Thru bolt torque

[axl911]

According to the manual, the torque value for the through bolt is 50Nm or 37 ft-lb. Is the thru bolt torque of 37ft-lb a realistic value? The nut seemed to be on MUCH tigher when I break it loose.

thanks,
anthony

[galwaytt]

Originally posted by axl911
The nut seemed to be on MUCH tigher when I break it loose.

thanks,
anthony

How do you know how tight it was............? If it just 'felt' like it was, it doesn't mean anything. Could've been overtightened in an earlier life either by accident or to cure a weep............

[axl911]

I did not measure it, but can. I know it was TIGHT since I had to use a really big breaker bar.

In addition, I had to loosen and retorque one of the through bolt nut I took off. It was WAY easier to loosen.

I don't want to undertorque the through bolts since it can leak and require another top end rebuild to fix.

---anthony

[galwaytt]

Anthony - no need to measure - as a matter of fact, you can't! There's no correlation between how tight it is to open vs how much it takes to tighten it up........if you follow me?!

Or course, if there was a threadlocker on it, it'd distort it even more.

More important to apply book values to new assemblies rather than worry about what has gone before.

[350HP930]

Over time the thread lubricant slips away and a strong friction bond forms between the threads. The torque to break loose an old fastener can be several times greater than what the fastener was originally torqued to.

[axl911]

Well, I measured the breakaway torque of the nut. It's all over the place ranging from 65ft-lb to 40ft-lb. There were some I didn't measure but felt much more than 60 ft-lb. They felt tighter than my lugnut.

---anthony