Exhaust Nuts

hambone · Post by **hambone** » Mon Mar 09, 2009 11:18 am

Yes I am.
Hoover goes off on his soapbox about only using brass/bronze nuts on exhaust studs. I have a German kit that does have such nuts, but they are for the clamps. Steel nuts have been provided for bolting up the exhaust. Is this OK?

spiffy · Post by **spiffy** » Mon Mar 09, 2009 11:22 am

Use anti seize. I have had good luck with non steel flavors so far.

hambone · Post by **hambone** » Mon Mar 09, 2009 11:24 am

Antiseize and nonsteel? OR with steel nuts?

spiffy · Post by **spiffy** » Mon Mar 09, 2009 11:28 am

hambone wrote:Antiseize and nonsteel? OR with steel nuts?

Yes

hambone · Post by **hambone** » Mon Mar 09, 2009 12:29 pm

I figured as much, but then ol Hoover comes outa left field. Well in an airplane I can see using the best available. Unless I drive off the road up in the mountains.

spiffy · Post by **spiffy** » Mon Mar 09, 2009 1:02 pm

like I mentioned, whatever you use apply the anti seize so you stand a better chance of getting stuff apart down the road.

Post by **Amskeptic** » Thu Mar 12, 2009 10:34 am

hambone wrote:I figured as much, but then ol Hoover comes outa left field. Well in an airplane I can see using the best available. Unless I drive off the road up in the mountains.

I use copper on all exhaust, PARTICULARLY the exhaust manifolds.
You want the nuts to be the weak link when it comes time to take the nuts off. If you have a steel nut that has married itself to the exhaust stud, you run the risk of snapping the stud when it comes time to take apart, but worse yet for airplanes, you run the risk of weakening the stud with no visible evidence of having done so. Copper you can destroy if neccessary and keep the stud intact. If I have any hot application fastener that is not an accessible bolt and nut, such as head studs and Type 4 muffler studs, guess what? Copper, baby. With copper anti-seize.
Colin

TrollFromDownBelow · Post by **TrollFromDownBelow** » Wed Apr 08, 2009 3:06 pm

Thought I'd build on this thread. My nuts keep coming loose. They aren't stripped. I've gotten underneath the bus 4 or 5 since the install, and everytime they are loose.... yes, am using a torque wrench set at 17lbs.

What should I use? lock washer? loc-tite?

Post by **Amskeptic** » Wed Apr 08, 2009 7:16 pm

TrollFromDownBelow wrote:Thought I'd build on this thread. My nuts keep coming loose. They aren't stripped. I've gotten underneath the bus 4 or 5 since the install, and everytime they are loose.... yes, am using a torque wrench set at 17lbs.

What should I use? lock washer? loc-tite?

The nuts themselves are not loosening. The studs are simply pulling straight out of the head.
17 ft/lbs, by the way, is too tight. 16 is spec, and I refuse to go beyond 15 myself.

Your first option is to tap for 9mm hole and install 9X8 step studs.
Colin

Gypsie · Post by **Gypsie** » Wed Apr 08, 2009 10:42 pm

Amskeptic wrote: The nuts themselves are not loosening. The studs are simply pulling straight out of the head.

If you want to test the theory mark the nut and the flange (a simple score line will do). I believe you'll find that the nut has not turned and yet it is still loose.
Aluminium/steel/high torque (considering the size of the hole)/and heat often don't play nice together.

Amskeptic wrote: Your first option is to tap for 9mm hole and install 9X8 step studs.
Colin

=D>

TrollFromDownBelow · Post by **TrollFromDownBelow** » Thu Apr 09, 2009 6:59 am

I'll retorque ... haven't fired it up since I retightened. IRR, I believe we already put step studs in last time you were here.

Post by **Amskeptic** » Thu Apr 09, 2009 8:25 am

TrollFromDownBelow wrote:I'll retorque ... haven't fired it up since I retightened. IRR, I believe we already put step studs in last time you were here.

Timesert City is your next stop. We had step studs?
Colin

TrollFromDownBelow · Post by **TrollFromDownBelow** » Fri Apr 10, 2009 9:26 am

I had ordered new studs, and remember the conversation. I'm going to paint a thin line with white-out as suggested to see which is moving. Believe I bought the nuts at the local hardware store... metalurgy could be that they are expanding much faster than the stud, and loosening up...at least that's what I'm hoping

The fact is ALL of the nuts are loose...have a hard time believing all of the studs are pulling out.

TrollFromDownBelow · Post by **TrollFromDownBelow** » Mon May 18, 2009 5:20 am

just thought i'd follow up on my little experiment....painted white out on the studs/nuts. Nuts didn't move...AND everything is still tight after several hundred miles..woohoo! I'm guessing everything finally settled.

Itinerant Air-Cooled

Itinerant Air-Cooled

Exhaust Nuts

Exhaust Nuts