Andyjo Posted July 13, 2008 Share Posted July 13, 2008 Alright, so i've gotten back into the Impreza (97 OBS, 2.2L) again, and one (or more) of the header mounting studs has stripped in the block.. the studs are fine, but block isn't.... So plan of action... drill & tap / helicoil? Anyone have any better ideas? Maybe I should stop messing w/ the exhaust after i fix this one... Does anyone know where i can find a helicoil of the right size? it's some crazy metric size... and I don't feel like re-tooling (us-metric) the whole underside of the block... Link to comment Share on other sites More sharing options...
jp98 Posted July 13, 2008 Share Posted July 13, 2008 The helicoil is the way to go. Any auto parts store should have one to fit your needs. Back in the 70's I striped out one on a Volkswagen head and the kit that I picked up had the drill and coil in one package but I haven't needed to look for one for some time now. Jim Link to comment Share on other sites More sharing options...
idosubaru Posted July 13, 2008 Share Posted July 13, 2008 hey andyjo, good to see you. this has been beat covered a bunch of times. there's a number of different ways including a very simple fix that doesn't require any time or tooling. exhaust work can get ugly really fast - i'd go with the 7/16" all-thread solution or a bolt. it'll thread in place without dropping the manifold and messing with any more exhaust stuff. otherwise yes you can helicoil it - 10x1.25 is the thread size of the exhaust studs and the size you need. if you're not using new studs make sure you chase them with a die or they might not thread well into your new threads. when using helicoils the exhaust manifold holes are two small for the drill bits to work through so you need to drop it all the way (at least it was on the ones i worked on). or you could drill the manifold big enough for the tools to fit through it, but that seems like extra work too. the 10x1.25 studs are available at auto parts stores - just take on in and match it up. they won't find a match in the parts look up or catalogs, so don't bother trying to find them - none are earmarked for subaru's. but they will have one that works. it's the exacty same length and thread pitch. the only thing is it has a center unthreaded section - just install that section closest to the block - so the part with the smallest amount of threads goes into the block hole. then the non-threaded part will just end up where the exhaust manifold is. if you don't - it ends up where the nut threads on. it's obvious when you go to do it - that's just the easy way to buy them locally and not pay very much. Link to comment Share on other sites More sharing options...
Gloyale Posted July 13, 2008 Share Posted July 13, 2008 I know it'd be nice to keep it all metric, but I'd tap it for a 7/16 (standard) exhaust stud. The stripped metric hole should already be the correct size to run the tap in with a little cutting oil. If for some reason it strips again in the future, you will still have enough meat to helicoil it back to M10. A helicoil will work now, but may come out the next time you try to unbolt the exhaust. A real PITA(just had this happen to the lower *smooth* timing belt pulley mount on an EJ22, it had been helicoiled and we didn't know.) so tapping the block directly for a proper stud is the best option. Use some locktite on the stud so it doesn't come out next time. Link to comment Share on other sites More sharing options...
aircraft engineer Posted July 14, 2008 Share Posted July 14, 2008 Loctite won't hold in the temps in the exhaust. It only goes to about 200C with a short time incursion to 235. It breaks down at hi temps Link to comment Share on other sites More sharing options...
Buick350X Posted July 14, 2008 Share Posted July 14, 2008 pop bottle cap full of salt, with a few drops of water to make a sort of paste, dab some on the threads of the end you don't want to come out and insert home made hi temp locktite Link to comment Share on other sites More sharing options...
Andyjo Posted July 15, 2008 Author Share Posted July 15, 2008 Thanks Guys, I guess i'll go with tapping the holes out to 7/16" and go from there. I think I might go ahead and put the stock exhaust back on it... that or just seal (weld) the crap out of the wrx exhaust this time After this It's time to get some new swapbar links, and put the front sway back on... then the stock bumper, roof racks, and a new passenger side fender and she'll almost be back to stock. Anyone looking for a tube bumper for a 97 OBS? :cool: Oh yeah, I like the Salt/Water Locktite idea! Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now