# Exhaust Bolts



## nervous (Nov 15, 2015)

Well, my parts are finally here, all broken bolts drilled and tapped and I'm ready for reassembly this weekend. I want to try to avoid any future exhaust bolt issue and am wondering what, if anything, you all use on these threads on assembly? Copper gasket goo, anti seize, loctite, something else, nothing else? I'd like to keep them decent enough for the next time I might need to remove them if possible. 

Thanks.


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## ELaw (Feb 4, 2015)

I'm going to be replacing my muffler soon and I'm planning to replace the bolts with stainless ones. That's of course assuming they're not some impossible-to-get odd size, but that's pretty unlikely.

And regardless of the bolts used, put some anti-seize on the threads!


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## Motor City (Jan 6, 2014)

If you are going to use anti seize, it as to be the nickel version. Its for high heat applications.


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## Kiss4aFrog (Nov 3, 2013)

Loctite 51346 or something similar. I think the specs said good to 2,700 deg.










I use the regular anti-seze that's rated to 2,000 deg. Well in the product specs it said 2K I see on the bottle it's 1,600. Isn't that interesting ??


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## ELaw (Feb 4, 2015)

I think using high-temp anti-seize could be a good idea, but there are a lot of different kinds of high-temp anti-seize, not just nickel. And I don't think you really need the fanciest stuff.

Permatex copper anti-seize (#09128 for the 8-oz. bottle) is rated to 1800 degrees F. The threads we're talking about go into the engine block... and on average the upper engine block temp on an engine like this runs around 300 degrees F. It's no doubt a bit higher around the exhaust port, but it's certainly not 1800 degrees... aluminum melts at 1200 F!

Actually even the regular "silver" Permatex stuff is rated to 1600 degrees which is probably sufficient.


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## ELaw (Feb 4, 2015)

Kiss4aFrog said:


> I use the regular anti-seze that's rated to 2,000 deg. Well in the product specs it said 2K I see on the bottle it's 1,600. Isn't that interesting ??


It's 2,000 before taxes, 1,600 after. :signlol:


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## bad69cat (Nov 30, 2015)

I have been using the copper stuff for years without issue on automotive stuff. Use it on electrical connectors too..... works like a champ


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## Kiss4aFrog (Nov 3, 2013)

Myself, I just use the regular Permatex stuff and it's worked well. I have the 8oz bottle and it's enough to last a decade or two.

I've always used it on sparkplugs and I've never had one stick. Never really thought about the high heat stuff but if it's working for the spark plugs it should also be fine for the headbolts.
The exhaust bolts on my turbo Volvo ... that might be where the high heat stuff would be useful. :biggrin:
It also comes in a smaller tube and most auto parts stores also carry little packs of it.


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## YSHSfan (Jun 25, 2014)

ELaw said:


> It's 2,000 before taxes, 1,600 after. :signlol:


:icon-sadwave:, might be the other way around.... :icon-hgtg:


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## pfn (Dec 24, 2010)

ELaw said:


> I'm going to be replacing my muffler soon and I'm planning to replace the bolts with stainless ones. That's of course assuming they're not some impossible-to-get odd size, but that's pretty unlikely.
> 
> And regardless of the bolts used, put some anti-seize on the threads!


+1 on the anti-seize. I put anti-seize on any bolt, bearing or anything else the might seize that I may want to remove in the future. Otherwise loc-tite.


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## nervous (Nov 15, 2015)

Thanks everyone, really great and helpful info here. I guess one moral is that I'll be fine with my basic silver stuff. I did stop at a local Advance Auto looking for some hi temp variation but was met with the expected crossed-eyes and cocked head of confusion. Oh well. I work with what I have. The second take away is the validation of my using it on all the threaded connectors so far on reassembly. I may never need to remove them again but I am happy with some level of comfort that I can if need be. This one has been a mess so far. 

I did find myself with a self inflicted situation on reassembly today though. It turns out that despite my best efforts to drill out the broken engine head exhaust studs and re-tap I learned that I did them both about 1/16" inward from their normal centers so I now have about a 1/8" discrepancy between the head holes and the manifold holes. I totally missed this before today. Thought I was royally f-ed now. But I think that I have been able to modify the inside manifold holes sufficiently to allow the stock bolts to be used. I will apply a schmear of copper gasket maker on both sides of the nee gasket just to insure a solid seal.

Speaking of the exhaust gaskets. I removed paper/fiber gaskets and have always seen these in use. However I was sent aluminum gaskets which have me a bit confused in their correct orientation for installation. Does the 'positive' round side face the head or the manifold? Or does it not matter once crushed? How about on the manifold/muffler connection?


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## 94EG8 (Feb 13, 2014)

ELaw said:


> I'm going to be replacing my muffler soon and I'm planning to replace the bolts with stainless ones. That's of course assuming they're not some impossible-to-get odd size, but that's pretty unlikely.


That's very likely. Most exhaust bolts have a weird shoulder on them, usually extra long with a very short threaded section at the end. Using a regular bolt just keeps crushing the muffler as you tighten. Also keep in mind that while stainless wont rust it does have a tendency to gall.

A bit of neversieze goes a long way, as does hitting the end of the bolt before making an attempt to remove it.


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## ELaw (Feb 4, 2015)

Well I've researched it a bit and as far as I can tell the only weird thing about the bolts is their length.

The part is Tecumseh #651002, and looking at photos from people that sell them, they're pretty normal... except the threaded part is a little less than regular part-threaded bolts.

But the length definitely is odd: they're 4-3/16" long! But I probably can buy a 5" bolt and cut it to length. Or a 4-1/4" bolt and add a washer if necessary.

Or I could just quit being obsessive and buy a new pair of OE bolts. The ones on there now have lasted 20 years - another 20 years of service for the cost of two bolts is quite a bargain!


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## nervous (Nov 15, 2015)

The OE shoulder bolts for my application were not expensive and as part of a larger order were a no brainier for me. But given my current situation if I had to go to a non shoulder bolt for the added clearance I'd have no problem with that.


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