just as the title stated. i want to verify the thread pitch of the oem o2 housing spring bolts. i had purchased an aftermarket o2 housing from a member on here and notice that my spring bolts dont thread easily into the megan o2 i bought. the bolts do thread into my oem one quite easily. i put a tap into the megan and found a 10x1.5 threadsquite nicely into the megan, but a 10x1.5 die on the oem bolt didnt go so well. The megan doesnt look like it was re threaded or anything so i want to know what the thread is. the oemlooks like its a bit larger than a 10?? Tia

 

to help you out when i swapped to my titek 02 housing, the bolts were actually bigger on the 02 housing then the stocker. iirc I believe my thread pitch was a 12x1.25 or 12x1.5 check if your megan 02 housing is the same. If so get some of the lube for the dye, and run it through your threads to clean them up, and then run the round piece with same thread pitch over the bolt with the lube, so that way you have fresh cut threads. So then it should bite no problem. gl

 

The megan has a 10x1.5 thread pitch and the stocker spring bolts seem larger, so 12x1.5 does make sense but I will verify. Thanks

 

They are M10x1.25

They are Not M10x1.5 or M12x1.25

The DP bolts, and all the bolts and studs that go on the hotside are ALL M10x1.25

 

In a nutshell

 

maybe on yours ct9a but my stock o2 housing to downpipe bolts didnt fit in my titek 02 housing holes, stockers were m10 but these were m12, i had to get two m12 like i said i forgot if they were 1.25 or 1.50....but the m10 didnt fit on mine.

 

Stock downpipe bolts do in fact fit the Megan o2 housing, it is what I run in my personal car.

 

Im assuming the megan/ebay o2 housing is meant to work with the stock spring bolt setup but my oem bolts didnt want to thread into it. This O2 housing seemed to have been threaded for a 10x1.5 and curious to see if anybody else experience this with aftermarket O2 housings.

 

ran a 10x1.25 tap and stock spring bolts thread in just perfect now. previous owner of this must have used a different bolt setup for whatever reason. thanks everyone for the help.