Use never-seize on diesel manifold?

[dmairspotter]

What is the consensus on using never-sieze (the kind with what looks like copper flakes suspended in grease/oil) on diesel parts, specifically the exhaust manifold bolts?

[Figment]

I dunno about "consensus", but my own personal practice with such things is to either use never-sieze, or to use loc-tite. One or the other.

If it's the kind of thing you're going to undo periodically (more than once every few years), I'd go with never-sieze.
I know a lot of people are leery of using it, but I've never had anything "rattle loose" because of it.

[dmairspotter]

Thanks. I was wondering about galvanic effects but I'm going with it anyway. Like your bolting philosophy too!

[Quetzalsailor]

I would not hesitate to use never-seize as sold for exhaust manifolds on such hot things. I bought some for when I rebuilt the turbo on my Volvo car and used it when assembling the exhaust on my old boat's A4.

I would not use Loc-Tite in such a place unless it was a Loc-Tite product sold for that purpose. Normally, I associate Loc-Tite for the purpose inherent in their trade name which comes in two degrees of gooiness: permanent and removable. Manifold bolts are already likely to be a bear to remove after time in service.

[Figment]

Yes, but after time in service with a coating of loc-tite, you need only break the fairly predictable bond of the loc-tite, which has probably done a fair job of preventing the completely unpredictable bond of corrosion and/or galling of the threads.

[fusto]

If I recall correctly never-sieze can alter your torque specs.
Whether that's an issue in this situation or not, I don't know,
just be careful with the torque wrench.
Broken stud in engine block = much crying

[Quetzalsailor]

Oh, yes, much crying, SHOUTING, CURSING, and money. One of the studs on the Volvo manifold was broken, I bought the specially hard drill bit to drill for an 'easy out', broke that off and had to pay someone to get it out - truly awful.

I broke an 'easy out' off in a Studebaker brake slave cylinder, after breaking the bleed screw off. I took the cylinder off and brought it to McGill University's Faculty of Engineering machine shop where an old German guy looked at it, picked up a stub of welding rod, set his machine carefully and...zapp!, welded the stub onto the broken ends of the easyout and bleed screw. Wound the offending bit out of the slave cylinder when it was still hot.

There really is a difference between mechanics and the rest of us, however intrepid we might be.

[Zach]

I like anti-seize. What I use the most of us Permetex silver. It has a high enough flash point. On exhaust stuff, I put on whatever is handy... eventually its going to get hot enough to burn it off, but I believe the key is getting a layer of something that can turn to carbon between the threads, rather than letting them rust into one.

What I like more is putting a stainless nut on a steel stud... or better yet, a stainless stud and a copper or bronze nut.

Anti-seize is grease or oil loaded with ground up metal dust. Some are better than others... If you are using copper based stuff, its putting a layer of copper and graphite dust between the threads taking up room to keep oxygen out to keep stuff from rusting or corroding together. If its going on aluminum, it'll slowly corrode it...

As far as drilling out these things, grind a flat spot on the top of the nub that is left over. Dremel or die grinder. I normally grind all the way down to the base of the threads and even dish it out a little. From there, center punch it. Start a hole with a drill bit on center. I tend to go a bit bigger than 8th inch... This is a time to throw your hardware store drill bits away and go find a fastenal or other purveyor of american made high speed steel...

After your hole is started, on center... proceed to drill parrallel the threads of the hole. If you drift... step up a size or 3 and persuade it back straight. Sneak up on it, and if you drilled it straight, you'll hit a point where you can see the lumps and bumps where the threads show through. If you run off course, drill it oversize and put in a heli-coil... up to you if you do them all, out of spite.

The key, before reaching for an easy out... is to remove enough material that the grip of the threads is relaxed. Fasteners come into torque by stretching lengthwise... You have to remove enough material that the old stud or bolt relaxes. Then take the easy out to it. I like to spray the whole mess down with penetrating oil a few days before I have to go to town on it. Not to say I haven't broken my share of easy outs... but the biggest thing is to leave them out of the equation until you've loosened it up.

For loosening when the oil just isn't quite cutting it... a mapp gas torch to heat up the head cherry red... a wet rag, ice cubes. Heat causes metal to expand. Localized heat on your stud... causes it to expand inside the rusted out hole. By the time your stud is cherry red, an ice cube will shrink it down. Takes 2-3 ice cubes to cool it down to where it isn't steaming... Heat it up again, burn off the water and spray it down with PB Blaster, Kroil, or any other light machine oil that creeps... Penetrating oils have a suprisingly high flash point, so while it is quite stinky... you can spray a hot part, which often times works the trick.

One of the other keys, is to hammering on said leftover bolt a few hundred times with a ball peen hammer, and or steel drift... loosens up the grab the rust has on the threads. It doesn't take a huge wallop either... lots of light taps. It feels like you are wasting time, but you aren't. A lot of times tapping on a nut will do the trick too. If you don't mind destroying the nut, a cold chisel held at an angle and tapped (lightly... if you tap to hard the cold chisel cuts in...) with oil and heat, a lot of times you'll be able to back it off when impact wrenches, and gorilla might fails. As far as gorilla strength goes... resist the urge to get a bigger and bigger breaker bar or pipe. You'll be rewarded, by fewer snapped fasteners... Break out the ball peen and tap the socket, or the head of the breaker bar as you put steady pressure on it. Don't bounce... Dynamic loading on a 2 foot pipe and a 200 pound human, is a lot higher than the breaking strength of a 1/2 inch bolt... right at the shoulder. Spend some time and look at the thickness you've got to work with at the bottom of the threads. Under even tension the breaking strength is high... under point loaded torsion, not so much.

Keep a set of cheap chinese sockets in your tool box. If you don't go cheap... buy some witworths, or rob your metric stuff. After the nut rounds off once, you can dress the worst of the burrs with a file or die grinder... and then hammer on another socket that is close. You pretty much throw away the socket afterwards... but many a 5.99 socket has saved the day.

Last but not least... after you get these nasty fasteners out... either take a bolt of the same thread pitch and cut a slot along its side with a hack saw or cut off wheel and run it in... or use a preferably not new bottoming tap to clear out the trash.

[Carl-A259]

A different, cheapskate, what's laying around method is this: For a stud or bolt heat with a propane torch quite warm, then touch the bolt with an ordinary candle, let the wax melt ( this works whether working overhead or downward, much like sweating a pipe joint) let cool and back the bolt out. This also works for a nut as well. For a nut without going through all this, get a blunt chisel and hit on the flat side of the nut, this stretches the nut and you can see the nut pull away from the threads on the bolt, then unscrew.
Also the secret process most professionals do when someone brings them an item they broke off a drill in is they simple heat up the drill with a torch till cherry red and let cool slowly, this removes the hardness in the drill bit and then they redrill or if it is large enough a hole they just weld to it and remove.
Permatex Anti seize is the GOOD stuff. I use it on anything that fastens mechanically, whether I plan to remove it or not.