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  #11  
Old 03-23-2018, 10:28 AM
control control is offline
 
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Thanx, for the first time I will be able to use my big torque wrench for the build.
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  #12  
Old 03-23-2018, 11:00 AM
Aluminum Aluminum is offline
 
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Location: San Jose, CA
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Another thing to worry about: most "clicker" torque wrenches have high inaccuracy near the ends of their range, even when freshly calibrated.

I find these little doodads to be superior in convenience, usability and accuracy:

ACDelco ARM602-3 3/8 Digital Torque Adapter (3-59 ft-lbs) with Audible Alert

Throw one of those and a set of adapters in your tool bag and you'll be able to retorque things accurately with just duct tape and a broom handle.
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  #13  
Old 03-23-2018, 08:23 PM
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vernon smith vernon smith is offline
 
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If you want to get really anal retentive about it you measure the amount of bolt elongation. Not practical on any level but that is how the Double A Fuel dragster guys torque their connection rod bolts. Apparently it removes all the variables associated with metallurgy, lubrication and alignment. I'm sure others will have a different idea

Since they are getting in excess of six grand of horse power from five hundred cubic inches, the stress levels they are dealing with are astronomical. Remember, con-rod bolts are in tension.
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  #14  
Old 03-23-2018, 09:43 PM
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johnbright johnbright is offline
 
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Quote:
Originally Posted by vernon smith View Post
... .measure the amount of bolt elongation... not practical on any level but that is how the Double A Fuel dragster guys torque their connection rod bolts...
It's off topic. Short answer is torque to Vans / AC 43.13 values for AN bolt in tension.

Important thing about connecting rod bolts is, properly torqued, bolt load does not vary as the crank rotates! An under-torqued bolt will fail in fatigue. Bolt tension is the goal and elongation is a better measure because of friction variation in threads and nut face.
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  #15  
Old 03-24-2018, 10:27 AM
EXflyer EXflyer is offline
 
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Quote:
Originally Posted by vernon smith View Post
If you want to get really anal retentive about it you measure the amount of bolt elongation. Not practical on any level but that is how the Double A Fuel dragster guys torque their connection rod bolts. Apparently it removes all the variables associated with metallurgy, lubrication and alignment. I'm sure others will have a different idea

Since they are getting in excess of six grand of horse power from five hundred cubic inches, the stress levels they are dealing with are astronomical. Remember, con-rod bolts are in tension.
Going to A&E school way back we had to torque the main rod connecting bolt on a radial engine, 2800?, it required you use a mic to check it with in other words length. Side note, many truck drivers think that there wheel studs fail due to over torque of them, its more likely under torque I have found. Just something from a grey hair mechanic.
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  #16  
Old 03-24-2018, 10:37 AM
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az_gila az_gila is offline
 
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Location: 57AZ - NW Tucson area
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Smile Just like the dragster...

Quote:
Originally Posted by vernon smith View Post
If you want to get really anal retentive about it you measure the amount of bolt elongation. Not practical on any level but that is how the Double A Fuel dragster guys torque their connection rod bolts. Apparently it removes all the variables associated with metallurgy, lubrication and alignment. I'm sure others will have a different idea

Since they are getting in excess of six grand of horse power from five hundred cubic inches, the stress levels they are dealing with are astronomical. Remember, con-rod bolts are in tension.
Some Lycoming connecting rod bolts are specified that way - labeled as "stretch" rather than "torque" bolts.

https://www.lycoming.com/sites/defau...%20%281%29.pdf
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  #17  
Old 03-24-2018, 01:02 PM
control control is offline
 
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Got my bolt hole-castle nut lined up on all four attachments with a torque of between 51 and 52Nm.

(Specs say at least 450 in/lbs / 37.5 ft/lbs / 50.85Nm so I started with 51Nm and increased to 52 if the bolt needed a little more turning)
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  #18  
Old 03-24-2018, 03:53 PM
MED MED is online now
 
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[quote=control;1248315] Got my bolt hole-castle nut lined up on all four attachments with a torque of between 51 and 52Nm.

My RV-14A does not use castle nuts for the engine mount bolts. Does the RV-14? I know other RVs (7 and 8) also use castle nuts. Anyone know why the difference?
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  #19  
Old 03-24-2018, 05:55 PM
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az_gila az_gila is offline
 
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[quote=MED;1248344]
Quote:
Originally Posted by control View Post
Got my bolt hole-castle nut lined up on all four attachments with a torque of between 51 and 52Nm.

My RV-14A does not use castle nuts for the engine mount bolts. Does the RV-14? I know other RVs (7 and 8) also use castle nuts. Anyone know why the difference?
Interesting change on the latest kit. I used metal self-locking nuts on my -6A since that is what called for on my certified Tiger's O-360.

Much easier to install and they haven't moved yet on either plane,.
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  #20  
Old 03-24-2018, 09:47 PM
n982sx n982sx is offline
 
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Location: Chicago, IL
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Default Confusing thread

I think this thread may be getting into the weeds.

People seems to be addressing two different sets of bolts

The 14 uses AN6 bolts - and locking nuts - to mount the engine mount to the fuselage.

It uses AN7 bolts - and castle nuts - to mount the engine onto the engine mount.

Then again, maybe I was the only one confused.
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