madhatter_xe Posted March 10, 2008 Share Posted March 10, 2008 Hey guys, I managed to get the new engine running smooth but as I was torquing down the header bolts to get rid of an exhaust leak, I stripped one out. Its the upper one on #6 cylinder (rear drivers side). Now i'm driving around with no bolt in the hole and the worst exhaust leak i ever heard. Just wondering if anybody has any tips to get this fixed cheap. I am thinking that I am gonna have to pull the header off and take it somewhere to get drilled and have a heli-coil put in...but I'd like to get it fixed without pulling off the header. Thanks for any info folks. Link to comment Share on other sites More sharing options...
mws Posted March 11, 2008 Share Posted March 11, 2008 Heli coil, or drill and re-tap one size over. You need to remove the header any ways. If you put enough torque on to strip it, you have severely overcompressed the header gasket and it will never be able to seal properly. They should only be compressed a small to moderate amount to seal properly, hence the factory torque specs. Link to comment Share on other sites More sharing options...
madhatter_xe Posted March 14, 2008 Author Share Posted March 14, 2008 Heli coil, or drill and re-tap one size over. You need to remove the header any ways. If you put enough torque on to strip it, you have severely overcompressed the header gasket and it will never be able to seal properly. They should only be compressed a small to moderate amount to seal properly, hence the factory torque specs. Yeah, it kept leaking so i kept tightening. I think the threads may have been weakened from before or something and thats why it was leaking, and then i stripped it right out, it didnt' take much torque to strip it. I picked up a heli-coil kit and it says to drill it out with a 21/64 drill bit. Would you happen to know what size is safe to drill these heads with? i've heard that the water jackets are awfully close to the holes. 21/64 is a 64th larger than 5/16. thanks for any info. Link to comment Share on other sites More sharing options...
Doug_17Fire Posted March 14, 2008 Share Posted March 14, 2008 Just my 2 cents but if it still leaked when you tried to tighten it the exahust headers we warped... I would get new ones while you are at it ...My Pathy has the leak issue .. As soon as it is back on the road I am getting mine replaced .. http://www.car-stuff.com Has stock ones for under $50.00 a side Replacement Rear Right Exhaust Manifold 1987-1995 Nissan Pathfinder 1987-1995 Nissan Pathfinder N960704 $38.27 Replacement Left Exhaust Manifold 1990-1995 Nissan Pathfinder 1990-1995 Nissan Pathfinder N960705 $46.55 Link to comment Share on other sites More sharing options...
mws Posted March 14, 2008 Share Posted March 14, 2008 Yeah, it kept leaking so i kept tightening. I think the threads may have been weakened from before or something and thats why it was leaking, and then i stripped it right out, it didnt' take much torque to strip it. I picked up a heli-coil kit and it says to drill it out with a 21/64 drill bit. Would you happen to know what size is safe to drill these heads with? i've heard that the water jackets are awfully close to the holes. 21/64 is a 64th larger than 5/16. thanks for any info. If that is the helicoil set to put stock/original size threads in, I am 99% you will be fine. I have installed heli-coils for exhaust studs with no issues whatsoever. Just make sure you go in straight, and not too deep! Insert a smaller drill bit or stud or something into the neighboring hole to remind you of the proper angles to maintain. Having someone watch from the side and direct you helps as well. And you'll be able to feel when the drill bottoms to the original hole because progress will slow noticeably. Take your time. Taking 2 hours to do it once will be MUCH faster than if you try to rush and mess it up. Get a small mirror (I like the ones on the extending pointer like stems) and flashlight so you can check progress regularly. Link to comment Share on other sites More sharing options...
madhatter_xe Posted March 14, 2008 Author Share Posted March 14, 2008 Thanks alot for the tips MWS. I borrowed a buddy's 90 degree drill and the process went great, those heli-coils are quite the invention. I think the reason the headers were leaking to begin with is b/c they fit like a pile of dog crap. I never liked how the joints were sort of "massaged" or should I say, pounded to fit and I think that put alot of pressure on the header flange. So i'm going to get the Y pipe bent so everything fits nice and there isn't any pressure on the header. Just my 2 cents but if it still leaked when you tried to tighten it the exahust headers we warped... I would get new ones while you are at it ...My Pathy has the leak issue .. As soon as it is back on the road I am getting mine replaced ..http://www.car-stuff.com Has stock ones for under $50.00 a side Replacement Rear Right Exhaust Manifold 1987-1995 Nissan Pathfinder 1987-1995 Nissan Pathfinder N960704 $38.27 Replacement Left Exhaust Manifold 1990-1995 Nissan Pathfinder 1990-1995 Nissan Pathfinder N960705 $46.55 Yeah I thought the header flange might be warped too, but i checked it and its beauty. So hopefully after getting the fitment issues fixed this won't be a problem. In terms of the replacement manifolds, you might want to check to see if Nissan has developed a decent replacement manifold. To the best of my knowledge those replacement parts will cause you the same grief as the ones that were originally put on the truck. From reading around on this board, headers seem to be the best solution for the annoying exhaust leak. Link to comment Share on other sites More sharing options...
mws Posted March 17, 2008 Share Posted March 17, 2008 Sounds like you are on the path to a true fix! Stressing the heck out of the headers to get the Y pipe on is not good for sealing.... Good on ya! I believe the real root cause to stock manifolds warping is still the studs. After thousands of heat cycles, the studs just get weak and eventually snap off. Once a couple come loose, a leak develops. If left long enough, the manifold warps. So if you were to install new factory manifolds with the upgraded 300zx studs, I would wager big money they will last well over 100K miles - and likely for the life of the truck. Most of us installed headers because we wanted the extra performance and efficiency. And once you're removed everything to fix the studs, it is pretty much just as easy to install headers as replacement manifolds, so might as well upgrade! Link to comment Share on other sites More sharing options...
Kittamaru Posted March 17, 2008 Share Posted March 17, 2008 mws, what are the 300zx studs? Link to comment Share on other sites More sharing options...
mws Posted March 17, 2008 Share Posted March 17, 2008 Seek and ye shall find! http://www.nissanpathfinders.net/forum/index.php?showtopic=28 The actual part number is listed in the broken exhaust stud section. Link to comment Share on other sites More sharing options...
madhatter_xe Posted March 19, 2008 Author Share Posted March 19, 2008 yeah everything is back together and it sounds beauty. no more ticking! I used some grade 8 or 10 bolts with Hex heads on them. they worked great and should hold up fine. Link to comment Share on other sites More sharing options...
GrimGreg Posted March 19, 2008 Share Posted March 19, 2008 Why I skipped the gaskets and just used copper RTV only on my headers. I am even missing a bolt on one (snapped the Snap-On "EZ Out" off in it) and I don't have a leak. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now