exhaust mounting hardware

[golf73]

got the "complete exhaust mounting kit" from bavauto and it didn't come with bolts, nuts and washers to connect the center resonator to the downpipe and the rear muffler (did come with the downpipe to manifold bolts and copper nuts). so i have to go to the hardware store. for the bolts, what size and type (metal and hardness?) should i get? i see on Max's site that it should be M8x35 but i'm not sure if that is a common size and shit). what nuts, locknuts, or is it common to just use regular hex nuts and use locktite? what kind of washers?

[wegweiser]

If you can get them - go with grade 8 bolts rather than grade 5.

The 8mm bolts are an 8 x 1.25 Metric thread and 35mm in length -not including the thickness of the head - (sometimes referred to as coarse Metric). Should be easy to find - do yourself favor and stick with Metric fasteners.

oh...and by the way: I've probably sold about 100 of those kits, and they SHOULD include the large 10mm Copper manifold to d'pipe nuts! Maybe the manufacturer is skimping these days - probably not Bav's fault.

HTH

Paul Wegweiser

[Kidasters]

Is this the kit you got?

I used the same kit. I thought the three bolts and copper nuts are for the collector/resonator connection.

I thought that the connection at the manifold to downpipe were studs. I'd use the 12 mm copper nuts on those too...

Ken

[golf73]

If you can get them - go with grade 8 bolts rather than grade 5.

The 8mm bolts are an 8 x 1.25 Metric thread and 35mm in length -not including the thickness of the head - (sometimes referred to as coarse Metric). Should be easy to find - do yourself favor and stick with Metric fasteners.

HTH

Paul Wegweiser

thanks Paul. what about the nuts - locknuts or regular? are washers normally used?

[golf73]

Is this the kit you got?

I used the same kit. I thought the three bolts and copper nuts are for the collector/resonator connection.

I thought that the connection at the manifold to downpipe were studs. I'd use the 12 mm copper nuts on those too...

Ken

yeah that's the kit. you're probably right about the manifold having studs, in that case why don't they include 3 more copper nuts? do they use copper so they don't rust? but then what about the electrolysis of 2 different metals against each other?

anyways, if bav auto's going to claim it has "everything you need to replace the exhaust" i think they should include every nut, bolt and washer. i am replacing the rubber bushings and bolts at the mount at the trans as well, those weren't in the kit either.

in other news, got BMW mufflers from Blunt, they're Boysen brand and look like they're gonna last a LONG time!!! Sturdy as hell! Hopefully no more rattling and unhooked and/or lost exhaust donuts!

[Kidasters]

Good point. They give you the gasket, why not the nuts too?

Maybe you should write them? Seriously.

I didn't think of that, since I have an IE header, didn't need the other stuff.

Otherwise, I really liked the kit. Worked great on the stock exhaust that I just put on....

Ken

[wegweiser]

I'd stop by the BMW dealership and ask for a handful of 8mm (or 10mm if they're for the downpipe to manifold studs) Copper nuts (say they're for an old E30 325i, circa 1989. (If you tell 'em they're for an old 2002, you're just asking for trouble.

They're steel - but have a Copper coating - no worries about bi-metallic corrosion - but you will oh-so-thank yourself if you ever have to remove 'em later on. These should have a 12mm hex head by the way and are self locking. If you can't find locknuts (oh yeah you KNOW.....nylon ones aren't so good for hot exhausts, right?) Use wave washers/lock washers under the regular nuts at least. I use flat washers under the heads of the bolts also - to spread out the load on the flange a bit more.

NOTE: Later cars like E36 3 series used exhaust nuts that were only slightly different - finer thread pitch and 7mm - so make sure you ask for E30 era 3 series ones!!! If your parts guy is asleep at the wheel - you might get the wrong ones and be very frustrated.

A "complete" exhaust install kit would have included the brkt at the transmission, rubber bushings, etc... What Bav Auto sells is a basic kit, as it was / still is- offered through BMW.

Have fun!

Paul Wegweiser

[tjones02]

I like to use some of this copper anti-seize on all exhaust hardware... BavAuto ... Lubro Moly Anti-Seize Compound - 100g

Part # : 2012

The Manifold to down pipe nuts you're looking for are # 18 30 1 737 774 and you'll need 3 of them.

HTH

[golf73]

OK, man, I think I got it straightened out! I got new M6 bolts with nyloc nuts for the trans mount bracket at the hardware store. Now I just need the larger M10 copper locknuts that I'll try to get at the dealer. Now if I can find the rubber bushings for that mount on my workbench amidst my clutter of TR6 parts! Thanks guys!

Ryan