I was installing the bolts that connect the downpipe to the O2 housing and one wouldn't go in by hand after many attempts so I put it in using a socket and it was much harder to turn than the other one with the socket. The O2 housing was coated by swaintech and I am not sure if there was coating in the threads that could have caused this or if the thread wasn't tapped right to begin with since I had to enlarge one hole so that the O2 housing would mate to the turbo. I am worried that the threads on the bolt or O2 housing may be stripped. How likely is it that the a stripped bolt would stay in against the force of the spring on the O2 housing to DP bolt?

 

you wont have a proble just keep an eye on it,the problem will start when you try to remove them again

 

Yeah thats what I figured, I was wondering though if the fact the spring hasn't pushed it out means that its not stripped? I was going to to get a TBE but if the O2 housing needs to be replaced that could really lengthen the time it takes to do a simple mod. I did the manifold and the O2 housing at once and it was a pain in the ***.

 

The word "stripped" is used to often and often incorrectly. What you most likely did by the description is cross threaded the bolt thanks to some misalignment between the parts. If it is crossthreaded the fastener started to damage the threads on the way in or cut new ones (common in aluminum and plastics). At some point a bunch of material binds up and galls the crap out of the male and female threads. Another common occurrence is the blunting of the tips of the threads (common with misalignment) that changes the dimensions of the threads. Either way, friction goes up like crazy, and therefore heat. That bolt isn't going to fall out. The two most likely end results of this are the bolt breaking on the way out when it finally locks up, or if it's a real strong fastener, like the turbo to manifold bolts, the threads on the bolt would rather stay in the female threads and you'll pull a bare shank out (extreme case of stripped threads).

When putting fasteners into parts that either rust excessively (cast O2 housings, etc) or are coated (high temp coatings, powder coating, chrome plating, etc), the best thing you can do is run a tap through them before installing to clean up the threads and guarantee some kind of minimum clearances. Any self respecting DSM/EVO owner should own a set of metric taps. Most affordable sets won't include a M12x1.25 (for those DP to O2 housing bolts. ), so pick one up seperately if necessary from www.mcmaster.com or whatever you prefer.

Additionally, ensure the alignment of the parts will allow the fastener to go in square. You did the right thing by modifying that one hole, but sometimes it's not enough if you aren't thorough.

Good luck!

 

Thanks for the advice, is this something i can use helicoil to fix once I do remove the bolt?

 

As a little addition to the advice above, when buying a tap for this kind of use you want to buy an undersize tap, sometimes called a chasing tap, which cleans the threads but does not enlarge the existing hole. If you use a new full size tap in an existing hole, you'll end up with a larger hole than you had, and your fastener will not have the same thread depth that it's supposed to...

 

The evo isn't a union made piece of crap that you can ****** in the fasters and expect them to perform right. Many components are tight fits and you have to forcibly align the parts before assembly