8Gomer9

Here it is guys, my setup is a boosted B18c1 setup, my issue that i am running into lately is that, it seems the exhaust manifold studs are starting to break frequently at this time.

A little history: The first 3 exhaust manifold studs broke off at the same time, all of them on the left side of the head, if your facing it. I had those 3 fixed, but it was fixed by having the rest of the stud taken out and replaced with a hex-bolt (m8 x 125 i believe). The bolts held up for a few months, then all 3 of them snapped off, they snapped off behind the manifold in the head. 2 of the 3 bolt pieces were loose, so i could get them out, the third was drilled out, and they were all 3 replaced with bolts once again. At the time the 3 bolts were replaced again, a 4th exhaust manifold stud snapped out from the head while threading the nut on. Just yesterday 1 of the 3 bolts backed out, and could not be put back in, it seems the threading is stripped inside the head, and this is the bolt that is all the way to the left on the manifold at the end so it is allowing separation and leading to a bad exhaust leak.

I am having a separate issue as well that could have a possibility of contributing to the snapping of the exhaust manifold studs, but im not completely sold on it. When i am just cruising in my car and i approach 70 mph in 5th gear, my car seems to start to shake until i get to high 70's or 80 mph. The shaking does not happen if im doing a pull through that range in MPH, only when i am cruising, and the shaking does NOT happen at any other time, no other MPH range or any RPM range. What do you guys think could be the matter? and could that be contributing to stress on the manifold studs causing them to weaken and eventually snap?

My main questions i am looking for to be helped out with are:
Should i / can i have new exhaust manifold studs put back in the head? or

Should i have all the exhaust manifold studs removed and replaced with another certain kind of bolt that won't back out? since they all seem to be snapping off. or

Is there a different option i am not considering that would be superior to all?

Regarding the shaking issue:
What do you guys think could be the matter? and

Could that be contributing to stress on the manifold studs causing them to weaken and eventually snap?

If any other information is needed from me please just ask, and I thank everyone for helping me out in advance, these are my only 2 problems with my car and are really keeping me from enjoying my set up. Thanks again fellas!

honda.lioness

Are you using metric Grade 10.9 bolts for the exhaust manifold? Try to get studs of the right length, and use self-locking nuts (as required by the shop manual). From http://www.hondapartsunlimited.com/, the studs should be 8 mm nominal diameter (like you wrote) and 37 mm long. My manuals for my Civics suggest the 1.25 mm pitch you mention is right. When installing the studs in the head, use the double nut technique and apply 23 ft-lbs. of torque (from my shop manual).

The exhaust manifold studs commonly fail on c. 1990s Civics. One of my 91 Civic's spontaneously broke while I was doing a suspension renovation (hence a lot of banging and so vibrations) in 2006. I replaced all of mine on my 91 Civic in 2006, using studs I bought from my local import shop. They were still fine when I sold the car in early 2009.

Have your wheels been balanced recently? A shimmy at certain speeds like you describe could trace simply to an unbalanced wheel.

8Gomer9

thanks for the great info, i hadn't had my wheels balanced since i had the new tires put on a little while back, and never really considered that since i hadn't rotated the tires or anything, Would i simply have to get the wheels balanced in your opinion? or should i do a front end alignment while i am at it? thanks again for the great info!

honda.lioness

Has it been awhile since you had an alignment? Are there signs the car does not, for one, drive straight? E.g. drive along somewhere where there is little to no traffic, and release your grip on the steering wheel. Does the car drift right or left? Also, at high speeds, do you have to apply force to keep the car driving straight? If it has been awhile since an alignment or the car is not driving straight, then yes, get the wheels balanced and have the front end alignment done. This may not fix the shimmy (but it might!).

Also, are you rotating the tires every 5k miles? Some prefer 7.5k miles. Go with what your owner's manual says.

Another possible cause of the vibration is a loose or corroded engine mount. This is pretty common on older Civics.

strategy400

Are all the support brackets in place on the exhaust manifold and remaining system? Are you using a torque wrench?

8Gomer9

honda.lioness- yes it has been roughly a year since i had an alignment, maybe take a couple of months. The car doesn't drift left or right when i release the wheel, and just normal grip at higher speeds except the 70 to 80 range, but i obviously stay below or above this range depending where im at. haha. I do rotate right around the 7K mark. I thought about the engine mounts possibility, the mounts I had used were Avid mounts when the swap was performed, i will take a closer and in depth look at this.

strategy400- i do believe all supporting brackets are in place, although i did not use a torque wrench when i replaced the last 3 bolts myself, but the first time they were replaced i am assuming one was used because it was done by a shop, but then again skeptical because when they broke off behind the manifold in the head, there was a little sticking out and were loose and got them out with minimal effort when i pulled the manifold off a little bit, it seemed there would be very limited space, i tried my best to torque by hand when i did the last 3, 2 have remained perfectly fine, and when the 4th stud broke while replacing the 3 bolts last time, i put maybe one turn on the nut when it got up to the manifold, and the stud just gave out.

Thanks for the help and input guys.

strategy400

Helms says 23 ft. lb. tighten in a crisscross from the center in 2 or 3 steps (for the D series engines I'm looking at). One of the reasons for proper torquing includes not overstressing the fasteners. There is a support bracket on my exhaust manifold that connects the bottom flange to the bottom edge of the block. A bouncy car will need all these things correct. Shaking at a certain speed would suggest a bent rim, bad tire, badly balanced tire, mud in the rim or something to do with your wheels. My car was wobbling at a certain speed (80?) because one of my rims/tires was bad. I bought new rims and tires and it rolls smooth now at all speeds.

You'll probably have to helicoil the stripped stud 'eh?

I did hear of a liquid thread repair that has been getting good reviews. it consists of an epoxy you fill the hole with, a release agent you put on the bolt/stud and then you screw it in and let it dry. Unscrew it and your good to go. In the case of your stud you might not even have to unscrew it. The hole probably has to be super clean though, like with solvent and compressed air.

I'm considering this for my Toyota pickup that has a stripped camshaft bearing cap bolt hole.

http://www.permatex.com/documents/td...tive/81668.pdf

honda.lioness

Then I personally would skip the alignment for now; see if any of the wheels prove to be unbalanced; and if they are, balance them. (I am sure you know this; just keeping us on the same page here.)

Corksil

if it were my car, I would unbolt the header and remove the studs, see if there is any torque on the header to the left or right, this could happen with worn exhaust mounts or something of the sort. if the header is applying lateral forces to the engine, this could explain the bolts shearing off. if everything is lined up as it should be, then I would proceed as follows....

remove all bolts, use a tap-die to widen up the holes and put new threads into the head. replace the header gasket with a hondata one to keep temps from leaching into the head and soiling your intake temperatures.

after you have new holes in the head, use high-temp ARP bolts to bolt the header on with red (permanent - sweeter than blue) locktite and then torque the **** outta them - read the manual, then exceed slightly.

this should keep your header where it belongs.

best of luck, post up the things you have tried if they keep breaking. and remember - insanity is trying the same thing again and again and expecting a different result. mix it up a bit...

Jackal6042

Yeah you should be good on alignment if it doesn't pull... My suggestion on the shake thing is check the tie rod ends and ball joints... Those are usually a culprit for stuff like this.

As far as the studs goes... I wouldn't recommend using bolts, if you **** up the threads in the head your options for repairing it aren't the best (helicoil or liquid thread repair not as strong as metal). ARP makes some replacement studs, but first diagnose why they are breaking. Check for a worn or torn engine mount that could be causing lateral movement of the engine.

Dokta

Actually a helicoil or threaded insert would be much stronger than a tapped hole in aluminum.

Do not use bolts. Using studs in this application are important because while torquing down on the nuts, the studs don't move. The only force being applied to them is the twisting force that goes through the nut, which gets changed to an axial force through the threads and pulls the stud stretching it appropriately. Therefore the stud only experiences the axial force pulling them out. A bolt experiences both a twisting force and the axial force when you are torquing them. This unnecessarily stresses the fastener during installation.

Make sure you are using the appropriate grade hardware. ISO 898 gives the properties of different materials for metric fasteners. An ISO property class of 8.8 means the minimum nominal tensile ultimate strength is 800 MPa and the minimum nominal tensile yield strength is 0.8 or 80% of the tensile ultimate strength, or 0.8 * 800 = 640 MPa. If you are having problems with breaking bolts, I would go with a grade 10.9 in this application.

Self locking nuts are a must because of the large temperature range and the constant vibrations experienced there. But please do not use the nylon type. They will simply melt out. Either use the OE nuts from the Honda dealership, or find a good serrated flange nut from a reputable supplier.

Last but certainly not least, make sure you use a torque wrench that is in the proper calibration. When torquing the nuts, be sure to follow the appropriate torquing sequence. Start off hand tight on each nut through the sequence, then about 12 ft-lbs over each of them in the same sequence, then finally 23 ft-lbs. I can't remember the sequence exactly, but for long flanges like the exhaust manifold, you always start at the center and work your way out when tightening.

When the correct fasteners are installed properly, they should be able to withstand a lot of heat, vibration, and abuse.

fastrxu

Definitely check to see if your exhaust manifold has a bracket down under the block to secure it from moving around.

Maybe a hondata INTAKE manifold gasket would help by lowering intake temps (i think it actually lowers intake temps by like 15-20 degreea) thus lowering exhaust air temps.

Ps you dont have a flexpipe in your exhaust piping do you?
Cu that would definitelt cause unwanted movement

8Gomer9

thanks for all the help guys, i have been super busy with a new job. I am gonna check out seeing if the tires are balanced properly, and hold off on the alignment and see what happens, makes good sense, then move to the less obvious that has been pointed out, althought i have looked at a few, engine mounts seem fine, and exhaust brackets seem in place.

For the stripped hole, i was considering going the helicoil route to repair, can anybody give me the link on the liquid thread repair that gets good reviews so i can check it out?

Grade 10.9 would be the grade of bolt with the RED locktite i would make sure to use, if that is my route, instead of replacing with new studs and the oem self locking nuts.

I infact dont have a flex section in my downpipe nor in my exhaust system itself.

Hondata gaskets are a must, good call guys.

Thanks again for all the feedback and help should be making a for sure decision soon, once i get in the routine of the new job and all that good stuff, thanks again everybody!

strategy400

http://www.permatex.com/documents/td...tive/81668.pdf

It will be hard to drill/tap for helicoil I would think. If the liquid repair doesn't work you could always helicoil later.

Red locktite might be overkill unless things are backing out.

Jackal6042

True, the strength of the thread would be greater. But all in all it would still be in aluminum.

8Gomer9

ok guys, i have made the decision to Helicoil the stripped exhaust manifold stud and have all the studs replaced with the Grade 10.9 bolts.

I need some help on finding out the thread size, is it 8mm diameter?, to select the right Helicoil set. Also can i grab the Grade 10.9 bolts at say an autozone? or where?

Links would be great for both the Helicoil set and Grade 10.9 bolts to be used, thanks fellas, almost out of the water on this just need a little more help, thanks again!

GSaura

What I use are replacement studs from the factory with antiseize that are tightened to what feels like the correct torque. It's almost impossible to get a torque wrench on a turbo manifold nut, so torquing is likely not your problem.

If you're using a cheap manifold, the expansion of the manifold may be leading to shearing of whatever hardware you're using.

Mcmaster carr online has pretty much every piece of hardware you'll ever need if you don't want to use OEM hardware. Locally for me, Ace hardware is where I go. Autozone won't have anthing remotely close to what you need probabl.

8Gomer9

i do agree it is damn near impossible to get the torque wrench in there.

i definitely dont believe it to be the manifold because it has been a great reliable one for roughly the past 2 years.

As i look around i came across the ARP exhaust manifold stud kit running about $125 and has sparked my interest to replace all the manifold studs with this kit, any opinions?

Around my way locally i would relate to a True Value Hardware, i will check it out. thanks for the input man, its appreciated.

san_luis

Hi:
The same happen to me. Trying to replace Oxigen Sensor, decided to remove whole exhaust manifold assembly. I got now 2 stud bolts broken inside of cylider head (the left on low row and the right on low row).

any suggestion to remove them.

regards

spchyperwarp

im having a major issue. my car i have now has 602hp @18psi and the arp studs keep snapping any suggestions on how to fix this problem? send answers to hyperwarp2@yahoo.com

integraty95

iTrader: (1)

That's what this whole threads about if you read it. back on topic.

Don't know if you have already fixed your problem but i believe the bolt size for the exhaust manifold is 8mm x 1.25 someone correct me if I'm wrong.

ef_addict

What is the double nut technique? Putting two nuts on at the same time so they lock on each other? I need to replace a stud and this thread seems pretty helpful.

challenger63

use stage 8 locking manolifold bolts,and your front end shake is definitely a balance issue.

TomCat39

This information may prove helpful to future users but for the OP your are responding to, they may not even have that car or setup anymore.

I think you may have missed that that was 8 years ago the OP posted that issue.