Exhaust bolts

[Steve]

Here's a quick question-

I'm going to look for studs and acorn nuts today at the local hardware store. Should I opt for stainless of would zinc work? Do they need to be a particular grade (like G8, etc.)? I wouldn't think so, but thought I'd ask. Finally, I should use anti-seize regardless of plating? I had been thinking Lock-tite to keep them in place...

Stainless would probably work, not sure how much the strength of stainless degrades (if any) when it gets hot.

Nothing stronger than the standard "grade" is necessary, there is not a whole lot of stress on those bolts.

Anti-seize vs Loc-tite? Do you EVER anticipate removing the pipes again? If you are comfortable with the idea that you may never, EVER have to remove your exhaust pipes FOR ANY REASON, go ahead and use the Loc-tite. Not sure how well the blue stuff handles heat, but I do know that the recommended way to loosen the red stuff so you and remove the bolt is to heat it. How well is it going to hold with rather constant heat on it? Anti-sieze and proper torque should work well.

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[Good Times]

I would go stainless steel with anti-seize. SS won't rust and the AS will keep it from sticking. Those are both good things.

[Sojourner]

I get what you're saying Steve, but I was planning on moving to studs so I wouldn't have to remove them ever again. It'd be the acorn nuts (and washers/lock washers) that would need to come off once in a blue moon. It's the studs I was going to possibly Lock-tite, not the nuts.

[Steve]

In that case, go for it.

By the way, "once in a blue moon" happens more often than most people realize.

From Wikipedia:
The following blue moons occur between 2009 and 2021. These dates use UTC as the timezone; exact dates vary with different timezones.

Seasonal
Using the Maine Farmers' Almanac definition of blue moon (meaning the third full moon in a season of four full moons), blue moons occur

• November 21, 2010
• August 21, 2013
• May 21, 2016
• May 18, 2019
• August 22, 2021

Calendar
Unlike the astronomical seasonal definition, these dates are dependent on the Gregorian calendar and time zones.

Two full moons in one month (the second of which is a "blue moon"):[14]

• 2009: December 2, December 31 (partial lunar eclipse visible in some parts of the world), only in time zones west of UTC+05.
• 2010: January 1 (partial lunar eclipse), January 30, only in time zones east of UTC+04:30.
• 2010: March 1, March 30, only in time zones east of UTC+07.
• 2012: August 2, August 31, only in time zones west of UTC+10.
• 2012: September 1, September 30, only in time zones east of UTC+10:30.
• 2015: July 2, July 31
• 2018: January 2, January 31
• 2018: March 2, March 31
• 2020: October 1, October 31

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[GateKeeper]

use anti seize, no locktite required, get your acorn nuts and some lock washers, torque properly and your good to go

in my opinion

.

[7981GS]

Here's a quick question-

I'm going to look for studs and acorn nuts today at the local hardware store. Should I opt for stainless of would zinc work?
Do they need to be a particular grade (like G8, etc.)? I wouldn't think so, but thought I'd ask. Finally, I should use anti-seize regardless of plating? I had been thinking Lock-tite to keep them in place...

I use grade 12.9 studs and grade 8.8 or 10.9 nuts.
If one of them were to strip, you would rather it be the nut than the stud.

Eric

[Sojourner]

I use grade 12.9 studs and grade 8.8 or 10.9 nuts.
If one of them were to strip, you would rather it be the nut than the stud.

Eric

So where did you get your studs? I checked two different AutoZones, an AdvanceAuto, and a Pep Boys and couldn't find anything.

[7981GS]

So where did you get your studs? I checked two different AutoZones, an AdvanceAuto, and a Pep Boys and couldn't find anything.

http://www.metricmcc.com/

They have EVERYTHING metric!
Perhaps there is a location near you or just call them and place an order.

Eric

[Sojourner]

So do yours have the little square nub about 5-6mm long? I've found a ton of M8 x 1.25 bolts, but they all have that little unthreaded square nub at the end. I wasn't sure if that would cause a problem or not. I guess I could just put the nub end into the head? There plenty of threaded rod still. Can't rightly do it with the nub at the acorn end since the nub wouldn't give the acorn anything to thread onto.

Also- do you have the part numbers from your order? What length did you get?

[loud et]

you can see in my pic on the first page that mine do have the small nubs on the end. I think they are 6 mm hex. They must be for assisting in installation.
I know that if the stud does not bottom out when in its installed position it will start to turn when you go to torque the nuts on for the exhaust flanges. with that 6 mm nub , you can hold it in place while you tighten the flange nut. I would NOT personally put the nub end into the hole, that will be 3-5 additional threads that you are giving away for holding strength.
I think mine looks good....good enough for me at least.
Studs of any sort are a better choice imo.
ps(dont obsess too much) do your best and ride!

[cableguy]

When Steve's around it just rains knowledge :-)

[chuck hahn]

I use 2 inch stainless set screws with the allen head setup in the ends. I leave the allenn head end out to use for installation into the head. Also stainless washers and nuts. Fully threaded ones too. Now here is where you MUST PAY ATTENTION FOLKS!!! THERE ARE OIL GALLEYS THAT RUN THRU THE HEAD RIGHT BEHIND THE EXHAUST BOLT HOLES!!!!!!!!!!! Take a wire or the depth measuring end on your dial callipers and MEASURE THE DEPTH OF THE HOLES. Then you can mark each stud and stop when it gets flush with the head. I have heard of some people cutting a small piece of wood dowel and putting that in each hole to act as a stop when installing studs so the dont break in to any galleys. The dowels will simply burn up and dissolve in the holes eventually.

Another trick is to run a tap into the head to refresh the threads and clean any corrosion and scale out..this willl help the studs go in easier and make it easier to tell when they hit into the dowel stops in the holes. Be sure to blow the holes out real good with lots of air when youre done chasing the threads.

[GS ace]

Spraying CLR or Limeaway into the holes is always a must for me. I let it sit for a while then flush it out. I then use a brass bore brush.

[Road Rash]

Stainless can really seize up under repeated heat cycles, and with aluminum heads, well, the head is gonna lose. I work with stainless components at work every day. What they told you is sound advice.

[sedelen]

The gents at my semi-local fasteners shop told me not to use stainless for manifold studs because I'd just end up snapping them if I ever need to remove them. They didn't sell a regular steel stud there. Is stainless really something to avoid for exhaust applications? Does anyone know where I can find a stud kit in Toronto?

I'm using stainless for my manifolds, but I've always had 2nd thoughts about it. I know how stainless works with aluminum. I've seen the damage
on outboard motors used in salt water. Electrolysis. I did however use a healthy dose of anti-seize on the treads and I know they're not sticking (yet) because I just tightened them up a bit a week ago.