Bolt-$13, Using Hardness Tester at Work-Free, Knowing What Bolt This Is-Priceless

[TorqSpeed5252]

The results are in and it looks like this is a Grade 8 (10.9) M14 x 2 hex Flange Screw. That's almost about as strong as it gets. Only a grade 9 (12.9) is stronger.

I took 3 measurements at 12 o'clock, 3', 6', and 9' for a total of twelve. In the attached Excel file, 'A' is about 1/4" from the bottom of the bolt head, 'B' is 1/2" and 'C' is about 3/4"

Threw out the highest and lowest values and averaged the remaining ten to come up with an average hardness of 34.4

I guess I have to trust Mazda when they say the bolt is strong enough, as Automotive Engineers are far better men than I. I just wish there was more than one bolt holding my engine in place.

A couple notes,

1. The bolt appears to be custom made as the threads were rolled after the washers were slid on in order to capture them.

2. There are two washers on this bolt.

3. The part number is 9YA02-1437

4. If you have access to a hardness tester don't pull your bolt, test it, and reuse it, as testing the bolt makes ever so small marks on it which whill act as stress concentrations when reinstalled.

5. Does anyone know where I can get a shop/repair manual for this car?

 

[Boother]

I am still unsure why everyone is so worried about only using the single bolt on the one mount. There are only two bolts holding 400+ hp and 400+ ft-lbs LS engines in cars.....

Thanks for taking your time and money to test the ZoomZoom engineers capabilities.

 

[Rotus8]

Manuals are available here, and from other vendors.
http://www.trademotion.com/partloca...catalogid=4778&siteid=214264&categoryID=92290

 

[tsunami]

huh it already is a grade 8... i remember some thread i told some one to put a grade 8 in there oh well... if its breaking a grade 8 its b/c it has loosened up and there is a lot more side stress on the bolt i can't see a tightened bolt breaking at all...


thanks for the info!!

 

[TheMAN]

I have seen metric class 13 bolts on toyotas... so they're even stronger

 

[desperado-c]

huh it already is a grade 8... i remember some thread i told some one to put a grade 8 in there oh well... if its breaking a grade 8 its b/c it has loosened up and there is a lot more side stress on the bolt i can't see a tightened bolt breaking at all...


thanks for the info!!

Has anybody really had a bolt shear off? I thought they were just backing out and then maybe stripping threads or some such.

 

[itzl0l]

^^^ they shear after they back off i think