Stainless Steel Bolt Kit - Z Car Creations?

[rejracer]

I would not use 304 on the fan mounting, or anything requiring strength. 304 is brittle, and weaker than a class 8.8/grade 5 bolt. Stainless will not take the flexing that a class 8.8 bolt will. For this reason, it's unsuitable for applications requiring long term strength.

 

Either MMS is selling you class A-2 / grade 18-8 or has the specs on non-automotive classed bolts wrong.

 

http://www.ssina.com/view_a_file/fasteners.pdf

 

Actually there is a bit more to it than the above.

304 comes in 3 varieties:

304 Tensile strength: 90ksi ( 1 Ksi is 1000 psi)

304-A Tensile strength: 75ksi

304-SH Tensile strength: 125ksi

 

c 8.8 Tensile strength: 120ksi

c 10.9 Tensile strength: 150ksi (this is class 10.9 for reference)

 

http://www.boltdepot.com/fastener-information/materials-and-grades/bolt-grade-chart.aspx

 

At best, these are weaker than the OE, as I believe the OE fan bolts are class 10.9. It's fine for most the non critical stuff, but I would not use them on the fan mount. There are stainless specification that are stronger than class 10.9, you just have to find the right ones. So don't give up if you're set on stainless. Just beware, the stronger stainless fasteners are extremely expensive.

 

I use a lot of stainless, and the price on this kit is excellent. I think I might buy one, but only if I can get the heads I want. I like the allen drive stainless heads, especially the pan head style, they polish up very well.

 

Happy wrenching.

[Lazeum]

 FYI with car OEM's,  we use grade 10.9 with Zn coating and they hold very well. those are also cheap, no need for stainless since you can get something strong, cheap that can look good  (ie Shinny or black)

Edited November 7, 2010 by Lazeum

[AtlantaZ]

Just a heads up on this kit... it does NOT come with the four intake manifold bolts for a fuel injected intake. I called the vendor and was told that those bolts are not part of the standard kit. I ended up buying these: http://www.jegs.com/i/ARP/070/773-1004/10002/-1?CT=999

[ozzzzz]

Those would be a grade 5 or little bit below ISO grade 8.8. I guess you should be good to go

 

At the same time, I don't know what Nissan was using at that time (I haven't seen anything written on them)...

 

 

 

 

For your info, I was using grade 10.9 on GM vehicle I have been working on.

I believe 10.9 is a metric bolt class not a grade. There is a difference. Just fyi no offense ment. There is a aircraft grade 10

I think it is around 185kpsi range? A friend of mine was using them on a ultralite.

Edited December 10, 2010 by ozzzzz

[Lazeum]

I don't take it as an offense but what would be the difference between a grade and a class? Should we say grade for nuts and class for bolts?

 

bolt class 10.9 means that ultimate strength is min 1000MPa (145ksi) and yield strength is 1000*90% = 900MPa min (130ksi)

 

 

[ozzzzz]

I don't take it as an offense but what would be the difference between a grade and a class? Should we say grade for nuts and class for bolts?

 

bolt class 10.9 means that ultimate strength is min 1000MPa (145ksi) and yield strength is 1000*90% = 900MPa min (130ksi)

 

There is ISO metric class of bolts and there is the SAE grade type(American sizes)also ASTM rating system. It's not just the psi and yield ratings.

you should Google it to get the exact differences.

[Lazeum]

 

There is ISO metric class of bolts and there is the SAE grade type(American sizes)also ASTM rating system. It's not just the psi and yield ratings.

you should Google it to get the exact differences.

Seriously, there isn't much difference. You're being picky with such details

 

 

 

 

 

When you look at Wikipedia (ok, not the most reliable source   

 

The numbers stamped on the head of the bolt are referred to the grade of the bolt used in certain application with the strength of a bolt. High-strength steel bolts usually have a hexagonal head with an ISO strength rating (called property class) stamped on the head. And the absence of marking/number indicates a lower grade bolt with low strength. The property classes most often used are 5.8, 8.8, and 10.9.

 

So if the class is not shown, the grade of the bolt become lower?   

 

 

 

 

Mild steel bolts have property class 4.6. High-strength steel bolts have property class 8.8 or above.

 

The same type of screw or bolt can be made in many different grades of material. For critical high-tensile-strength applications, low-grade bolts may fail, resulting in damage or injury.

 

Based on the last comment, should we consider the grade as "Mild Steel" or "High Strengh Steel"?  So lower grade of steel bolt will have a lower property class ?

 

 

 

 

Metric

 

The international standard for metric screws is defined by ISO 898, specifically ISO 898-1. SAE J1199 and ASTM F568M are two North American metric standards that closely mimic the ISO standard. In case of inch sizes the grade is dictated by the number of radial shapes plus a value of two. Inch-system bolts use integer values to indicate grades but metric bolts use numbers with one decimal. The two North American standards use the same property class markings as defined by ISO 898.[38] The ASTM standard only includes the following property classes from the ISO standard: 4.6, 4.8, 5.8, 8.8, 9.8, 10.9, and 12.9; it also includes two extra property classes: 8.8.3 and 10.9.3.[39] ASTM property classes are to be stamped on the top of screws and it is preferred that the marking is raised.[40]

 

When I read the last quote, seriously, what's the difference?

 

 

 

 

I'm playing the smart ass but I don't feel there's big differences...

 

There're also a lot of humor in my message, don't take it too seriously   

Edited December 11, 2010 by Lazeum

[ozzzzz]

Seriously, there isn't much difference. You're being picky with such details

 

 

 

 

 

When you look at Wikipedia (ok, not the most reliable source   

 

 

 

So if the class is not shown, the grade of the bolt become lower?   

 

 

 

 

 

 

Based on the last comment, should we consider the grade as "Mild Steel" or "High Strengh Steel"?  So lower grade of steel bolt will have a lower property class ?

 

 

 

 

 

 

When I read the last quote, seriously, what's the difference?

 

 

 

 

I'm playing the smart ass but I don't feel there's big differences...

 

There're also a lot of humor in my message, don't take it too seriously   

[rejracer]

I just stumbled across this thread again.

 

The difference between class and grade is like BAR and PSI. It's metric versus imperial.

Grade 5 is the same material as a class 8.8.

Grade 8 is the same material as class 10.9.

Please note they are not the same strength, because the sizes are different.

 

Now for the practical differences:

The diameters are not the same.

The thread pitches will be different.

The markings on the heads are different, Class has the number on the head, Grade has radial lines. 3 lines = grade 5. 5 lines = grade 8

The hex head sizes will be different (as in imperial not metric sizes).

 

The problem is folks are giving advice and they are saying things like, "you need a grade 8 bolt". Then the neophyte goes to the hardware store and buys a class 8.8, because he knows it's metric, and ends up buying a bolt that is "the same" as a grade 5 bolt.

 

If the head is not marked, then it's either grade 2 (which is garbage) or unknown in the metric system.

 

It's not that we are being picky, we are trying to be accurate and to give advice to those that don't know the difference between a metric and an imperial bolt. Fellas chiming in mocking those trying to help out is not doing anyone any favors, especially the guy going to the hardware store buying the wrong fasteners!

 

So in short... 10mm Grade 8 bolts don't exist. Got it?

 

Ever wanted to know what a sex bolt is? Click the link and find out!

http://www.boltdepot.com/fastener-information/

[theramz]

I would not use 304 on the fan mounting, or anything requiring strength. 304 is brittle, and weaker than a class 8.8/grade 5 bolt. Stainless will not take the flexing that a class 8.8 bolt will. For this reason, it's unsuitable for applications requiring long term strength.

 

Either MMS is selling you class A-2 / grade 18-8 or has the specs on non-automotive classed bolts wrong.

 

http://www.ssina.com/view_a_file/fasteners.pdf

 

Actually there is a bit more to it than the above.

304 comes in 3 varieties:

304 Tensile strength: 90ksi ( 1 Ksi is 1000 psi)

304-A Tensile strength: 75ksi

304-SH Tensile strength: 125ksi

 

c 8.8 Tensile strength: 120ksi

c 10.9 Tensile strength: 150ksi (this is class 10.9 for reference)

 

http://www.boltdepot.com/fastener-information/materials-and-grades/bolt-grade-chart.aspx

 

At best, these are weaker than the OE, as I believe the OE fan bolts are class 10.9. It's fine for most the non critical stuff, but I would not use them on the fan mount. There are stainless specification that are stronger than class 10.9, you just have to find the right ones. So don't give up if you're set on stainless. Just beware, the stronger stainless fasteners are extremely expensive.

 

I use a lot of stainless, and the price on this kit is excellent. I think I might buy one, but only if I can get the heads I want. I like the allen drive stainless heads, especially the pan head style, they polish up very well.

 

Happy wrenching.

rejracer is correct. If you use fasteners from a hardware store it's almost sure to be Chinese. Those manifold bolts pictured in the bag have serrated face nuts and lock washers. You cannot get those nuts in grade 10.9, and you never use them with lock washers. They look to be nickel plated low grade steel. As for the stainless they may be okay for holding the covers on but that's it. Have you ever seen an engine bay after the fan comes off at 6k rpm? I always use oem bolts or ARP on critical things.

Some of the larger Napa stores carry bolts for eash purpose. Another source is McMaster sales online catalog for some of the longer bolts on the timing cover. 18-8 stainless is stronger but can cost 3-5 times as much.

[Lazeum]

Strenght is not the only concern. Torque to tighten bolt & their class are linked. You can surely use stronger bolts but torque has to follow.

 

If you take a stronger bolt, torque to make sure nut/bolt won't get loose would have to be higher to stress the thread enough to make sure it still does work.

 

 

 

 

Since the first debate I've purchased a full set of bolts for my Z; I had to order them thru a bolt specialist (the only one I've found, here in Europe with the correct size, pitch, lenght, etc), then I had to find a plating company, make sure they would degas the bolts after the plating to remove H2 to avoid bolts to become brittle, etc. not so easy, it took me tenth of hours to get it.

 

 

[Tony D]

He's right, a 'stronger' bolt needs more torque applied to give the proper preload and keep it from loosening.

 

If the threads you are bolting into aren't up to the task (aluminum without inserts...)then all you did by putting a 'better' bolt on there and keeping the same torque is increase the chance of loosening/fretting... If you torque higher in soft threads, they stretch and deform...or pull out altogether!

 

I have to do a 30 minute presentation on this next Tuesday for our new engineers...curiously this floated to the top of the pond to remind me of that fact. Damnit. So much for free time this weekend...