Exhaust bolts, can I loosen them up?

[dutchjeep]

I about to embark on the great exhaust-manifold-replacing trip. Any good suggestions to make sure I don't snap those manifold bolts? Can I use lubricants to loosen them up? Which one should I use for that?

Thanks!

[riverfever]

I'd start spraying them with some kind of penetrant like PB Blaster. Hit emseveral times, maybe in the evening so they can soak all night a few times.

[5-90]

Also, DO NOT "snap" the wrench when you're trying to loosen them! Work smoothly and FEEL what's happening - if a bolt is starting to let go, yo'ull feel the difference and you can STOP and deal with it another way.

"Another way?" Sure - if the bolt gets terribly stuck, get a fine-flame torch (a "pencil torch" is just perfect for this - you'll want to heat the head of the bolt red, and touch a block of paraffin (or a candle) to the threaded part of the bolt. The wax will melt and wick into the threads, and will get farther in as the bolt cools and contracts. Let the bolt cool until you can touch it with a bare finger, and try again. It should come loose this time.

Don't reuse the bolts - replace them! I prefer to use bronze or brass, 3/8"-16x1.75". Studs for the ends and the centre can be made from brass allthread rod (3/8"-16 again) - cut to about two and a half inches long. Replace the nuts - the OEM studs have two thread pitches - 16TPI going into the head, and 24TPI under the nuts.

Use LocTite #272 to retain the bolts, and apply a LIGHT coat of RTV copper to BOTH sides of the new manifold gasket before it goes in - it also helps.

5-90

[dutchjeep]

Ok, will use the PB Blaster and will be very carefull. Thanks for the torch-trick! I will certainly make sure not to re-use nuts and bolts. Thanks for the input. Much appreciated!

[dutchjeep]

He, if I use loctite on the bolts will I be able to get the bolts loose again if needed?

[POSXJGuy]

He, if I use loctite on the bolts will I be able to get the bolts loose again if needed?

you can use the blue loctite, not the RED. avoid the Red.
I used antiseize on my manifold bolts. I checked the torque a few times after now that its been 2K miles since the header job and they seem to be holding just fine.

I never thought of loctiting the header bolts actually. i would rather have to check em each now and then rather than have em jam and get busted off the next time i need to remove em for something.

john

[dutchjeep]

Ok, got it, thanks again!

[5-90]

He, if I use loctite on the bolts will I be able to get the bolts loose again if needed?

Yes, you can.

LocTite comes in various "grades"/"strengths" - I don't recall the colours, since I key on numbers, but you select according to your application...

#222 - Low strength. Use for "maintenance" screws (adjustments and such) and most screws under 1/4" nominal diameter. Breaks free with hand tools

#242 - Medium strength. Use on 1/4" and up, may require light heating to break loose.

#272 - Medium strength. Usually breaks with hand tools. Formulated to withstand exhaust heat (don't use anything else, if you want it to work. I tried #222 and #242 once, just to see what happens. Good thing I torqued the bolts properly - I couldn't even find residue of the threadlocker!)

#545 - Hydraulic Sealer. Combines threadlocking and thread sealing in a single compound, breaks with hand tools. Works well on power steering and brake lines.

PST - Thread Sealer. Similar to "Teflon pipe dope" (which I usually use as a substitute,) this will seal threaded joins against water/air leakage. Breaks with hand tools.

#640 - Sleeve Retainer. If you use this on a bolt, make DAMN sure you don't want to get it out again! Requires heat and power tools to break - since it's designed to keep a smooth sleeve in a smooth bore...

Again, use either #272 or NOTHING on exhaust bolts, since nothing else can stand up to the heat!

Bear in mind that using LocTite doesn't change any torque specifications, but the following changes should be considered mandatory (unless otherwise defined, torque specs in manuals are for "clean, dry" threads...)

Engine Oil/Chassis Grease - Listed torque x .67
Teflon Pipe Sealant - Listed torque x .75
Anti-Sieze Compount - Listed torque x .5

Other thread compounds should let you know what changes are to be made. Note that using typical "threadlocker" compounds (LocTite #222/242/xxx) should NOT change the listed torque value for a bolt - they're formulated not to...

5-90

[anony91xj]

Which bolts are you talking about? The bolts in the head or the bolts that connect the manifold to the front exhaust pipe?

The bolts that connect the manifold to the pipe, just snap them off. Use new studs or bolts with the new manifold (the manifold may even come with them).

The bolts in the head usually don't snap, they generally come out pretty easy. Just go slow and take your time to make sure they all come looss nicely. You really don't need Loc-Tite on them when you re-install either. If you do use Loc-Tite, just make sure you get the right stuff. Read the package, colors and numbers vary by brand, "Loc-Tite" is actually a brand name. Some of these compounds have to be heated to pretty high temps before they'll allow the bolt to come loose. Either way, there's no threadlocker on them from the factory.

[5-90]

Which bolts are you talking about? The bolts in the head or the bolts that connect the manifold to the front exhaust pipe?

The bolts that connect the manifold to the pipe, just snap them off. Use new studs or bolts with the new manifold (the manifold may even come with them).

The bolts in the head usually don't snap, they generally come out pretty easy. Just go slow and take your time to make sure they all come looss nicely. You really don't need Loc-Tite on them when you re-install either. If you do use Loc-Tite, just make sure you get the right stuff. Read the package, colors and numbers vary by brand, "Loc-Tite" is actually a brand name. Some of these compounds have to be heated to pretty high temps before they'll allow the bolt to come loose. Either way, there's no threadlocker on them from the factory.

Essentially correct - you don't need to use anything on those bolts. I'm just paranoid. If you do use anything at all, use LocTite #272 or equivalent - the "regular" threadlockers (#222 and #242 - and equvalents) aren't going to work worth a damn with all the heat around there...

Save yourself some trouble as well - see if you can get brass nuts for the downpipe studs. Don't ask me why - ask yourself next time you have to take them off (since it's going to be VERY easy to do!) I don't use steel replacement hardware on exhaust work, haven't for the last 25 years, and for a very good reason...

I've done quite a few posts on this particular job as well - were I you, I'd probably take the half-hour to find them and see what I've missed here (since I'm not thinking in that vein - too much electrical work lately...) I've got to do a decent writeup one of these days...

Also, before you get started, I'd see about getting a 9/16" socket with an inbuilt universal joint. GREAT for getting the lower back bolts, and you don't have to do any "torque adapting" using it. Saves a lot of wear on your nerves and your knuckles...

5-90

[anony91xj]

Save yourself some trouble as well - see if you can get brass nuts for the downpipe studs. Don't ask me why - ask yourself next time you have to take them off (since it's going to be VERY easy to do!) I don't use steel replacement hardware on exhaust work, haven't for the last 25 years, and for a very good reason...

I see you live in SoCal. Try doing that in the North where they salt the roads. All the threads below the nut will rust and rot so bad that nut isn't going anywhere after a winter or two anyway.

I usually just don't use studs for this reason, I'll just shoot a bolt through the hole. If the exhaust ever has to come apart again, I just break them off and use a new set of nuts/bolts/washers.

[5-90]

I see you live in SoCal. Try doing that in the North where they salt the roads. All the threads below the nut will rust and rot so bad that nut isn't going anywhere after a winter or two anyway.

I usually just don't use studs for this reason, I'll just shoot a bolt through the hole. If the exhaust ever has to come apart again, I just break them off and use a new set of nuts/bolts/washers.

Try again - SF Bay Area. However, I did grow up in Lafayette, IN - and I started using brass there wherever possible. Exhaust studs were made from brass threaded rod, underbody stuff was either stainless or brass - and if I HAD to use regular steel, I typically found SOMETHING to coat it with. Always do a job with the mind that you're going to be the next poor schmuck to do it, and when I do, all I have is my Gerber Multi-Plier 600DET and my SwissChamp...

There are sound engineering reasons for material selection - but they always end up using plain steel because beancounters get involved in engineering decisions (a subject about which they typically know slightly less than nothing...)

5-90

[anony91xj]

Try again - SF Bay Area. However, I did grow up in Lafayette, IN - and I started using brass there wherever possible. Exhaust studs were made from brass threaded rod, underbody stuff was either stainless or brass - and if I HAD to use regular steel, I typically found SOMETHING to coat it with. Always do a job with the mind that you're going to be the next poor schmuck to do it, and when I do, all I have is my Gerber Multi-Plier 600DET and my SwissChamp...

There are sound engineering reasons for material selection - but they always end up using plain steel because beancounters get involved in engineering decisions (a subject about which they typically know slightly less than nothing...)

5-90

Brass studs would resist rot a lot better, yes. I thought you were referring to a brass nut on a steel stud. I prefer cheapo steel disposable bolts to expensive brass studs, but I guess either way works. Once you fix an exhaust pipe or manifold, it should be quite some time before it needs to be taken apart again anyway...unless it's a pre-2001 Honda Civic, but that's another story.

Beancounters are the whole reason cars today are made of like 99% plastic...awsome ain't it :D

[dutchjeep]

He, thanks about that 9/16" socket with the universal joint. Will get one for sure!

Tim

[jeepsrock]

I will be getting that APN manifold everyone is talking about to replace my cracked stock on on my 94. I just wanted to check out a few things based on my reading, hopefully a few ppl will chime in.

From my understanding the stock dish washers can be re-used, but the original bolts should not be used. My question is , can grade 8 bolts of the same spec be used ?

On the gasket i should spray a few coats of copper spray on both sides..

Does that all sound ok ?

Thanks
pete

[5-90]

I will be getting that APN manifold everyone is talking about to replace my cracked stock on on my 94. I just wanted to check out a few things based on my reading, hopefully a few ppl will chime in.

From my understanding the stock dish washers can be re-used, but the original bolts should not be used. My question is , can grade 8 bolts of the same spec be used ?

On the gasket i should spray a few coats of copper spray on both sides..

Does that all sound ok ?

Thanks
pete

Yes, do replace the bolts. However, don't use SAE8 - use SAE5. The harder bolts are more sensitive to annealing, and will lose strength faster SAE5, CRES, bronze, and brass will all hold up better than SAE8 - with brass or bronze being best.

DO reuse the dish washers - they're needed to help spread clamp loads.

Spray copper should work - I don't keep any around, so I don't know. I do keep RTV Copper around, and I know that works. THIN layer only, please!

Once you've done the job, would you please confirm the bolt sizes for me? I'm thinking they stuck with 3/8"-16 x 1.5", but I'm not sure. All my data is on RENIX engines.

If you use ISO/Metric screws instead, I'd not go with a property class (stamped into the screw head) higher than 9.8 - same reason for not using the SAE8.

5-90

[jeepsrock]

I dont think the local hardware store carrys bolts in those sizes that are brass or bronze , where does one get those from ?

pete

[5-90]

Try a marina supply store (boats use a LOT of brass and bronze!) or order them from an outfit like Small Parts or Fastenal.

I've been trying to talk my local hardware store into carrying hex head capscrews in brass, and some fine thread and ISO stuff in CRES, but so far unsuccessfully... WiP may end up carrying bolt kits for various jobs, I'm thinking, just so you can get everything all at once without guessing.

5-90

[dizzymac]

I used brass nuts on my downpipe studs two years ago and they still come off easy even though they have gone thru a couple of harsh NE winters and all the road salt we use.

[5-90]

I used brass nuts on my downpipe studs two years ago and they still come off easy even though they have gone thru a couple of harsh NE winters and all the road salt we use.

^^^^^

That, people, is precisely why I use brass undercar. I drive cross-country a couple times a year, so I see it ALL. I try to make things as easy for me to deal with as humanly possible, and it usually pays off.

5-90

[L4V]

Thanks 5-90 and others for the helpful info.
.
A header change may be in my future, so I've been searching/reading.
I found this over in Modified Tech Discussion the other day.
An excellent straightforward tutorial on header R & R done up by 53guy...lots of photos.
.
http://www.naxja.org/forum/showthread.php?t=95384
.
That Doug Thorley ceramic header is sweet, eh?
'Still haven't decided which header to buy...it won't be that DT ceramic, I know that.

[jeepsrock]

Thanks 5-90 for your advice, i ordered the apn manifold a few days ago should be here today, so hopefully i can try to get it in this weekend.

On the gasket do i smear RTV copper on it or do i put a small bead on the edge (both sides ?) ?

thanks
pete

[POSXJGuy]

Thanks 5-90 for your advice, i ordered the apn manifold a few days ago should be here today, so hopefully i can try to get it in this weekend.

On the gasket do i smear RTV copper on it or do i put a small bead on the edge (both sides ?) ?

thanks
pete

you can use the permatex copper spray. dont smear nothin of you dont need to fill gaps. use the spray once on both sides, let sit and do it again and it'll be ready by the time you get to using it.

[5-90]

You can use the spray - the main reason I don't is because I don't have it.

Besides, just because you don't need "gap-filling ability" now, doesn't mean you won't later. The screws tend to work loose over time (that's why I'm experimenting with Bellevilles...) and I do tend to retorque everything once a year. The layer of RTV helps to preserve the gasket for when the screws start to work loose...

5-90

[jeepsrock]

Well here is an update.

I got the manifold in FRI and installed in SAT. THe whole thing took no more than 3 hours and i can honestly say a big portion of it was messing with that stupid power steering/ bracket thing.

I used a small bead of copper RTV on the gasket tho strangley enough when i satrted the car after the install the hood area smoked for a good 3-4 min, i think it was the RTV. Nevertheless i think its all working well.

I personally dont feel any difference but hear my flowmaster better.

As far as the bolts , one of them was especially pain in the arse but the rest were ok to get to with a ratchet wrench.

What can i do to make sure there arent any intake / exhaust leaks ?

thanks
pete

[5-90]

Well here is an update.

I got the manifold in FRI and installed in SAT. THe whole thing took no more than 3 hours and i can honestly say a big portion of it was messing with that stupid power steering/ bracket thing.

I used a small bead of copper RTV on the gasket tho strangley enough when i satrted the car after the install the hood area smoked for a good 3-4 min, i think it was the RTV. Nevertheless i think its all working well.

I personally dont feel any difference but hear my flowmaster better.

As far as the bolts , one of them was especially pain in the arse but the rest were ok to get to with a ratchet wrench.

What can i do to make sure there arent any intake / exhaust leaks ?

thanks
pete


Check torque on them in a week.

I find the rear lower screws are FAR easier to get to with about a foot or so of extension (I think I actually use a 10" bar) and a 9/16" socket with an inbuilt universal joint (I believe I mentioned that earlier...) which will give you a good inch or so of extra clearance over the universal joint/socket combination. If you don't have one yet, get one (and get one in 7/16" or 11m/m while you're about it - that, and about two feet or so of extension will make CPS changes much easier as well...)

RTV Copper is a help on the manifold gasket and on the converter flange gasket (small square gasket - it's on RENIX, but I'm not sure about later models...) as well. You'll probably get a little smoking from it on first startup - I think I did, after letting it cure overnight (~12 hours minimum.)

5-90

[jeepsrock]

Hey 5-90 had a few questions for you...Today i drove the jeep and some how it does feel a bit weaker, i did reset the ecu does it take a while - i drove it a few miles ? ?

Also in the morning when i first start it up cold start, if i lightly press the gas pedal the engine bogs down a bit if i press a bit harder the RPMs go up like they should.

Another thing also is if i rev the engine up in park , the exhaust pops kinda like a old car does.

pete

[CartsXJ]

He, thanks about that 9/16" socket with the universal joint. Will get one for sure!

Tim


Actually a rachetting (spelling) 9/16 wrench, straight or angled will also be very helpful. Specially if you have a BANKS or APN header, good luck getting a socket on the lower bolts.

[Gator4x]

PB blaster works great on the exhaust studs/bolts. If you have a weepy valve cover though, you may find several of the bolts are fairly easy to take off. :D

The smoke isn't gasket sealer. It's manufacturing byproducts, residues if you will (or any crap you might have gotten on your header while installing) burning off your header. It's perfectly normal and will stop quickly.

You don't need to apply a thick layer of the gasket maker. If the bolts come loose it's not going to "fill in" the holes. The purpose of it is to help the two different surfaces conform to one another when you assemble. It's job is to fill in super tiny holes and imperfections in the surfaces. Copper spray helps you apply a thin even layer over the surface. If you can apply a thin uniform layer of copper by hand then go for it.

Reusing the stock hardware is also absolutely fine. If you can clean them up well and the threads and heads aren't damaged there is nothing wrong with reusing them. They aren't at too high of a torque value for their size, and are not put under terrible stress.

Loctite is not necessary either. The joint is designed well and has more than enough bolt stretch in it to not need any type of thread locker. You'll be hard pressed to clean thread locker out of the threads in your head if you do have to remove and reinstall your header multiple times.

If you reuse all the stock parts you can use a little bit of anti-sieze on the threads if you like, but you don't have to.

I don't know about the brass bolts there...the bolt stretch will come easily with the brass, but the bolt itself won't be under as much tension since it's so much softer. You might want to use loctite if you go gonzo and stick brass in your block.

As well torque values are usually calculater from the fastener. Depends on size, threads, material, etc. If you're changing material your changing that equation so the torque number won't work out the same. Like I said before, just don't mess with the brass. -I'm all for it though on the collector-mid-pipe connection. I'd probably just use stainless, but brass would work too. Don't worry about the torque there, just crank the heck out of it.

later,
Nick