using stainless steel fastners ?

[mosquito13]

ok my engine came sano lots of fastners. so purchased a complete engine set . big money for bolts when if i know the specs a friend who works at a nut and bolt place will get em for me. so found a complete s/s kit on ebay at a reasonable price. the sheet included (see attachment) has adjusted torque specs. . if i go with all s/s and follow their torque specs not the specs(for grade 8's) in my rebuild manual am i going to be ok ? or should i go with my origanal plan of using the s/s kit as a guide to getting the grade 8's from my buddy ? should add schumaker provided fastners for the headers which i will use regardles.

 

[jessipup]

They are right be real careful with the stainless It will gall up and then there is all kinds of trouble.

 

[Cranky]

They are right be real careful with the stainless It will gall up and then there is all kinds of trouble.

Stainless on stainless is a major problem....for example, a ss nut on a ss stud. That will gall in a heartbeat but going into cast iron isn't too much of a problem.

 

[lewtot184]

stainless bolts have a low tensile strength. they are not a suitable substitute for main, head, and intake bolts. i wouldn't use them for anything but some type of corrosion resistance application. stainless screws with stainless nuts ain't happy, especially with heat.

 

[Cranky]

stainless bolts have a low tensile strength. they are not a suitable substitute for main, head, and intake bolts. i wouldn't use them for anything but some type of corrosion resistance application. stainless screws with stainless nuts ain't happy, especially with heat.

SS isn't that low in tensile strength depending on the alloy. It may be low for the stuff that's being sold for automotive use but for example 316 isn't that low. And the petrochem industry uses SS in lot of applications that require good holding power. As for holding an intake down, I would think even the lower grades would work fine.
http://www.upmet.com/316-mechanical.shtml

 

[Photon440]

While the most common stainless bolts are only as strong as a grade 5 equivilant, you can get better if you want it. There are lots of alloys of stainless being used for fasteners. These ones, for example, claim better than grade 8 strength.
http://www.mmsacc-stainless.com/html/hi_strength_bolts.htm

Stainless fasteners can be polished to look like chrome and stay shiny without rusting, so I can see the appeal.

-=Photon440=-

 

[Cranky]

17-4 is good stuff and you will pay big money for it! I like the machinability of it too. It's not that easy but very doable if you know what you are doing.....but drilling it is another story! Some places use it to make pump shafts. It's also magnetic.

 

[lewtot184]

SS isn't that low in tensile strength depending on the alloy. It may be low for the stuff that's being sold for automotive use but for example 316 isn't that low. And the petrochem industry uses SS in lot of applications that require good holding power. As for holding an intake down, I would think even the lower grades would work fine.
http://www.upmet.com/316-mechanical.shtml

i worked for a pharmaceutical company for 31 years as a sheet metal worker. 99% of my work was with 300 series stainless steels. the 18-8 screws listed by the op are 300 series. they have a tensile/yield less than a grade 5 and close to a grade 3 hardware bolt. there are some 400 series stainless that are much stronger and hardenable but why chase it when 175,000psi-190,000psi fasteners are readily available. i went thru this excercise many years and the correct answer is NO.

 

[mosquito13]

thanks for all the advice

gave the set to my bud , to use as a template to get the right grade 8's, at his nutz and boltz place. they are nice and shinny though.

 

[snakeoil24]

Stainless bolts are a gimmick. They loosen up easily and stretch is not good like a traditional bolt.

 

[Cranky]

i worked for a pharmaceutical company for 31 years as a sheet metal worker. 99% of my work was with 300 series stainless steels. the 18-8 screws listed by the op are 300 series. they have a tensile/yield less than a grade 5 and close to a grade 3 hardware bolt. there are some 400 series stainless that are much stronger and hardenable but why chase it when 175,000psi-190,000psi fasteners are readily available. i went thru this excercise many years and the correct answer is NO.

You are right about the tensile strength being low but 300 series is plenty good for an intake and they take the heat....and I'm a retired 30 year machinist that has machined SS's for most of that time. I wouldn't use SS for anything that needed grade 8 but an intake doesn't really need a grade 5 either....:headbang:

 

[1moreproject]

These days it’s hard to tell where bolts come from or if they comply with recognized standards but if made to spec, 18-8 SS bolts are a little better than Grade 2, although not much. That said, bolts made from chilled butter would probably work for most everything except the rods, mains, and heads. Like Cranky said, stainless should be fine for an intake and probably most other external bolting.

 

[Sixer]

For important stuff, give me ARP or give me death.

 

[bm02tj]

ARP designs their hardware around needed strength and expansion to the metal it is clamping grade 8 bolts are use in all the wrong places

 

[Photon440]

These days it’s hard to tell where bolts come from or if they comply with recognized standards but if made to spec, 18-8 SS bolts are a little better than Grade 2, although not much. That said, bolts made from chilled butter would probably work for most everything except the rods, mains, and heads. Like Cranky said, stainless should be fine for an intake and probably most other external bolting.

These 'chilled butter' bolts you speak of would be all I need for bolting my bacon to the baked potato.

 

[scotts74birds]

I've seen some real crap out there in stainless. I would not use it for anything internally, and few things externally, unless you know the source of it.