Sump Plug

[Greenman14]

I've got a torque wrench now, and I use it. But I've dismantled and rebuilt engines without one and never had a problem. Generally I found using the torque wrench that I was not tightening up as hard as I had done by feel. Torque figures are very dependant on thread lubrication, and the condition and lubrication of the interface between the component and the washer/bolt head. Where it really matters tightness is calculated by measuring the bolt extension.

If the OP is unsure then a few practice runs with similar size bolts would be useful- anneal the old sump washer, as said by Smug, and use it as a tester.

 

[Bendy toy]

Ive never looked closely at the sump plug & drain hole but a Dowty washer might do a better job.

 

[Alan R]

The torque figure on the various oil retaining plugs are calculated for an oiled thread.

Is this as it reads... a beyond doubt, referenceable fact? Or opinion?
If a fact, can you please back it up with a reference source? This is a genuine question, not a dig as I am also one of those people who feel that the torque setting feels too tight with oiled threads.
Alan R

 

[MattW]

Is this as it reads... a beyond doubt, referenceable fact? Or opinion?
If a fact, can you please back it up with a reference source? This is a genuine question, not a dig as I am also one of those people who feel that the torque setting feels too tight with oiled threads.
Alan R

My 'reference' is the factory service manual.
This specifies 'clean dry threads' (and thread lock or anti-seize compounds) where it matters.

The torque setting on all the various drain and filler plugs are specified in order to allow the new annealled aluminium crush washer to deform and seal. They aren't specified with the plastic limit of the parent metal in mind and it would be patently ridiculous to expect an oil drain orifice threads to be oil free. That said, all bets are off if you reuse an old already crushed washer or a different material.

 

[Bendy toy]

Spark plugs also use crush washers but in the end the tightening torque is the same.

 

[Alan R]

My 'reference' is the factory service manual.
This specifies 'clean dry threads' (and thread lock or anti-seize compounds) where it matters.

The torque setting on all the various drain and filler plugs are specified in order to allow the new annealled aluminium crush washer to deform and seal. They aren't specified with the plastic limit of the parent metal in mind and it would be patently ridiculous to expect an oil drain orifice threads to be oil free.

So the reference is for 'clean dry threads'. You infer that those figures also translate to oiled threads, which is more nuanced than your definitive first statement. I tend to agree with you but I have problem with opinions being offered with out qualification as hard fact.
Alan R

 

[MattW]

So the reference is for 'clean dry threads'. You infer that those figures also translate to oiled threads, which is more nuanced than your definitive first statement. I tend to agree with you but I have problem with opinions being offered with out qualification as hard fact.
Alan R

And I have a 'problem' with people not understanding the mechanics of what the intention of the torque settings are all about. Clean or oiled will not be mechanical issue if the torque setting is specified to crush the washer (not to achieve a certain joint compression or protect the parent components). What may happen with a dry, unlubricated sump plug is that friction may mean that the washer may not crush sufficiently and it may leak (and / or the plug fall out).

The reference isn't for clean dry threads, no pre-condition is specified for the drain plugs. I guess the manual authors didn't think people needed telling that the sump will be oily.

Tell you what - you continue to degrease and clean the sump and plug every time you do an oil change. I'll leave them oily. Everyone's happy...

 

[st247]

Only in here could following the manufacturers manual cause the sme end result as not following it! Good effort!

 

[cookie]

last BMW sump washer i used wasn't a crush washer, just a crappy solid aluminium ring.

 

[MattW]

last BMW sump washer i used wasn't a crush washer, just a crappy solid aluminium ring.

Still a crush washer (just not one of the two layer steel spark plug type).

They're annealed aluminium and are designed to squish when torqued down - they end up half the thickness when used.

 

[MWH]

When I was at college we were encouraged to use torque wrenches. Set a Snap on wrench at 8nm for a GSXR clutch, on first bolt thinking this is getting tight but no click then bang as the thread stripped!

Prefer feel on smaller bolts and torque for wheels, heads etc. I know some people don't tighten spark plugs enough because of the feeling of the washer deforming makes them think its going to strip.

Need to change the wheel bearing on my Transit, torqued up to 425nm, think I may let the professionals do that one, my wrench only goes to 150.