Can I use these for rear engine mount?

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crassius

Well-Known Member
Sep 30, 2012
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it would depend mostly on what the threads in the motor case look like - if it came out because the threads are bad, then helicoil or a slightly larger bolt would be better

NOTE: most blind holes such as these use studs rather than bolts due to the danger of inserting the bolt too deep & breaking the case
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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Be sure the threads are long enough and they should work fine.
Also be aware, the bolts shown are not high grade.
Take Crassius's advice about bottoming to heart. It's easy to crack a case.
 

crazyinsane51

Member
Apr 2, 2012
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it would depend mostly on what the threads in the motor case look like - if it came out because the threads are bad, then helicoil or a slightly larger bolt would be better

NOTE: most blind holes such as these use studs rather than bolts due to the danger of inserting the bolt too deep & breaking the case

I gotta take my engine off tomorrow to get a better look. I think it just unscrewed itself from the some of the engines vibrations.
 

crazyinsane51

Member
Apr 2, 2012
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Florida
Be sure the threads are long enough and they should work fine.
Also be aware, the bolts shown are not high grade.
Take Crassius's advice about bottoming to heart. It's easy to crack a case.
Yeah I know. Get 8.8 or better. But how good are the ones I listed? Doesn't say does it ?

And I can't see that guide its to small.
 
Last edited:

bairdco

a guy who makes cool bikes
Aug 18, 2009
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living the dream in southern california
if there's an industrial fastener place near you, like Fastenal or something, you can pick up replacement hardware for pennies.

there's a place near me i can replace every bolt on the engine for the same price as those 2 bolts form home depot...
 

2door

Moderator
Staff member
Sep 15, 2008
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I wouldn't rely on quality fasteners from a home improvement store. Typically you'll get lower quality than if you take Bairdco's advice and buy from an industrial supplier. Fastenal, Fasteners Inc, Grainger are some examples.

If I could make a suggestion instead of hex head bolts like those you linked to, look for Allen head capscrews. They allow more space where the head lays against the engine mount clamp/strap. Getting the right length is important but not that difficult.

Above all buy and use a torque wrench. That's your best defense against fastener and case thread failure usually caused by overtightening.

Tom
 

crazyinsane51

Member
Apr 2, 2012
38
0
6
Florida
I wouldn't rely on quality fasteners from a home improvement store. Typically you'll get lower quality than if you take Bairdco's advice and buy from an industrial supplier. Fastenal, Fasteners Inc, Grainger are some examples.

If I could make a suggestion instead of hex head bolts like those you linked to, look for Allen head capscrews. They allow more space where the head lays against the engine mount clamp/strap. Getting the right length is important but not that difficult.

Above all buy and use a torque wrench. That's your best defense against fastener and case thread failure usually caused by overtightening.

Tom
the 1 stud just feel out so good thing it wasn't stuck or anything. Yeah the allen head is smaller but I don't have any allen head sockets for my torque wrench? Maybe I'll get some if I decide to get some allen head bolts. How much torque should it be? 50-70 inch pounds? I kinda looked it but just wanna make sure.
 

2door

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Sep 15, 2008
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50 to 70 is about right for a 6mm fastener. I usually shoot for 60. That's sufficient.
I'm one who doesn't use or recommend thread locking compound (Loctite). However if you want to use it do not use the red type. That is considered a permanent assembly and you'll play heck getting any fastener back out if the need arises.
Use blue or green, never red.

Good luck.

Tom
 

crazyinsane51

Member
Apr 2, 2012
38
0
6
Florida
if there's an industrial fastener place near you, like Fastenal or something, you can pick up replacement hardware for pennies.

there's a place near me i can replace every bolt on the engine for the same price as those 2 bolts form home depot...
I went to Home Depot and Lowes today. They have 8.8 grade hex bolts but the the allen key bolts they had are way to short. And of course that didn't have any studs. I got a Fastenal near me butts kinda out of my way.

I'm looking on Fastenal.com and when I check the stock for the studs they only have these? http://www.fastenal.com/web/product...rtby=wholesaleprice&sortdir=ascending&pageno=

the higher grade ones are further away.
 

crazyinsane51

Member
Apr 2, 2012
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update. I went to fastenal today and they didn't have studs so I just went with M6-1.0 50mm bolts. 60mm was to long. Had to go back. So far so good. I also had an extra clamp from another build I didn't use. But for future reference I will try a U-joint strap if I lose this one.
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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Just buy extra long bolts and cut them to size with a grinder. Be sure to thread a nut on before cutting so when you remove the nut, it will clean up the threads. A little touch up with the grinder and you have studs as long as you need.
I have also simply threaded coupler nuts onto the extra long bolts and tightened the mount down that way.
 

crazyinsane51

Member
Apr 2, 2012
38
0
6
Florida
Just buy extra long bolts and cut them to size with a grinder. Be sure to thread a nut on before cutting so when you remove the nut, it will clean up the threads. A little touch up with the grinder and you have studs as long as you need.
I have also simply threaded coupler nuts onto the extra long bolts and tightened the mount down that way.

nobody had bolts long enough that was fully threaded?