SS bolts on exhaust yes or no
#1
SS bolts on exhaust yes or no
I saw a recent post that suggested using Stainless steel bolts on my WZ exhaust manifolds might not be a Good idea. I know SS doesn't have the same strength as a steel bolt but the torque spec is only 25 ft lbs. I though using the SS would be good to keep the fasteners from rusting and prevent them from seizing.
When I removed the original bolts one broke off and another one almost did but I got the save on the second one. I would like to avoid that in the future.
Any one have any opinions or experience on this
When I removed the original bolts one broke off and another one almost did but I got the save on the second one. I would like to avoid that in the future.
Any one have any opinions or experience on this
#2
I would avoid SS bolts if I were you. John Deere uses them on there 8.1L diesel and ford used them on the 6.4L diesel. They can't take the heat and just snap off creating an exhaust leak. Not only that but they seize in the hole and have to be drilled out. I know you had one snap off and almost a second one do the same. But how long were those bolts in there? you were trying to remove them; The SS bolts just snap off by themselves. Just use good automotive grade bolts and anti seize. Jmo
#4
I also would like to know what is the best combination to use. I'm unsure about the best hardware type, but I am a supporter of using the best high heat anti-seize compound that can still be found on the market.
#5
Buy better quality stainless fasteners. If you've ever flown in a commercial airliner, they are held together with stainless fasteners. We routinely buy stainless bolts that are rated at 180ksi tensile strength for aerospace applications. This is better than Grade 8. Totally Stainless (among others) sells high-strength stainless fasteners.
#6
This is what I used. They read F593C on top, at the bottom THE, torqued at factory specs. I elected to use lock washers instead of anti-seize. Hmmm...
Last edited by tru-blue 442; November 17th, 2015 at 07:15 AM.
#7
Lockwashers and anti-seize are not mutually exclusive. You should ALWAYS use anti-seize on stainless fasteners.
#8
Is 316 SS a good choice for exhaust ?
I already used some on my intake, but I dipped the bolt in clean oil as per the manual for torque spec 15 followed up to 35 ft/lbs, should I remove those and coat w anti seize?
What is the best high temp anti seize for use on the exhaust manifolds? I have reg anti seize w copper in silver suspension, idk if that's high temp or not?
#9
Is 316 SS a good choice for exhaust ?
I already used some on my intake, but I dipped the bolt in clean oil as per the manual for torque spec 15 followed up to 35 ft/lbs, should I remove those and coat w anti seize?
What is the best high temp anti seize for use on the exhaust manifolds? I have reg anti seize w copper in silver suspension, idk if that's high temp or not?
I already used some on my intake, but I dipped the bolt in clean oil as per the manual for torque spec 15 followed up to 35 ft/lbs, should I remove those and coat w anti seize?
What is the best high temp anti seize for use on the exhaust manifolds? I have reg anti seize w copper in silver suspension, idk if that's high temp or not?
#10
I would avoid SS bolts if I were you. John Deere uses them on there 8.1L diesel and ford used them on the 6.4L diesel. They can't take the heat and just snap off creating an exhaust leak. Not only that but they seize in the hole and have to be drilled out. I know you had one snap off and almost a second one do the same. But how long were those bolts in there? you were trying to remove them; The SS bolts just snap off by themselves. Just use good automotive grade bolts and anti seize. Jmo
now that motor will likely see 20k miles in 20 years in only summer conditions. I gotta admit half the motivation is the fasteners will not rust on the heads and look like crap after a season
can you give a an in service guess for these failures, i know ford trucks and exhaust manifolds (gas or diesel) have a long acrimonious relationship, my buddy just had to replace both ex manis (gas) (100K) on his f350 not sure if failure was fastener or manifold related.
also not to diesel knowledgable but diesel has higher exhaust temps ?
Tensile strength of 316 stainless is comparable to that of a Grade 5 steel bolt. More than enough for an exhaust system. The anti-seize is to facilitate bolt removal. Permatex sells a high temp anti-seize. The stuff used on O2 sensors typically has glass beads so that even after all the volatiles boil off due to the heat, the glass beads prevent the threads from seizing.
found the permatex stuff
http://www.permatex.com/products-2/p...bricant-detail
permatex ad copy states"Protects metal parts from seizing and galling at temperatures up to 2400°F (1316°C). It is recommended where copper contamination must be avoided, under conditions of extreme pressure and temperature, and with stainless steel, titanium and nickel alloys."
I have the regular copper permatex ill get some of this ordered and MAW redo those intake SS bolts i just dipped in oil.....
#11
I use SS screws on my exhaust manifolds. I haven't had a problem and don't expect to.
As for breaking exhaust manifold screws, the Chrysler/Jeep 4.7 V8 is notorious for breaking exhaust manifold screws (always the ones you can't reach) and warping the heads, and those screws are reg'lar ol' steel.
- Eric
As for breaking exhaust manifold screws, the Chrysler/Jeep 4.7 V8 is notorious for breaking exhaust manifold screws (always the ones you can't reach) and warping the heads, and those screws are reg'lar ol' steel.
- Eric
#12
Stainless does thermally expand 1.5 times as much as carbon steel at a given elevated temperature. Should work fine in the exhaust system though.
My factory Ford carbon steel exhaust manifold studs fatigue failed, had them replaced with ARP stainless 170ksi studs (of course, while the engine was removed at 80k miles). The service writer couldn't understand why I would rather use those than "new Ford parts".
#13
I put stainless bolts on the manifolds on the blue car, and stainless locks/tabs that bend like the original stuff. I bought a cheap stainless kit from ebay and used them for most everything, no problems in 7 years.
I also cleaned and painted new repro Thornton manifolds (Like W & Z or whatever a 1970 442 used). I painted them with Por-15 black satin paint and followed the instructions, clean, paint, let dry, paint again, bake in oven at a certain temp for a certain time, I don't remember. But everything about the manifolds and bolts still look like I bolted them on yesterday. They are beautiful.
Have fun,
I also cleaned and painted new repro Thornton manifolds (Like W & Z or whatever a 1970 442 used). I painted them with Por-15 black satin paint and followed the instructions, clean, paint, let dry, paint again, bake in oven at a certain temp for a certain time, I don't remember. But everything about the manifolds and bolts still look like I bolted them on yesterday. They are beautiful.
Have fun,
#14
I have ordered the Permatex anti seize nickel lubricant for s/s, and plan to pull 1 by 1 and re-torque as I go for the exhaust bolts. Easy peasy while they are out on stands. Better safe than sorry, broken exhaust bolts just suck.
Last edited by tru-blue 442; November 18th, 2015 at 05:25 PM.
#15
hey adam im not saying MAW im just saying SS lock tabs i got these for mine havent got them on yet....i ordered the Ni AS as well
http://www.ebay.com/itm/69-70-71-72-...Ch1dZQ&vxp=mtr
http://www.ebay.com/itm/69-70-71-72-...Ch1dZQ&vxp=mtr
#18
I wouldn't know how to act without the rusty bolts... I generally don't have manifolds, but on my headers I've always used black oxide with no problems. However I have been down in Texas for the last 39 years.
#19
my boss and i were just comiserating about rusty bolts yesterday, we both have summer only cars never any snow salt and little moisture and we have daily drivers as well. a simple job on the summer car can turn into a broken bolt nightmare on a 6+ year old daily driver here in new england. Not to mention snow and ice fighting methods have gotten much more aggressive w pretreating roads and using spray chemicals instead of just sand and salt. I just sold sold my 12yo plow truck ran and drove mint but was so rusty it would not pass state inspection w out major work.
#20
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