[zbhover]

Hello everyone, I'm working on cleaning up our 350 for our V8 Beetle project and I was wondering what was the best stainless bolts to be using for the engine?

I figured that I'd replace as many of the ones that can be seen as possible just to keep the engine looking a little cleaner. I figured the intake, valve covers, power steering pump, alt., etc.... Maybe I'll do the oil and tranny pan bolts too just to keep them from getting all rusty from road grim, etc....

So what grade of stainless is best to use for this??? I've seen a couple kits on ebay with 304 ss bolts, but I figured I'd just order my own bolts from McMaster Carr. I'd also like to stick with cap screws rather than socket head.

Looking at Mcmaster it looks like they just have 300, 316, 17-4PH, and 18-8 but they don't have 304.

Just for figuring prices I was looking at 1" x 1/4-20 bolts:
17-4ph is like $7 a bolt so thats out.
18-8 is $10.16 for 50 bolts
300 is $10.81 for 10 bolts
316 is $12.09 for 25 bolts

According to McMaster 316 is better for corosion resistance than the 18-8 and the 300 is military spec.....

Would going for the middle grade (316) Be alright????

I'm just don't want the bolts to get all rusty a few years down the road, but I also want them to be strong enough......

Also is there another supplier for ss bolts that might be cheaper than mcmaster or have something better????


Thanks for your help....

[ScoTFrenzel]

I want something at least equivalent to a grade 5 for alt, ps, wp, intake, etc.
For non structural stuff, like pans, any will work. It is a stress free environment.
I use only grade 8 stuff in structural components.
Inside engines either factory or ARP only.

Any steering/suspension components in stainless MUST be THE BEST $$$$.

Right now I am not trusting any bolts made in China, period. and I am not very enthusiastic about the rod bolts that come in rods but others have not complained yet.

You will have to ask the manufacturer about psi ratings and their grade equivalent.
Buying a prepackaged kit from Jegs or Summit might be fine for all the pans, headers, etc.

[DanielC]

The 17-4 PH, and the 18-8 are stainless steel types used in internal engine structural parts for aircraft and ground based turbines. The PH means that is is a heat treatable metal, and after heat treating they are extremely strong. I used to work at an investment (lost wax process) casting foundry that used these metals a lot.

[XNTRCI-T]

Don't use stainless where the critical load is in tension. SS stretches in tension and loosens quickly. I found out the hard way... I used SS bolts on my steering box, torqued to spec. Within a few hundred miles the steering box was flopping around and I was bouncing off the guard rail on the freeway Fortunately, no serious damage.

[machine shop tom]

There is good information in this link:

http://www.enginebuildermag.com/Arti...ner_facts.aspx

Scroll down to the section titled "Materials".

tom

[powerrodsmike]

What they all said. There is a company called Totally Stainless
that sells high strength ss bolts, supposedly as strong as grade 8.

Don't go cheap, strong SS costs alot.

Mcmaster Carr lists the tensile strength of all of their fasteners, compare the tensile strength of the SS bolt you want to a steel grade 5 or 8 .

From my Mc master's catalog...
Grade 8 alloy steel is 150000 psi
Grade 5 is 120000 psi
316 SS is 70000 psi.
18-8 is 70000 psi

Some of the 316 metric screws are rated higher, 100000 psi

You need to compare the screws you are actually going to use.



Later, mikey

[Stroke]

Ever heard of ARP?

Inside engines either factory or ARP only.

SPS CARR, or 'other' exotics have been used with much success in extreme cases. I once saw a guy buy a 5.0 Ford from a guy and when he toreit down to inspect found it had a grade 5 type hardware nut on the rod bolt. Imagine that!

[powerrodsmike]

Originally Posted by Stroke

Ever heard of ARP?

Buying prepackaged kits takes all the fun out of it... And you don't learn about the little details either.

Later, mikey

[dawg]

I used 316 on my intake-waterpump etc.
never had an issue.

[Stroke]

Buying prepackaged kits takes all the fun out of it

With ARP you know exactly what you are getting. No guessing and wasting time pretending to be a fab-man. What's so fun about scrounging around for something that comes 'prepackaged'? Are the loose nuts and bolts that much fun? I have other things to do, constructive things, instead of wasting my life looking for something that is made specifically for the purpose of this topic -

Stainless Steel Engine bolts?

[joe_padavano]

Originally Posted by powerrodsmike

What they all said. There is a company called Totally Stainless
that sells high strength ss bolts, supposedly as strong as grade 8.

Don't go cheap, strong SS costs alot.

Mcmaster Carr lists the tensile strength of all of their fasteners, compare the tensile strength of the SS bolt you want to a steel grade 5 or 8 .

From my Mc master's catalog...
Grade 8 alloy steel is 150000 psi
Grade 5 is 120000 psi
316 SS is 70000 psi.
18-8 is 70000 psi

Some of the 316 metric screws are rated higher, 100000 psi

You need to compare the screws you are actually going to use.



Later, mikey

17-4 PH has a 180,000 psi tensile strength. We use these fasteners regularly in aerospace applications. Other stainless has lower properties, as you have noted. This is why the stronger bolts are more expensive. If you have an application with Grade 8 bolts currently, DO NOT use anything with a lower tensile strength. As for the discussion about stainless loosening on a steering box, this is either because the bolts used had too low a yield strength or locking nuts were not used.

The rated strengths (tensile yield, ultimate, and shear) as well as the stiffness of metals are all listed in MIL-HDBK-5, which is available on line.

[joe_padavano]

Originally Posted by Stroke

With ARP you know exactly what you are getting. No guessing and wasting time pretending to be a fab-man. What's so fun about scrounging around for something that comes 'prepackaged'? Are the loose nuts and bolts that much fun? I have other things to do, constructive things, instead of wasting my life looking for something that is made specifically for the purpose of this topic -

Some people have more time, some have more money. In addition, not everyone is building a Camaro with an SBC - try finding prepackaged kits for a 64 Olds Jetstar 88 with a lot of one-year-only features. And some of us really do enjoy just doing stuff for ourselves. Either approach is fine if the person doing it is satisfied.

[powerrodsmike]

Joe P- Is this a good online source for the Mil spec 5 handbook ?
http://www.grantadesign.com/userarea/mil/mil5.htm

It seems to have a wealth of information about materials, the processes involved in different treatments, and explanations of the various terms used .

Later, mikey

[joe_padavano]

Originally Posted by powerrodsmike

Joe P- Is this a good online source for the Mil spec 5 handbook ?
http://www.grantadesign.com/userarea/mil/mil5.htm

It seems to have a wealth of information about materials, the processes involved in different treatments, and explanations of the various terms used .

Later, mikey

I hadn't seen that site before, but it looks fine. I have a PDF version of the whole document that I downloaded from a DoD site. Very little changes from rev-to-rev, so using a prior version is fine, particularly for the kind of things we do on cars. Now, for aerospace work, we try to get the latest version, just in case.

There is also MIL-HDBK-17, which covers non-metallic materials, including graphite, fiberglass, and kevlar. That data DOES change fairly rapidly, so you do want to find the latest version.

[oldbogie]

Originally Posted by zbhover

Hello everyone, I'm working on cleaning up our 350 for our V8 Beetle project and I was wondering what was the best stainless bolts to be using for the engine?

I figured that I'd replace as many of the ones that can be seen as possible just to keep the engine looking a little cleaner. I figured the intake, valve covers, power steering pump, alt., etc.... Maybe I'll do the oil and tranny pan bolts too just to keep them from getting all rusty from road grim, etc....

So what grade of stainless is best to use for this??? I've seen a couple kits on ebay with 304 ss bolts, but I figured I'd just order my own bolts from McMaster Carr. I'd also like to stick with cap screws rather than socket head.

Looking at Mcmaster it looks like they just have 300, 316, 17-4PH, and 18-8 but they don't have 304.

Just for figuring prices I was looking at 1" x 1/4-20 bolts:
17-4ph is like $7 a bolt so thats out.
18-8 is $10.16 for 50 bolts
300 is $10.81 for 10 bolts
316 is $12.09 for 25 bolts

According to McMaster 316 is better for corosion resistance than the 18-8 and the 300 is military spec.....

Would going for the middle grade (316) Be alright????

I'm just don't want the bolts to get all rusty a few years down the road, but I also want them to be strong enough......

Also is there another supplier for ss bolts that might be cheaper than mcmaster or have something better????


Thanks for your help....

18.8 is the same as T304. It needs to be remembered that stainless fasteners are rated in corrosion resistance, not strength. Typically a good high strength stainless is about equal to a grade 5 bolt.

Stainless tends to gall when the threads are run into anything, but especially aluminum and other stainless. This increases the friction within the threads and gives a false high side torque reading when bolting things together. It's a darn good idea to always use anti-seize or Loc-tite in the threads, this gives a more representative reading between torque values and actual clamping force and in the case of Loc-Tite helps prevent vibration from loosening the fastener.

For the most part, stainless is perfectly suitable for engine exterior use where the loads are reasonably low and the need for corrosion protection and looks is high. Actually in this case the use of polished stainless is probably superior to chrome plated alloy steel as the plating process significantly weakens steel thru hydrogen embrittlement as H2 is taken up from the chromic acid bath into the steel during the plating process.

ARP and Totally Stainless are two good sources of high strength or at least known strength stainless. Stainless from the home improvement center is probably made in China and is of both dubious corrosion resistance and strength.

Bogie