Stainless steel bolt kits.

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gilberttitan08

gilberttitan08

Mexican Hillbilly!!!
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hey guys I’m tempted on buying a stainless bolt kit, for SB. But my concern is, doesn’t stainless steel seize up within time?
 
I tied to have one look pretty with stainless bolts but most are Grade 1 and just don't do a good job IMHO.
 
I hope not, they are all over my engine in low stress applications!!!:lol:
 
gilberttitan08 said:
hey guys I’m tempted on buying a stainless bolt kit, for SB. But my concern is, doesn’t stainless steel seize up within time?
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in my experience, generally, SS fasteners are kind of "gummy", so they can gall up if you don't use a dab of anti-seize on the threads. I agree they are more useful in low torque situations, like valve covers, intake manifold, etc
 
rustycowll69 said:
in my experience, generally, SS fasteners are kind of "gummy", so they can gall up if you don't use a dab of anti-seize on the threads. I agree they are more useful in low torque situations, like valve covers, intake manifold, etc
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I was thinking like alternator brackets, pulleys, power steering pulleys, I’m very interested in this CVF serpentine kit. The kit comes with stainless steel bolts.
 
When I restored my 69 Barracuda for the second time, I did not want to go back to the turquoise engine in the F8 green engine bay. So I painted the engine with Eastwood's Gloss black engine paint and used all stainless fasteners. I used a little anti seize on each bolt. No problems after 5 years.

Cuda43.JPG
 
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Well, I just had the pleasure of the dreadful galling of a SS bolt and a cast aluminum water pump. The head snapped off, I tried drilling to use an EZ-Out with the pump still in my 2007 5.7 MegaCab. That didn’t work.... Ultimately I removed the pump from the engine and was able to completely drill out the bolt and retap the M8X1.25 threads. Total time to repair this was 8 hours..... Typically I use White Lithium grease on most of my bolts. I’m gonna use Anti-Seize on this particular application :BangHead:
 
SS is generally more brittle, and indeed will gall. Really no good reason to use them in an engine. And 304 is one the lesser grades, when it comes to not corroding. Regular medium carbon steel bolts has all the advantages as fasteners in this application.
 
Bolt strength is measured by tensile strength in psi ( pounds per square inch). Grade 5 120,000 psi, grade 8 150,000 psi, 18-8 and 316 stainless steel 70,000 psi, high strength 316 socket head cap screws are 110,000 psi, 17-4 stainless steel 130,000 psi. Stainless steel on stainless steel will indeed gall and weld itself together if anti-seize is not used. But typically not to other metals. Aluminum is nasty since when it corrodes it expands something like 100 times and absolutely locks fasteners up. After working on underwater stuff, I use anti-seize on every threaded connection except critical fasteners such as rod bolts/nuts, head bolts, main bolts.
 
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Great tech info listed in the above posts. My M8X1.25 (slightly larger than a 1/4X20 bolt) 304 SS bolt that was holding a ProCharger bracket is the bolt that snapped. It would be the bolt located at the bottom of the pic, so there’s quite a bit of leverage and force on a relatively small diameter bolt. It snapped the second I put minimal pressure on the Allen Key to remove it.
Ultimately it’s a bad combination of a brittle SS bolt and galling of the cast aluminum
 
300 series stainless doesn't harden through heat-treating. It work hardens, meaning as you bend or deform the material it will harden up. 304 is not very hard. 316 is harder.
300 series isn't 'brittle', but as it work hardens from deformation it will fail in a brittle manner.
The other thing with stainless is that it can pit and erode when in an oxygen free environment. Think threads, or mating surfaces of two parts bolted together. Having parts pre-passivated (acid treated to pre-oxidize the surface) can help, but as threads engage they can scratch and remove the 'white layer' that provides the corrosion resistance and then galvanic action can attack the threads. Most hardware comes passivated.

Really hard to beat tempered alloy steel bolts for strength (most blackened hardware, including socket head cap screws).
 
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