News: stainless bolts

[69vert]

has anyone ever heard that you should not use stainless bolts in alimunum such as intake manifold bolts to head

 

[oceangal]

I found this...

http://www.britbike.com/ubb/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=51;t=001594;p=1

 

[TimAT]

I have to agree with some of that- A plain old bolt in aluminum will corrode and seize. I always use anti-seize on stuff like t'stat housings.

I attended a class at Boeing Aircraft about corrosion- There is a table that lists common metals and their resistance to corrosion. I've got a copy of it at home- When I fnd it I'll get it posted. Interesting stuff.

Stainless IS a better choice in aluminum- the galvanic action between the stainless and aluminum is less than between steel and aluminum.

 

[JohnZ]

You should ALWAYS use anti-seize on stainless bolts, regardless whether they're threaded into steel, iron, or aluminum. What's more important is to know exactly what kind of stainless bolt you have - almost all of the pretty-shiny dress-up stainless bolts are Grade 2, about what you'd use to hang a farm gate with. Never use stainless bolts for critical applications like steering, suspension, or brakes unless they're from fastener specialists like ARP, SPS, etc. and are specifically rated at 160,000 psi tensile strength or better.

 

[floopcom]

I am a certified outboard mechanic. Outboards use mostly stainless bolts and screws to hold mostly aluminum pieces together. A typical 316 SS bolt is near grade 5 quality. For 316 SS on aluminum it is important to have clean threads and to use an anti-seize compound, as well as a torque wrench. For 316 SS and aluminum I use a nickel/molybdenum anti-seize called N5000, which I discovered in my other job as a power plant tech. I would not use a copper based anti-seize.

I use 316 SS allen head machine screws on my aluminum intake manifold on my C3. They are easy to install and remove and they look nice. I've never had a problem.

 

[69vert]

S/S bolts

thanks for your input I will look for thw anti sieze you mentioned

 

[floopcom]

Both Fel-Pro and Loctite make an N5000 anti-seize.

From the Fel-Pro site:

"TYPICAL APPLICATIONS
· Bolts, studs, valves, pipe fittings, slip fits and press fits in
nuclear electric power generating plants, chemical plants,
pharmaceutical plants, paper mills and other locations
where stainless steel fasteners are used.
Operational Benefits:
· During assembly - prevents high friction, galling and
seizing.
· Promotes uniform and predictable clamping.
· During operation - high purity prevents stress corrosion
· Disassembly - prevents seizing, galling, destruction of
threads
DIRECTIONS FOR USE
1. Before or during assembly, wipe brush onto threads and
other joint surfaces needing protection.
2. Use full strength. Do not thin."

I'd been told it contained Molybdenum, but the MSDS sheet says it does not. I've had very good luck with it. It's pricey at $45 for 8 ounces, but 8 ounces will last years and it never deteriorates.