on the clock
my theory is they just break there are probably many variables that could cause them to break
i now have a ve 5spd and there are no broken studs and there is 140xxx on the clock
my theory is they just break there are probably many variables that could cause them to break
03-17-2005, 02:06 PM
#5
I have a theory. After changing several broken studs on different cars, I have discovered that the exhaust manifold is ALWAYS warped. Now the sixty-four dollar question:
Did the manifold warp and break the stud, or did the broken stud allow the manifold to move around and warp?
Did the manifold warp and break the stud, or did the broken stud allow the manifold to move around and warp?
03-17-2005, 02:17 PM
#7
Senior Member
iTrader: (1)
Join Date: Jan 2002
Location: Miami, FL. / Indianapolis, IN.
Posts: 2,614
do u any of u guys have pics of how u have ur WSP y-pipe installed??? i installed mine about 3 weeks ago and i used the new clamp they sent me but i don't know if i installed it in the correct area??? so if u guys can show me i will correct it if i have to once i do my engine swap.
03-17-2005, 03:41 PM
#8
my theory:
the studs are holding the manifolds on and from there the y-pipe is bolted to the manifolds. when the engine shifts, the whole y-pipe moves and pivots on the flex section. the movement of the y-pipe is only supported by the bolts from the y-pipe to the manifold and the studs. i am almost positive that if you, for instance, welded a bracket to the y-pipe (both ends near the manifold) and bolted that bracket directly to the engine to take stress off of the studs, the breakage would be cut down a lot or to even no breakages at all.
reason i think this is because i have the turbo studs (because i have the turbo engine) and i still broke some. reason is because the studs have basically be supporting the whole exhaust before the flex section (i didn't think to support the downpipe at all, gotta learn from my mistakes though).
i think that is probably the biggest reason as to why they break.
the studs are holding the manifolds on and from there the y-pipe is bolted to the manifolds. when the engine shifts, the whole y-pipe moves and pivots on the flex section. the movement of the y-pipe is only supported by the bolts from the y-pipe to the manifold and the studs. i am almost positive that if you, for instance, welded a bracket to the y-pipe (both ends near the manifold) and bolted that bracket directly to the engine to take stress off of the studs, the breakage would be cut down a lot or to even no breakages at all.
reason i think this is because i have the turbo studs (because i have the turbo engine) and i still broke some. reason is because the studs have basically be supporting the whole exhaust before the flex section (i didn't think to support the downpipe at all, gotta learn from my mistakes though).
i think that is probably the biggest reason as to why they break.
03-17-2005, 04:18 PM
#11
Reason why they break. Exhaust manifold expands when they get hot. Pushes on stud. Do this enough times and the stud will break. ie.. bend a wire enough times.
Thus needing strong studs. I've never had one break using the turbo studs.
Thus needing strong studs. I've never had one break using the turbo studs.
03-17-2005, 05:18 PM
#13
Originally Posted by GRNMAXDMON
do u any of u guys have pics of how u have ur WSP y-pipe installed??? i installed mine about 3 weeks ago and i used the new clamp they sent me but i don't know if i installed it in the correct area??? so if u guys can show me i will correct it if i have to once i do my engine swap.
03-17-2005, 07:53 PM
#15
Originally Posted by mtcookson
my theory:
the studs are holding the manifolds on and from there the y-pipe is bolted to the manifolds. when the engine shifts, the whole y-pipe moves and pivots on the flex section. the movement of the y-pipe is only supported by the bolts from the y-pipe to the manifold and the studs. i am almost positive that if you, for instance, welded a bracket to the y-pipe (both ends near the manifold) and bolted that bracket directly to the engine to take stress off of the studs, the breakage would be cut down a lot or to even no breakages at all.
reason i think this is because i have the turbo studs (because i have the turbo engine) and i still broke some. reason is because the studs have basically be supporting the whole exhaust before the flex section (i didn't think to support the downpipe at all, gotta learn from my mistakes though).
i think that is probably the biggest reason as to why they break.
the studs are holding the manifolds on and from there the y-pipe is bolted to the manifolds. when the engine shifts, the whole y-pipe moves and pivots on the flex section. the movement of the y-pipe is only supported by the bolts from the y-pipe to the manifold and the studs. i am almost positive that if you, for instance, welded a bracket to the y-pipe (both ends near the manifold) and bolted that bracket directly to the engine to take stress off of the studs, the breakage would be cut down a lot or to even no breakages at all.
reason i think this is because i have the turbo studs (because i have the turbo engine) and i still broke some. reason is because the studs have basically be supporting the whole exhaust before the flex section (i didn't think to support the downpipe at all, gotta learn from my mistakes though).
i think that is probably the biggest reason as to why they break.
03-18-2005, 12:43 AM
#19
Senior Member
Join Date: Dec 2004
Location: EU Scandinavia
Posts: 4,323
Originally Posted by oldngivout
I have a theory. After changing several broken studs on different cars, I have discovered that the exhaust manifold is ALWAYS warped. ....
I've been thinking this since, and I suppose we have the answers on this thread, multiple.
I figure the MAIN reasons are inside jeff & oldngivout answers:
- uneven heat expansion.
- Plus old bad quality studs,
- plus ypipe rigidity (stock & afterm)
- plus hard driving.
--Hard driving is divided to --sudden engine shake and --hot/cold variations...
Now my question to oldngivout is: how/which way it becomes warped? If this is known, taking heat shield wisely/properly off will counterbalance the heating = stress stays even for all bolts (not in the ends) and no broken studs.
03-18-2005, 06:27 AM
#20
Originally Posted by DanNY
dude...you can NOT weld a bracket and bolt it to the engine. the heat expansion of the exhaust pipe will either break your bracket or break something else. you need to bolt it to something that has some flex in it.
03-18-2005, 07:17 AM
#22
Guys, just call your dealer and tell them you need the studs for the Maxima.. they have superseeded the old part number with the turbo studs.. so when you order ones for a Maxima, you get the turbo studs.
As for this clamp you're talking about, that clamp holds the Y pipe to the engine, NOT the frame. look at where the bracket and think about things for a while.
that bracket is made of soft, thin steel and is attached to the tranny bellhousing. this holds the Y pipe more rigidly to the engine/tranny to PREVENT stress on the studs, not increase it!
The rest of you jumping on that bandwagon should pull your heads out of your butts before listening to blather like this and following their conclusion.. HELLOOOOO! Nissan wouldn't be stupid enough to clamp the exhaust to the frame dirctly below the engine.
[/rant]
As for this clamp you're talking about, that clamp holds the Y pipe to the engine, NOT the frame. look at where the bracket and think about things for a while.
that bracket is made of soft, thin steel and is attached to the tranny bellhousing. this holds the Y pipe more rigidly to the engine/tranny to PREVENT stress on the studs, not increase it!
The rest of you jumping on that bandwagon should pull your heads out of your butts before listening to blather like this and following their conclusion.. HELLOOOOO! Nissan wouldn't be stupid enough to clamp the exhaust to the frame dirctly below the engine.
[/rant]
03-18-2005, 08:03 AM
#23
Originally Posted by Matt93SE
The rest of you jumping on that bandwagon should pull your heads out of your butts before listening to blather like this and following their conclusion.. HELLOOOOO! Nissan wouldn't be stupid enough to clamp the exhaust to the frame dirctly below the engine.
[/rant]
[/rant]
03-18-2005, 09:39 AM
#25
They use the same size studs in ALL of the VGs out there. the Z31 never had a huge problem with them breaking, but for some reason the Maxima did.. sure the turbo studs are a bit harder, but they're still the same size, length, and thread pitch. nothing changed but the materials.
doesn't make sense to me either, but people are getting all worked up about the wrong issues on these cars. realize where the problem is coming from and fix it, don't sit there and b!tch about everything known to man when we already know what the problem is.
doesn't make sense to me either, but people are getting all worked up about the wrong issues on these cars. realize where the problem is coming from and fix it, don't sit there and b!tch about everything known to man when we already know what the problem is.
03-18-2005, 09:47 AM
#27
Originally Posted by Matt93SE
They use the same size studs in ALL of the VGs out there. the Z31 never had a huge problem with them breaking, but for some reason the Maxima did.. sure the turbo studs are a bit harder, but they're still the same size, length, and thread pitch. nothing changed but the materials.
doesn't make sense to me either, but people are getting all worked up about the wrong issues on these cars. realize where the problem is coming from and fix it, don't sit there and b!tch about everything known to man when we already know what the problem is.
doesn't make sense to me either, but people are getting all worked up about the wrong issues on these cars. realize where the problem is coming from and fix it, don't sit there and b!tch about everything known to man when we already know what the problem is.
03-18-2005, 11:14 AM
#28
Originally Posted by Matt93SE
Guys, just call your dealer and tell them you need the studs for the Maxima.. they have superseeded the old part number with the turbo studs.. so when you order ones for a Maxima, you get the turbo studs.
As for this clamp you're talking about, that clamp holds the Y pipe to the engine, NOT the frame. look at where the bracket and think about things for a while.
that bracket is made of soft, thin steel and is attached to the tranny bellhousing. this holds the Y pipe more rigidly to the engine/tranny to PREVENT stress on the studs, not increase it!
The rest of you jumping on that bandwagon should pull your heads out of your butts before listening to blather like this and following their conclusion.. HELLOOOOO! Nissan wouldn't be stupid enough to clamp the exhaust to the frame dirctly below the engine.
[/rant]
As for this clamp you're talking about, that clamp holds the Y pipe to the engine, NOT the frame. look at where the bracket and think about things for a while.
that bracket is made of soft, thin steel and is attached to the tranny bellhousing. this holds the Y pipe more rigidly to the engine/tranny to PREVENT stress on the studs, not increase it!
The rest of you jumping on that bandwagon should pull your heads out of your butts before listening to blather like this and following their conclusion.. HELLOOOOO! Nissan wouldn't be stupid enough to clamp the exhaust to the frame dirctly below the engine.
[/rant]
My theory shot to hell---that's what theories are for-- to make people think. This time mine was wrong.
03-18-2005, 12:03 PM
#34
Senior Member
Join Date: Dec 2004
Location: EU Scandinavia
Posts: 4,323
The stress that Y-pipe exerts on both manifolds as tightened cold, maybe grows worse when hot.
That stress may be be relieved by heating either pipe red hot after engine exhaust manifolds has been driven hot also.
Will it solve anythin, dunno.
That stress may be be relieved by heating either pipe red hot after engine exhaust manifolds has been driven hot also.
Will it solve anythin, dunno.
03-18-2005, 12:25 PM
#35
Senior Member
Join Date: Mar 2002
Location: Ontario, Canada
Posts: 1,114
Y pipe is not enough rigid to cause so much damage by thermal expansion of the left and right sides of Y, plus tilting of the engine is much more stressful. The thermal expansion of the manifolds, combined with improper material of the studs is the key. Should they have made the studs of right steel there would not have been a problem.
03-18-2005, 01:20 PM
#36
Originally Posted by Tarzan
Y pipe is not enough rigid to cause so much damage by thermal expansion of the left and right sides of Y, plus tilting of the engine is much more stressful. The thermal expansion of the manifolds, combined with improper material of the studs is the key. Should they have made the studs of right steel there would not have been a problem.
03-18-2005, 01:27 PM
#37
I very much doubt that Eric. The Y is mounted to some very sturdy manifolds. It's the expansion/contraction of the iron flanges on alumin heads that break the studs IMHO.
But you are right about flex. If it's too short, it won't flex enough and the accordian section inside will crack and then leak (causing noise and a loss of torque/hp).
Here was my solution: 2nd pic, you can see the old short flex cut out. I welded in a new longer flex and a shorter 4-gen hi flow cat.
http://community.webshots.com/album/130755966JCNcyY
But you are right about flex. If it's too short, it won't flex enough and the accordian section inside will crack and then leak (causing noise and a loss of torque/hp).
Here was my solution: 2nd pic, you can see the old short flex cut out. I welded in a new longer flex and a shorter 4-gen hi flow cat.
http://community.webshots.com/album/130755966JCNcyY
Originally Posted by eric93SE
I'm sure my Warpseed Y will be the cause of my exhaust manifold studs failing (combined with bad engine mounts). I have a 'flex section' that DOES NOT FLEX, POS.
03-18-2005, 02:16 PM
#38
Regardless, I have a Y that does not flex, now when the engine bucks a little (from going WOT, or driving it hard) the Y cannot flex, so the stress (applied torque) from the weight of the ENTIRE exhaust system is on the manifold.
Your solution looks good Jeff, but not everyone has welding facilities.
Your solution looks good Jeff, but not everyone has welding facilities.
03-18-2005, 02:28 PM
#39
I've had 2-3 short flex sections with my Cattman. In all situations, it was the accordian lining that broke inside, not the studs. So after spending alot of $ getting the short/stiff flex sections put on and having them break yet again, I just bought a cheapo welder and fixed the problem myself. Well I bought the welder for other reasons 
but it paid for itself with this one project alone.
Short flex. It would fail within months of getting it fixed. My fix. Has worked flawlessly for over a year and the flex's mesh shows no carbon desposits indicating a leak of any sort so far.
but it paid for itself with this one project alone. Short flex. It would fail within months of getting it fixed. My fix. Has worked flawlessly for over a year and the flex's mesh shows no carbon desposits indicating a leak of any sort so far.
Originally Posted by eric93SE
Regardless, I have a Y that does not flex, now when the engine bucks a little (from going WOT, or driving it hard) the Y cannot flex, so the stress (applied torque) from the weight of the ENTIRE exhaust system is on the manifold.
Your solution looks good Jeff, but not everyone has welding facilities.
Your solution looks good Jeff, but not everyone has welding facilities.
03-18-2005, 03:58 PM
#40
Eric, if your flex isn't moving, then you have the bolts on too tight. Many car manufacturers have been using those types of joints for DECADES and they work fine.
In fact, there are two of those joints on the stock exhaust of the Integra sitting in my driveway.
In fact, there are two of those joints on the stock exhaust of the Integra sitting in my driveway.