Hey guys. I've read a couple threads on people having this problem, but those threads focus mostly on the turbo flange which isn't where I'm having the issue. My manifold nuts slowly back off from the studs on the cylinder head and have to be re-tightened every so often (still trying to dial in just how frequently is needed).

I actually didn't notice this until last week when I realized I had completely lost one of my manifold nuts up by the front of the engine by cylinder #4, which caused a small exhaust leak. I went ahead and replaced that one along with some others with some left over B-series nuts I had. The old B series nuts have slits/cuts in them that I think will respond better to heat expansion and may not back off quite as easily.

Has anyone else experienced this? I drive my car every day so it's a bit tedious to constantly be checking my bolts (I think I'll probably have to re-tighten them every week or so). I don't know if there's any sort of aftermarket stud/nut kit that I could use that would be better, or some sort of washer, etc....

Let me know if anyone has any ideas!

Also sidebar, my flex section was welded in at the end of my downpipe, prior to the midpipe where my O2 sensors are. I've noticed that a lot of other S2000s tend to have the flex section further back in the exhaust. Would this have any major impact on vibration? I feel like where I have my flex section should be appropriate but I'm just trying to eliminate anything that could be causing these nuts to back out.

My downpipe/flex:

Attachment 175109

 

I had the same problem when I had the pfab log manifold. I had manifold and head nuts backing off all the time. I ditched that manifold and went with the pfab eltm. I use studs and nuts with lock washer on the manifold now. For the head stud. I upgraded to the apr stud. But I use the one for the srt4 which extended out a little more so I'm able to use the washer with it. I did use some red lock tite on the inside of the head and on the outside on the nuts screwing in. So far 1000 miles and no more problem and headache on that.

 

Same thing happened to me, some red Loctite solved that problem. Guess it's a common occurrence.

 

ARP studs, Nordlock washers, OEM nuts. That's the combo that finally worked for me

 

Thanks everyone, looks like some good solutions

S2K-F8, did you use the SRT4 ARP studs like Hershey did? I'm not sure if I'll be able to get the washers on the OEM studs, although I'd like to avoid having to take off my manifold and all that shit again if possible. Also, I'm assuming 12mm Nordlock wedge washers are what I'm looking for since the nut is 12mm, already placed the order but just want to make sure because I'm feeling a bit slow right now lol...


Edit: Changed a question


Thanks again for the advice everyone

 

I had the same issue. Lock washers on both ends solved my problem.

 

Were you able to use the OEM studs?


Most people ugprading to the ARP exhaust studs seem to have used the 1.75 length ones, I just want to know if that's necessary and if so I'm a bit concerned that the 1.75 studs may run into my manifold. I have no idea if that'd be an issue, haven't even really looked at it yet, but I'm just used to absolutely everything on the exhaust side of these cards being a PITA to access.

 

Yea all oem

 

If going ARP studs you will need slightly longer ones. Stock are 1.5" iirc, so I went with 1.75" ARP studs