Hey everyone, are the automotive grade bolts from Autozone strong enough to hold motor mounts. I'm putting an ls turbo in an ek. They say category 8 but not grade 8. Is it the same? Also, should I use locktite on them? On the head it says 8 8. Any help would be great.


Modified by scbmx87 at 5:41 PM 10/2/2008

 

Well, I don't know what the requirement is, but the "8 8" on the head is a marking for metric bolt strength. Grade 8 is a US (or more precisely, SAE) marking. And....

This place says that 8.8 bolts aren't as strong as 10.9's.... I would tend to agree. I think that the 10.9's would be much more likely to be engine mount bolts.

Take a look at this chart from the same site:

http://www.boltdepot.com/faste....aspx

Note the 830, 940 and 1040 MPa (that's MegaPascals.) for the strength of the 10.9's - Converts to 120381, 136335, and 150839 psi. Grade 8 US bolts are 120000, 130000, and 150000, so I'd say 10.9's are a better match for grade 8's than 10.9's.

Might be worth getting the upgrade....but not having done it, I'm not really in a position to say.

 

Thanks for the info bud, that was really helpful! Looks like I need me some 10.9s.

 

Probably not a bad idea.... In the long run, bolts are cheap insurance. Glad I could help.

 

SAE Grade 8 is approximately equal to Metric Class 10.9. See sites like https://jdparts.deere.com/part...o.htm

Looking at the prices of some motor mount bolts at an OEM Honda parts site suggests they may actually be SAE Grade 5 ( = ~ Metric Class 8.8). That is, the prices are low enough that they may be the lower strength steel. But I cannot confirm. Suspension bolts are much higher priced, but I am not sure if this is because the suspension bolts are Metric Class 10.9 or because of special features like splines on them.

Still, like Perry and you are thinking, it's best not to gamble. Barring more evidence, I'd buy the 10.9 ones. Two resources for them:

--True Value hardware stores often have Metric 10.9 in open bins. Rarely do they not have the bolt I need when working on my Hondas. Home Depot OTOH has failed me many a time.

--Junkyard. Much cheaper than True Value.

 

I realized that I have about 20 friends with hondas. I got all my bolts, OEM for free! You guys were a huge help, its much appreciated. ONe for each of you!