Original vs Reproduction Con Rod Nuts and Loctite

marshg246 said:
Don't know, but I have three (so I can always use middle of the range) 1/4 drive, 3/8 drive, and 1/2 drive. Always stored on the lowest setting per the manufacturer and always in their case and always in my climate-controlled shop. 1/4 checked against 3/8. 3/8 checked against 1/2. 1/2 checked against two old bar types.

Checked at least yearly and calibration checked about every 5 years. Way more calibrated than my arms that are becoming weaker and weaker!
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I've an old Snap-on click type which I scrounged from work - it was being chucked out since it was not possible to lock the torque setting on the assembly line. It's 45+ years old, and looks rather battered, but whenever I check it against a beam-type and with a fishing scale, it seems accurate enough. Rather surprised, though it's always kept on the lowest setting in my toolbox. No case though, and no climate control either!
 
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marshg246 said:
Don't know, but I have three (so I can always use middle of the range) 1/4 drive, 3/8 drive, and 1/2 drive. Always stored on the lowest setting per the manufacturer and always in their case and always in my climate-controlled shop. 1/4 checked against 3/8. 3/8 checked against 1/2. 1/2 checked against two old bar types.

Checked at least yearly and calibration checked about every 5 years. Way more calibrated than my arms that are becoming weaker and weaker!
Click to expand...
Was an A&P so required to have my torque wrenches (Snap-On) calibrated and a mobil service would come around and recalibrate while we waited so for grins I brought in my home use Craftsmans 3/8" drive click type for recalibration, it didn't need any tweaking and was 2# off at lowest setting and came to zero # off midrange and then proceeded to slowly go to 2# off at max setting. Can't complain and can't remember how the others compared but probably similar.
 
Madnorton said:
Greg, The waisted portion of the bolt on the samples we tested were oversize which of course makes them stronger.
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But wasn't the reason Norton made them waisted originally so that there was the required amount of stretch in the waisted section when tightened to the specified torque, thus giving the required clamping force under work cycles? Thicker might be stronger but stretch under torque would be less and upset the whole equation?
 
HopperXL said:
But wasn't the reason Norton made them waisted originally so that there was the required amount of stretch in the waisted section when tightened to the specified torque, thus giving the required clamping force under work cycles? Thicker might be stronger but stretch under torque would be less and upset the whole equation?
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No clue, but my assumption is to make them tight in the rods without making it very hard to impossible to get them in.

On that subject I recently worked on a motor with weird damage to the shells. When I took the rods off, the bolts slide out easily. The rods and even the bottom caps had clearly been reamed. The rods moving around on the bolts, even a thou or two is plenty to cause shell, bolt head, bolt, rod, and/or nut failure. Surprisingly, the journals were OK but I bet there were not a lot more miles until it all let loose.
 
marshg246 said:
No clue, but my assumption is to make them tight in the rods without making it very hard to impossible to get them in.

On that subject I recently worked on a motor with weird damage to the shells. When I took the rods off, the bolts slide out easily. The rods and even the bottom caps had clearly been reamed. The rods moving around on the bolts, even a thou or two is plenty to cause shell, bolt head, bolt, rod, and/or nut failure. Surprisingly, the journals were OK but I bet there were not a lot more miles until it all let loose.
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This is why hand tools, not guns, should be licensed.
 
kommando said:
Where to start,

1. Its from 2016
2. If they are using the original forgings then where does the extra lengthened boss come from.
3. A rolled thread is stronger than a cut thread, cut threads are potential stress raisers. Norvil's threads are cut.

www.earnestmachine.co.uk

What are the differences between cut and rolled threads? - Earnest Machine Products

Are the threads cut or rolled? We are often asked this question in regards to how the threads were manufactured on a particular size bolt or screw that we stock...
www.earnestmachine.co.uk www.earnestmachine.co.uk

The form at the bottom (root) of the thread plays an important role in the “fatigue” resistance of the thread. A radiused (rounded) thread root does improve the thread’s fatigue resistance. Cut threads are often perceived to create a sharp point at the thread root. A sharp point at the root does make a thread more susceptible to fatigue failures as compared to a thread with a round root.
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Quite odd that they should cite cut threads as being preferable to / better than rolled threads in this application…
 
If any of the current ARP vendors can convince them to make conrod hardware like the Triumph boys have had since like forever, then we'll really be on our way!

Original vs Reproduction Con Rod Nuts and Loctite
 

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