Exhaust Stud woes: Longer barrel nuts? 12mm Copper nuts? Options?

[RarlyL8]

To get the height of spacers you would have to stack washers. I wouldn't do that, the washers have crush requiring re-tightening and stacking them just looks bad.

[RichPugh]

I ordered 12x 057 131 529 G ... I have a feeling they are going to look like this:



Still should work. The 059 131 529s aren't avail thru US dealers so lemme know what you come up with when yours come in. I still may cut down my studs...

[911pcars]

Originally Posted by RarlyL8

To get the height of spacers you would have to stack washers. I wouldn't do that, the washers have crush requiring re-tightening and stacking them just looks bad.

Huh? Aluminum washers have crush (don't use them in this application). There's no "crush" with a flat steel washer(s) at the specified torque. In addition, this isn't like an internal engine component. It's an exhaust manifold. Maybe a little over-cautious thinking here. Rechecking fastener tightness after a few miles, if accessible, is normal practice.

S

[RarlyL8]

Steel washers have crush when you stack them. It takes several washers to make up 3/8", when you tighten all of that there is a lot of movement available for vibration to loosen up. Copper nuts should stop that from happening.

[theiceman]

im beginning to think i am the luckiest guy in the world, these babys had been on for over 40 years in a northern climate.
just took them out and put in the studs i required for my SSI installation. didnt break one.

[911pcars]

Originally Posted by RarlyL8

Steel washers have crush when you stack them. It takes several washers to make up 3/8", when you tighten all of that there is a lot of movement available for vibration to loosen up. Copper nuts should stop that from happening.

I think corrosion does the same thing.

[RichPugh]

Originally Posted by theiceman

im beginning to think i am the luckiest guy in the world, these babys had been on for over 40 years in a northern climate.
just took them out and put in the studs i required for my SSI installation. didnt break one.

Rub it in lol

[RichPugh]

Well... the ones I got look just like the one pictured above but they're a few mm too long... won’t grab the threads... so... back to spacers for now.

[don gilbert]

I've done this to several cars now. Plenty of room to go to 10mm and then I use hardend allens bolts. Can tighten the heck out of them and NO leaks ever.

[theiceman]

Originally Posted by RichPugh

Rub it in lol

im glad i didnt read this thread first as i would have been terrified lol

[911pcars]

Originally Posted by don gilbert

I've done this to several cars now. Plenty of room to go to 10mm and then I use hardend allens bolts. Can tighten the heck out of them and NO leaks ever.

What’s the lesson to learn here? Install oversized fasteners and overtighten as needed? This is Porsche, not Panzer (or Catepillar).

[bpu699]

Don't understand the issue... on my 930 I use regular hex nuts for the exhaust coated liberally in anti seize.

Place your socket extension through the exhaust access holes, THEN put the socket on, and tighten. Voila!

Never had to use any fancy tools or anything...

[mepstein]

Originally Posted by bpu699

Don't understand the issue... on my 930 I use regular hex nuts for the exhaust coated liberally in anti seize.

Place your socket extension through the exhaust access holes, THEN put the socket on, and tighten. Voila!

Never had to use any fancy tools or anything...

This is an aftermarket 914-6 exhaust. There are one or two studs that don't have exhaust stud access through a hole and depending on the engine, may be a little difficult to reach. The distributor wrench helps.

[theiceman]

Originally Posted by mepstein

This is an aftermarket 914-6 exhaust. There are one or two studs that don't have exhaust stud access through a hole and depending on the engine, may be a little difficult to reach. The distributor wrench helps.

yeah i put SSi on and did not have a special wrench , i just used various universals and offset metric wrenches I had and it was fine...

[RichPugh]

Update: I cut the exhaust studs down with my Dremel tool, tapered the cut end and re-threaded (chased) them, and stuck with the stock style barrel nuts... and was able to get them all tight with an Allen key and some ingenuity. No spacers, no stud removal :thumbup:

[Harpo]

Possibly, IMHO it depends on the ID & OD of your spacers. If the spacer ID & OD are similar to your washer they your good to go but if the surface area of your spacer is less then you may end up with embedment or hoop stress in your bolted joint.

[JimmyT]

These titanium exhaust nuts feature:

Deeper allen wrench engagement for more reliable removal
Deeper internal threads for non-standard stud lengths.
External hex allows use of 14mm open end wrench
Reduced corrosion

FS: 911 Exhaust Barrel (Allen) Nuts, 999.085.001.02, $12.14 each