My nuts are squished - is this normal?

[patssle]

2 years ago I purchased some exhaust nuts from PP for my 3.0L engine. I'm finally getting around to using them. They seem to be very difficult to screw onto the exhaust studs. I went back to look at what I purchased - they are no longer listed under Porsche. They seem to be BMW nuts - Copper Lock Nut, 8mm 18-30-7-620-549-M58. But they are squished...oval. Is this normal to use?

[mreid]

Yes, that is a deformed lock nut. A nylock would melt in an exhaust manifold application, so an all metal lock nut is in order.

[Ronnie's.930]

Based on yer thread title, I was going to suggest you talk to a doctor rather than seek message board advice!

[patssle]

Are all exhaust nuts deformed? The previous ones I took off don't seem so oval and aren't as hard to put on. I was hoping to use new nuts and not have as much pressure on the exhaust studs if I need to remove them.

[HawgRyder]

They can only be used once.
The thread hole is forced back into more of a circle once they are used.
Bob

[speednme1]

Originally Posted by patssle

Are all exhaust nuts deformed? The previous ones I took off don't seem so oval and aren't as hard to put on. I was hoping to use new nuts and not have as much pressure on the exhaust studs if I need to remove them.

go to belmetric.com for exhaust copper nuts if Pelican doesn't carry them. and no exhaust nuts are not suppose to be deformed. replace with new ones....on another note to avoid squished nuts, a jock strap may be in order...sorry couldn't help myself..

[The cap'n]

Well, they're NOT copper, they're copper plated steel. Porsche NEVER used lock nuts of any kind in any location on any exhaust system on any normally aspirated air cooled production engine. You're only increasing the likelihood of broken exhaust studs somewhere down the line. I don't care what you saw on the internet, what you read in a magazine, or what the salesman told you, they're all wrong. Porsche has more engineers than they do, and would have used locking hardware if they saw any benefit in doing so. After all, they've been at if for 50 years, and that's long enough for the need to show up. (Hint: It didn't.)

The Cap'n

[patssle]

Thanks guys. I'll be getting some non-squished nuts then. Glad I double checked because I sure don't want any broken exhaust studs.

[Ronnie's.930]

Originally Posted by speednme1

...on another note to avoid squished nuts, a jock strap may be in order...sorry couldn't help myself..

Or maybe hire this guy?!

[SilberUrS6]

Ronnie? In a thread about squished nuts? Color me surprised.

[Ronnie's.930]

^^^ Watch it bud, or your special Titanium jobbers might get a bit of unwanted structural reorganization!

[porschetub]

Originally Posted by Ronnie's.930

^^^ Watch it bud, or your special Titanium jobbers might get a bit of unwanted structural reorganization!

Yep BMW use this system ,all my old 5 series had then in various locations mainly in parts off the running gear.
These aren't Porsche standard fastenings,the correct ones are a barrel nut with a 8mm thread then broached half way to the other end for a hex key,no room for a conventional nut in there.
Darn... probably cost more to send them back.

[timmy2]

I used them on my exhaust and have removed them no problem. I even reused them.
Again, no problem.

[otto_kretschmer]

Originally Posted by patssle

They seem to be BMW nuts - Copper Lock Nut, 8mm 18-30-7-620-549-M58. But they are squished...oval. Is this normal to use?

ahh... I see the problem

you bought BMW nuts and you will need BMW tool no. 3.14159xyzpdq to unsquish them

anyone who has worked on BMW motorcycles will know what I'm talking about

[mikesride]

Eccentric lock nuts are fairly common but I've never noticed them used on any exhaust manifold I've ever had.

[mreid]

They are holding the headers on the 3.6 in my 74 911 nicely. You guys with the Porsche engineers this and Porsche engineers that crap are misled. These are the same engineers that installed thermal exhaust, soft valve guides, unreliable chain tensioners, and questionable IMS. Did you really mean to write that?

[Ronnie's.930]

^^^ Don't forget head studs that snap if the wind blows the wrong direction (dilivar)!

[The cap'n]

Originally Posted by timmy2

I used them on my exhaust and have removed them no problem. I even reused them.
Again, no problem.

And I've had to drill out 6 broken exhaust studs on a single 2.7 engine, all having had lock nuts installed. Anecdotal evidence on a one person level is pretty well meaningless. BTW, reusing them means the second time they're installed they're essentially non-locking nuts.

The Cap'n

[timmy2]

Originally Posted by The cap'n

And I've had to drill out 6 broken exhaust studs on a single 2.7 engine, all having had lock nuts installed. Anecdotal evidence on a one person level is pretty well meaningless. BTW, reusing them means the second time they're installed they're essentially non-locking nuts.



The Cap'n

And your anecdotal evidence of drilling out one cars exhaust studs is so much better??

I am not the only one that has posted they are currently using them. Nor did I challenge your mechanical engineering degree and experience working for Porsche as a design engineer.

I just posted my personal experience using them, just like any other poster providing information based on what they have done.
What works for some may not work for others.

Opinions are like a$&holes everybody has one.

Carry on though, some of your posts are very interesting to say the least.

[The cap'n]

No, my anecdotal evidence is no better than any other. They're all equally unimportant in the larger scheme of things .....................................

The Cap'n