None Too Thrilled About Torque

[FrizzleFried]

Been getting a vibration. Figured it might be my mount ... might be time to do better than "guessing" how tight to make it. So I pull out the torque wrench... look up stuff and 8mm I read I should be good for up to 175 inch/lbs... with one place suggesting a max of 144 inch/lbs. I figure I want to be safe ... I set my torque wrench for 120 inch/lbs and get at the right stud at the back...

Yeah... stripped it out. Not inside the block but stripped out the friggin threaded post.

Lovely.

Where did I go wrong? Is 120 inch/lbs too much?

The back studs on the Phantom ARE 8mm... right?

WTF... now I guess I get to pull the stud... yay.

 

[Whitewill1412]

Time for a new stud. I'll be right over

 

[FrizzleFried]

I am guessing it went down this way... I'm interested in your opinions...

My hypothesis:

My 'guessing' as far as the cranking down is concerned resulted in a partial thread failure at some point due to (likely) over torqueing. I am a rather larger fellow and I do have a ... ahem ... history ... of being a little over-aggressive with my torqueing simply because... power.



Well... I figure my vibration issue could partially be due to that failure getting a little worse and worse... as when I attempted to torque down it didn't get close to the 120 ft/lbs. EITHER side. BOTH side stripped.

Could be 'crap' nuts? Might behoove me to go get some higher grade ones at the local True-Value...

 

[Whitewill1412]

I would definitely get some better hardware

 

[FrizzleFried]

Welp I just compared the hardware on the bike that came with my original motor with the hardware on the v3 bottom end in the box. The hardware on the bike utilizes a thin-style nut. The hardware on the v3 bottom end is a nice fat nut. I suspect that in-of-itself would have made a difference.

 

[DAMIEN1307]

What I did with my P-85 V-2 was to take out both front and rear mounting studs, measure the correct depth, and replaced them with actual bolts just a hair shorter than the depth I measured so I wouldn't bottom them out through the casing....Best thing I could have done as it brought it down to zero vibration through the frame, at least any that could be felt, and the bolts stay in there rock solid, I have never even had to tighten them in almost 2 years now.

I did this because I had one rear stud just snap off on me while I was riding and I said never again...Gee I love Lowes Hardware store...lol.

 

[ImpulseRocket]

What I did with my P-85 V-2 was to take out both front and rear mounting studs, measure the correct depth, and replaced them with actual bolts just a hair shorter than the depth I measured so I wouldn't bottom them out through the casing....Best thing I could have done as it brought it down to zero vibration through the frame, at least any that could be felt, and the bolts stay in there rock solid, I have never even had to tighten them in almost 2 years now.

I did this because I had one rear stud just snap off on me while I was riding and I said never again...Gee I love Lowes Hardware store...lol.

I did this for all 4. Grade 12.9 cap headed screws. The hardware that comes on the Phantom didn't impress me, so it all got upgraded.

Grade 10.9 will work more than adequately, by the way. I just went off the deep end a hair.

 

[FrizzleFried]

....what was the correct depth? Did either of you record said info?

 

[DAMIEN1307]

....what was the correct depth? Did either of you record said info?

Nope...I just used an existing stud, screwed it in, marked it with a black magic marker as to how far in it was, and then took it down to Lowes hardware and matched the appropriate thread, length, depth, etc. with what I call grade 8 bolts, except it was the metric equivalent.

I didn't get fancy with writing down specs or exact measurements when I could easily just do what I did and match them up.

Don't forget the lock washers and take that into account on the depth as well...lol.

 

[ImpulseRocket]

....what was the correct depth? Did either of you record said info?

Measure?


No, I didn't record it either. I suspect no two are the same anyway. I usednthe ultra high tech method of using a bit of wire and shoving it down the hole, then matching it roughly with a bolt I knew would fit.