dimwhit question of the day

[ironman]

hi all .... doing an oil change on mk 2 1200 adv. replacing the sump plug the Haynes manual says the torque setting is
initial setting .... 23 nm
final setting ..... 32 nm
what does initial and final settings mean ?

cheers

 

[Magwych]

First, set your torque wrench to 23Nm, and tighten the plug; then set your torque wrench to 32Nm and tighten again.

Why? No idea, I just tighten to 32Nm, per the RepRom CD.

Now, be prepared for some abuse

 

[ironman]

thanks .... there must be a reason ... but hay ho

and its ok I have very thick skin i'm married to a scouser

 

[Pukmeister]

First setting is to seat the crush washer. Second setting is to crush it enough to effect a seal.

You did fit a new sump washer didn't you ??

 

[(RIP) Mark H]

Here's my theory for what its worth,

Tighting a steel drain plug into an ally sump has its dangers of stripping the thread, but it needs to be tight, close in fact to were it may strip the thread,

So the recommend to tighten to 23nm first is to prevent overzealous tightening going past the warning "click" of 32nm, by doing it in 2 stages it lessons this risk somewhat

I cant think of any other reason for this recommend.

Course if you've done a few before you can always just whack it up with an ordinary ring / socket spanner and judge it!




.

 

[zoot]

Puk get the points on this one

 

[Leekyboy]

Torque relaxation on a 'new joint' with a copper washer. The initial torque relaxes with the initial crush and the clamp load is low, second application achieves the required clamp load to achieve a good seal.

 

[ironman]

cheers chaps .. and yes Puk I did fit a new washer

 

[Boxerboy55]

We'll be gentle
No silly questions around here.

My last sump plug washer was plain alloy so it gets tightened in 1 shot, sans torque wrench. It's not a real crush washer - as found on many spark plugs. Now that's when you get to feel "crush".

As above, I can only assume the 2 step guide is try to stop a heavy handed Harry from stripping the thread right off the bat.

But, here's the lesson learned, after successfully tightening your sump plug to torque xyz, go grab a ring spanner and feel how tight the plug is. Probably not even "a small grunt".

Then you'll know how tight to make it next time - without using a torque wrench. They are dangerous things in the wrong hands. Especially bolting into ally.

In fact, you could of had a wee play with the sump plug with the old washer before you put the new oil in. Go try to get a feel for what you're tightening.

 

[Bendy toy]

Try doing a head gasket with stretch bolts then a torque wrench does come in handy.

e.g. 20ftlbs all around then slacken. Followed by 30ftlbs and finally 2 stages of 90 degrees in the correct pattern. Clearly without the torque wrench there would be all sorts of problems.

But generally a torque wrench gives a false sense of security. In 35 years of home spannering I have had one or two stripped threads due to my own clumsiness. The other few were already damaged in some way so were helicoiled before they stripped out.

My torque wrenches are there for when needed but they hardly ever come out of the toolbox.

PS With sump plugs it's all too easy to get confused about which way to turn the spanner so the plug gets over tightened (damaging threads) when we mean to be loosening it.

 

[ironman]

as it happens, I was expecting a copper washer but the old and new one was alloy. and didn't think much of it, so I could have nipped it up to 32nm straight off . and would have saved a lot of head scratching, typical of me though .
on a happier note we have just come back from a four day holiday blatting around Scotland.... 1st time .... but not the last, fab roads and scenery.