Blue loctite on header bolts

[SpaceCycle]

It seems like the nuts had loosed a bit just in the couple of weeks between putting the headers on and taking them off. Am I OK to use some blue loctite here or would that not be advisable with the heat of the engine?

[PeteS]

Blue likely wouldn’t hold. Loctite makes a red high temp version that would be better. Seems Guzzi used red loctite on about every fastener on my 2025.

Pete

[guzzisteve]

Tighten to 23ftlbs instead of 18 like book says fot 8mm stud, should stay put. If 6mm stud go to 10ftlbs instead of 7. This has worked for me, use red like Pete says if still coming loose.

[John A]

I've had good luck using anti sneeze and schnoor washers. then i keep retorquing between heat cycles untill they take a set. usually about four or five times. otherwise, it pulls the studs out when I go to remove them.

[Perazzimx14]

I've never needed the assistance of thread lock compound to get exhaust threads to get dogfast. Anytime I successfully get them apart I put copper anti- seize on the threads to have a fighting chance at getting them apart again in the future.

Drill and safety wire. Higher torque or lock washers.....anythin g but threads lock compound.

[Dirk_S]

Did you actually torque them to spec? The nuts on my V7 II would often come loose—same with my valve cover screws— unless I made sure to torque them appropriately.

You could also safety wire the nuts. When prep’ing my bike for race school, I did something that I guess wasn’t seen too often—I installed wingnuts and drilled the wings to secure the wire.

[SpaceCycle]

Thanks all, I may start with high temp blue loctite (246) and see how that goes. I worry about over torquing because even the 18lbs of torque bent my aftermarket bracket a bit (see pic) making the bracket hard to remove. I also want to make sure I can get the nuts loose again if I ever needed to.

Did you actually torque them to spec? The nuts on my V7 II would often come loose—same with my valve cover screws— unless I actually torqued to spec.

Yeah, I used torque wrench and double checked with a force gauge on a car tire.

[73 sport]

       LocTite on exhaust systems doesn't work. Use "heat locknuts" with anti seize compound.

[moto-uno]

  I think if you search a bit more you'll probably find that high temp loctite is not exhaust port high . They're pretty easy to check every now and then , aren't they ? Peter

[SpaceCycle]

  I think if you search a bit more you'll probably find that high temp loctite is not exhaust port high . They're pretty easy to check every now and then , aren't they ? Peter

It's not too difficult, I would just like to set it and forget it if possible. I think I read the high temp loctite is rated to 450 degrees F.

[cappisj1]

LocTite on exhaust studs is a really bad idea. Those studs heat and cool there for expand and contract. Tighten or torque them when they loosen up. You can loosen your clamp at the header and muffler when retightening the studs bolts. That will help them settle in a better spot too. New gaskets may not hurt. High temp never seize is actually your friend for header bolts.

[Dukedesmo]

The exhaust manifold nuts on the LH cylinder on my LM2 came undone whilst riding. All of a sudden it got very noisy, one nut had fallen off completely and I'd lost one of the collets.


The nuts were a long, brass nut but obviously worked loose over time, not a fan of locking compounds on exhausts (would they even work at that heat?), I bought some copper exhaust nuts.


They are slightly 'squished' oval and so are tight to get on but importantly don't come undone with heat/vibration and being copper don't seize/rust either.

[chuck peterson]

It seems like the nuts had loosed a bit just in the couple of weeks between putting the headers on and taking them off. Am I OK to use some blue loctite here or would that not be advisable with the heat of the engine?

No on the loctite but consider the gasket between the header and the head (check me on if there is one…im thinking of the 70’s here) the gasket gets crushed when installed…if you’ve been in and out of the exhaust you’ll need to be sure to crush them again…2 times maybe, but maybe new each time is better

I’ve slathered anti sieze on threads and bolts and between headers, crossovers and mufflers while assembling, then heat up everything and you’ll see it liquify…this works great when you try to disassemble it 15 yrs and 100,000 miles later. Clean up the drips..yes torque the header nuts

[Dirk_S]

I forgot to mention switching over to wave washers behind the nut. I’m confident they helped before I went the safety-wire route.

[Moparnut72]

I would try double nutting with Pal nuts. Radial aircraft engine cylinders were secured with these. Might just work well in these applications.
kk

[bronzestar1]

I replaced the OEM exhaust on my '24 V100 Navale a few weeks ago with the Ago big-bore headers, y-pipe, and Mistral muffler.  I used anti-seize on the header bolts, and snugged them down just to where the metal flanges started to bend.  If I had to do it over again, I would've used either wavy washers or lock washers as well.  Reading thru this thread makes me want to check those header bolts again.  They're easy to get to, so that'll be on my pre-ride check list next time I take it out...

[yrunvs]

My take on the header nuts is that more then anything they are not loosening but rather with the heating and cooling cycle and engine vibrations the soft brass Oring is finding its for lack of better word...equlibrium. Sometimes it takes a few tightenings to torque specs before that happens. IMHO loctite is not the answer.

[wirespokes]

Wave washers can't handle the heat. The lock washer you want is Schnoor. They can handle the temps.

I've been told a cap nut is best in this application to help prevent corrosion and the nut locking up.

Another interesting solution to exhaust components 'welding' together is silicone sealer. They may be slightly more difficult to separate, but they certainly won't be rusted together.

[Kev m]

Wave washers can't handle the heat. The lock washer you want is Schnoor. They can handle the temps.

Would you mind educating me why/how the Schnoor would work but wave won't?

I don't have enough knowledge on this to disagree with you, but I sorta feel like there was a period a while back when a bunch of the early 1TB smallblocks were all loosening their header nuts and the replacements a few of us got had what I would call captive wave washers? I could be remembering wrong, but they haven't loosened in years since we replaced them. Maybe I should check and see what I can see or look if I have more spares.

[cliffrod]

…

Another interesting solution to exhaust components 'welding' together is silicone sealer. They may be slightly more difficult to separate, but they certainly won't be rusted together.

The go-to exhaust sealant we used for daily rider shovelheads (including mine) was the hi-temp copper silicone gasket sealer.  Original heads only have a single bolt (or stud to avoid wrecking aluminum threads as easily) to attach exhaust to the aluminum head.   That arrangement leaves a lot to be desired. 

The copper silicone helps a lot, both to seal the connection and keep the single bolt/stud & nut in place, even though it needs to be applied with discretion to avoid the bubblegum look.  Using a dab on threads, HD or Guzzi, to keep nut in place can be almost invisible if done right. 

[Moparnut72]

The go-to exhaust sealant we used for daily rider shovelheads (including mine) was the hi-temp copper silicone gasket sealer.  Original heads only have a single bolt (or stud to avoid wrecking aluminum threads as easily) to attach exhaust to the aluminum head.   That arrangement leaves a lot to be desired. 

The copper silicone helps a lot, both to seal the connection and keep the single bolt/stud & nut in place, even though it needs to be applied with discretion to avoid the bubblegum look.  Using a dab on threads, HD or Guzzi, to keep nut in place can be almost invisible if done right.

This was a staple in our aircraft engine shop. Use sparingly so that it doesn't make a mess as Cliffrod said. The components will come apart easily down the road.We used the Peratex brand.
kk

[SpaceCycle]

Thanks everyone for the discussion and suggestions. I ended up just using some anti-seize and tightening to 18lbs. I'll check it periodically. I may just need to invest in a torque wrench instead of borrowing my Dads' every time!

[wirespokes]

https://www.schnorr.com/serratedsafetywashers

I can't find anything on how they perform in applications of high temperature like exhaust studs. A few of my guzzis came with them, under the exhaust nuts and they don't loosen up, so that's what I base my statement on. It's interesting that the above reference states they're not to be installed upside down, something I hadn't known. Fortunately the right way made sense to me and that's how I installed them in the past. The nut presses on the raised inner surface of the washer.

Thanks Cliffrod! After reading about exhaust stud repairs, I think I'll pull them and coat with copper Permatex.