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HybridZ

Bolts/screws/etc


Z0wner

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As I am pulling apart my Z, I have noticed that many of the bolts/screws/nuts are in horrible condition. A lot of them probably shouldn't go back into the vehicle. Here is my question, is there a place that lists the sizes/thread/grade of the bolts/screws that are in the Z? Is there a place where one could purchase these bolts/screws?

 

I was just curious, as many of the screws i'm taking off are snapping (even though drenched in wd-40)

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I was also on a mission to find a "list" of sizes and thread specs. I found it much easier to buy one of those little plastic bolt mearuing devices ( what the heck is the right name...?) Anyways, the sell them at hardware stores usually next to the nuts and bolts. The will easily measure bolt sizes and threads. And yes, I found most everything I need at ACE Hardware. Also, here is a link to some fancy stuff:

 

http://stores.ebay.com/Restoration-Stainless

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Shopping for nuts and bolts at a local hardware store can be risky. I have often seen cad plated bolts in the grade 8 bin with grade 5 markings on the head. I have also seen bolts marked with the metric grade 10.9 and the grade 8 hash marks (which is it and why did the Chinese dual mark the bolt?). An industrial hardware store is probably a better choice. McFadden-Dale here in SoCal and you can always use McMaster-Carr (http://www.mcmaster.com).

 

You can also still get most of the OEM nuts and bolts directly from Nissan or MSA.

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You can get a size checker just about any place. Another way is to go to True Value or Lowes and buy one of every metric bolt and nut they have. Organize them so you'll be able to tell the size and use those as a size checker. That actually works well. They have a sizing chart hanging in the hardware area of Lowes that should give you a good idea, it has nuts and bolts so you can figure out what size you need. Saves a lot of frustration.

 

- Joe

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Make sure for bolts that need strength,get grade 8 for standard,10.9 for metric.Stainless are rated like a grade6 or maybe even weaker.Your local Ace hardware has a wide selection.Believe me I know.:)

This is not a good rule to follow.

First of all an SAE grade 8 is a metric 12.9. An SAE grade 5 is a metric 8.8. The metric 10.9 falls between them.

Secondly - bolt grade also determines the required "stretch" to get the bolt to seat (grip) properly. If the original bolt was a metric 8.8 and you replace with an SAE grade 8 a much higher torque will be required to seat the bolt properly and you risk stripping the threads in the mating part. If you torque ian SAE grade 8 to the original bolt torque that was a metric 8.8 it will not stretch properly and will come loose.

Third - stainless bolts are rated the same way alloy bolts are rated - that's what those funny marks on the bolt heads are for.

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Stainless steel fasteners are a crapshoot. The advantage of stainless steel fasteners is the ability to resist corrosion and heat. Common stainless steel alloys used in fasteners are 304, 302HQ, 315, and a few others. These alloys have good corrosion resistance, but are not heat treatable. Tensile strength is typically around 85 ksi and can be made up to 140ksi (just below Grade 8 ). Other, more exotic stainless steels can have tensile strengths of up to 170 ksi. (beyond Grade 8 ) but they are double and triple the price of a medium carbon steel bolt.

 

I wouldn't trust a stainless steel fastener in any critical application unless I bought it from ARP or an industrial supply house that verified its strength rating. Nothing stainless from ACE, True Value, Home Depot, Lowes, etc. would go into any important suspension or engine part on my or my customer's cars.

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John,

 

That's where even more trouble can occur. If you go to an Unbrako catalog you'll see that their Grade 8 bolts are rated at 190ksi tensile and 170ksi yield which is even higher than the metric 12.9's made by Textron. This would yet be another opportunity for a loose or overstreatched bolt. This is why I recommended against arbitrarily going to higher strength bolts. If you don't do your research, "a good idea", can open up a whole can of worms.

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One has to consider the function of the bolt, as well. A lower grade bolt will have little negative impact if, say, used on a fender (where the bolt sees little load). It would be a bad idea to use the same, low grade, bolt on your flywheel or suspension components. A properly torqued/seated fastener has several forces acting upon it.

 

A bolt that see's little, or no, shear loading (the fender bolt) has 2 basic forces acting upon it:

1) Tensile (along the bolt's axis)

2) Torsional (about the bolt axis)

 

A bolt that see's a good amount of shear loading (the flywheel bolt) has 3 basic forces acting upon it:

1) Tensile

2) Torsional

3) Shear (perpendicular to the bolt axis)

 

The flywheel example, as it pertains to shear loading, is a bit of an oversimplification as the shear load between the crankshaft and flywheel is generally carried by dowel pins and by the friction between the two components (if properly fastened). But one can see that there are many forces that act, or potentially could act, upon a bolt... therefore driving bolt requirements.

 

*Edit*

Sorry guys... just put this 'in addition' to the discussion of grade types and yield strengths!

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This is some good information. Glad that it has gotten so many replys...

 

As for me, seeing that they sell them in a kit, is probably what I'll end up doing. This will ensure that every bolt/nut/screw fits as it should, and for the price it makes it worth doing as opposed to possibly using crummy old screws that I have pulled from the vehicle. About going to ace, I probably will take a look into that, as it is probably the cheapest way to acquire pieces

 

http://stores.ebay.com/Restoration-Stainless -thanks jaime

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boy I feel like an idiot!:banghead: ,I suppose I should do a little more research.I was just saying for arguments sake,for heavy duty uses,suspension,motor mount bolts,etc.if you go with standard sizes grade 8,metric grade 10.9 minimum.say fender bolts,window washer bottle bracket,etc stainless would be ok.I've always thought that was a basic standard to go by.Question;does coarse thread have any strength pros or cons against fine threads?

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