Exhaust Manifold Stud Problem

[Darren_S15]

OK so Im going to be removing my turbo this weekend to fit braided hoses.

Earlier this evening I removed the nuts off my manifold after they had soaked in WD40 for over a day.

Two of the studs have come out with them though.

Now this is the weird bit, both stud have different threads on them and one of them was covered in metal like it had removed it from the block .

Also I cannot get the nuts off even with locking two nuts onto the other end, although Im hoping I should be able to fix this tommrow.

I wondered what people would do about the studs becasue even if I get a new one from Nissan Im worried I could make any damage in the block even worse?

My plan is to get the two nuts off the studs and then reuse the same studs with locking agent, but replace all the nuts with new brass ones.

Any help or advise would be great.

Thanks

 

[S15_Spec_R]

Let me know how you get on as I'm putting a ss manifold on along with a turbo elbow, braided hoses and a ths downpipe.

 

[Paddy]

Darren, I wouldn't worry about trying to take the nuts off the studs. If there that tight, treat them like a bolt instead and re-use them. Also, the studs coming out is sorta normal too.
A possibility is that the manifold had been off before and it was treadded when that stud was put back in... thats probably why you've metal on that stud. Personally, I wouldn't replace that stud. The block would probably be treadded too, so not much point. Try and refit the old stud to the block properly yourself, it might fix itself if you get it on the right tread.

Why are you replacing all the nuts? I'd be more concerned with changing the studs, if i was to replace anything because they're more likely to break.

Btw, what locking agent are you gonna use. most melt at high temperatures. heat is how you get most lock compounds off.

 

[Darren_S15]

The locking agent is Loctite Stud 'N Bearing Fit, although it doesn't say it's for high temperatures.

I'm replacing the nuts because they look tired.

I didn't think I would need to replace the studs particularly.

I need to get the original nuts off to replace these as I don't want to re-use them.

 

[Paddy]

The locking agent is Loctite Stud 'N Bearing Fit, although it doesn't say it's for high temperatures.

I'm replacing the nuts because they look tired.

I didn't think I would need to replace the studs particularly.

I need to get the original nuts off to replace these as I don't want to re-use them.

Hmmm. read the back of the loctite for temperature info. when i did the tubby bolts i used loctite high temperature stuff, but i think that stuff returns to liquid at about 230 degrees C. I didnt care, so i used it anyway, it can only help after all.

The studs take more load than the nuts. If there is a weak point, the studs are most likely to break/stretch. even if the nuts look crap, they're probably much much stronger than your new ones, they're probably hardened by the heat of the manifold.

What metal are your new nuts made from, are they nissan parts?

Be careful when your putting the manifold back on. by all means tighten the studs and nuts properly. but dont over tighten them or the studs may snap. I know there are a few s14s going around with only 6/7 manifold bolts.

 

[Nicely]

Sound like one of the studs previously sheared and was heli-coiled.

I wouldn't fit copper nuts to the manifold :no: They have to be done up tight and copper nuts will round too easily. They're perfect for the turbo and elbow though.

Locktite will be pointless. It'll burn off in under five minutes...

 

[Darren_S15]

It does not look like its been helicoiled, but then ive nerver seen anything knowing it has been.

The nuts from the manifold look to be in good condition in the threads so would it be OK to use these again?

Nicley, what would you suggest I use if not loctight?

It does say its for manifolds, but does not specify exhaust manifolds.

Would it be OK to just put the studs back in once I have the nuts off?

Thanks

 

[S15_Spec_R]

I'm curious what bonding agent you would use, I assumed that the gasket and a well tightened sections would suffice.

 

[Nicely]

You don't need any bonding agent. You'd be hard pressed to find something which could withstand temperatures up to 500[FONT=Verdana, sans-serif]ºC[/FONT]. You have to remember that the metal expansion provided by the heat is going to hold the studs solid once they are initially tightened.

 

[Darren_S15]

Thanks Nicley.

Ive just finished putting my car back together.

I did not bother to use any bonding agent in the end and was very careful not to over tighten the studs that came out.

I took the studs to a guy who builds race motorbikes to see if he could get the nuts off for me but he reckons the threads had waelded inside the nuts so I just had to use a washer instead.

Cheers for the help guys :thumbs: