Author Topic: Damn M7 x 45mm Exhaust Flange Studs! (Read 5744 times)

hochiminh · « **on:** May 29, 2010, 05:39:27 PM »

I am having difficulty finding M7 x 45mm exhaust flange studs to bolt my header to my head, both online and in the local hardware stores. I called the stealerships and they want $55 for 12 studs and bolts, to which I kindly said "go to hell." I have managed to locate one place that has M7 x 55 and 45 mm bolts made of steel but am not sure if I cut off the bolt top that it will work. Can anyone confirm this? :confused: Do I need specifically expansion type bolts? Any input is greatly appreciated.

Thanks! and Happy Memorial Day!

B318M42W · « **Reply #1 on:** May 30, 2010, 03:02:07 AM »

I agree that 55$ for 12 bolts is pretty expensive, but i beleive that they are high quality bolts made to sustain and still work properly even when heated. I wouldn't put hardware store bolts on any engine... (well, maybe in a honda engine :p ). But if you still want to go the cheaper route, and cut the bolts, it would be a good idea to chamfer the cut end and pass it through a die to clean up the threads. my .02 cents...

PumpItUp · « **Reply #2 on:** May 30, 2010, 05:23:16 AM »

I don't get it, where did you get that number?
isn't m8 x 45mm what you need, like this
http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=07-11-9-908-368-M9&catalog_description=Intake%20Port%20Stud%2C%208x45mm%2C%203%20Series%2C%20All%2C%20%281984-91%29%2C%20As%20Needed%09%09

or is it this
http://www.rmeuropean.com/Part-Number/Exhaust-Port-Stud-8-X-40-mm-__07129908134_GEN_E095124A.aspx

they're m7 in shrunk form and then they expand. (i think) :confused:

hochiminh · « **Reply #3 on:** May 30, 2010, 02:29:10 PM »

No, according to realOEM it's M7; I also verified it. I guess I should have mentioned that this was for a '91 E30 M42. Might be different for the E36 heads.

hochiminh · « **Reply #4 on:** June 01, 2010, 12:59:22 PM »

bump! any sites/non-dealer carriers of these studs?

PumpItUp · « **Reply #5 on:** June 01, 2010, 04:52:31 PM »

closes size i've found
http://www.rmeuropean.com/Part-Number/Exhaust-Port-Stud-7-X-42-mm-__11121744057_GEN_E095124A.aspx

bro don't trust realoem, for all you know its a typo or they're designed to expand. ask someone who knows what they're talking about like a bmw mechanic or a smart muffler shop. if you figure this out be sure to post

hochiminh · « **Reply #6 on:** June 02, 2010, 02:07:08 PM »

Thanks, PumpitUp. I went to a BMW specialist near where I live (catulpastreetgarage.com), they had 'em in stock! But I ended up paying $38 which was a ripoff still. They are identical to the ones that came out, and went in with ease. Hope this helps out people in the future.

Reference: M7 x 45mm exhaust flange stud. OEM Part #: 07129908199