Oil Drain plug question

[fotoguzzi]

Maybe I asked before but I forgot the answer,
Do drain plugs use a lock washer?  Why not?

And then why don't they vibrate loose and fall out?

[Kev m]

Most fasteners that don't have a locker washer don't vibrate loose.

Many drain plugs use crush washers, which help to seal.

But vibration generally isn't an issue on those fasteners.

[Pizza Guzzi]

I once ( unknown to me at the time ) rode an hour home from having my 1200 Sport serviced with the engine drain plug finger tight. Frightened me when I thought about what might have happened but there was barely a trace of oil that escaped - point being I have never heard of a drain plug vibrating loose in service. Even though the plug is subject to vibration it's not carrying any external load - as an old timer told me 50 years ago when as an energetic greenhorn I attempted to strip a sump plug thread - just nip it up, it's not going anywhere.

Glenn

[pehayes]

I've always had the same question.  But with the lock nuts on valve adjusters.  Now there is a case for constant vibration and impact forces.  Lock washers??  Nah!

Patrick Hayes
Fremont CA

[pete mcgee]

I have seen an oil drain plug come out with the bloke was riding.
Dont know if had been done up correctly or one of Petes shaved apes had tightened it up till it went loose and then backed it off a 1/4 turn and called it good. But come out it did.
About that time I started using loctite 569 hydraulic sealant on all my vechicles sump plugs. Low strength locking with total thread sealing, no problems in the last 33 years.
Lock washers on other parts depend on the material thats being held and the grade of bolts being used.
Higher quality fasteners like valve adjusters are fairly good quality with a good bearing area for their size and generall dont need a washer.
Alloy or mild steel, a washer is generally used to give the bolt head or nut something of similar hardness to bear on as opposed to a hard fastener bearing on a soft material.

[sib]

I once ( unknown to me at the time ) rode an hour home from having my 1200 Sport serviced with the engine drain plug finger tight. Frightened me when I thought about what might have happened but there was barely a trace of oil that escaped - point being I have never heard of a drain plug vibrating loose in service. Even though the plug is subject to vibration it's not carrying any external load - as an old timer told me 50 years ago when as an energetic greenhorn I attempted to strip a sump plug thread - just nip it up, it's not going anywhere.

Glenn

It's interesting that although there are few if any reports of drain plugs vibrating loose, there a plenty of reports of dipstick/oil filler plugs vibrating loose and falling out of Moto Guzzi engines.  It happened to me on my "13 V7 Stone.

[acogoff]

     Maybe the vibrations are dampened a bit by the oil it is holding in. Just guessing.

[Cam3512]

Yet on the V7's, the dipstick is prone to vibrating UP and out?  What gives Beave....?

[Kev m]

With the dipstick on smallblocks there's an o-ring that provides the seal when tightened that is prone to dislodging or to go missing and THAT'S generally when vibration might walk it up the threads.

[Huzo]

I drilled a hole through the head of the sump and gearbox drain plugs on the Norge.
There was a time when I lock wired them, but I don’t now.

[Kev m]

I drilled a hole through the head of the sump and gearbox drain plugs on the Norge.
There was a time when I lock wired them, but I don’t now.

DAAAAAYYYYUUMMMM

YOU make ME look NORMAL and that shyte ain't easy!!!

 

[Huzo]

DAAAAAYYYYUUMMMM

YOU make ME look NORMAL and that shyte ain't easy!!!

 

But, but,but..
It says under your name that you are “not your normal Hombre...”
You sounded normal on the ‘phone.

[pete mcgee]

Lockwiring, like anything else gets easy with practice.
32 years of airframe/engine maintenance, only do it now when I absolutely have to, or if someone I know who races needs it done on their bike.

[sign216]

With the dipstick on smallblocks there's an o-ring that provides the seal when tightened that is prone to dislodging or to go missing and THAT'S generally when vibration might walk it up the threads.

On the old smallblocks (Nevada, Breva, V7) the dipsticks tended to auto-rotate all the way out.  There's even a story about a woman out west who lost her Nevada's dipstick, lost too much oil, and toasted the engine.  Might be a myth.

My disptick fell all the way out early on, but I noticed it (after my boot got covered in oil).  Now I wire my V7 dipstick in place, and another fellow pinned it in place.  As for cars, I have a friend and the engine oil sump drain bolt did fall out.  It was some time after he got it changed at one of those quick lube places.  Destroyed the engine.  He thinks they hand screwed it in, but never wrenched it tight.  Could never prove it though.  Joe

P.S. The photos didn't load in order, but you can understand.

[Cam3512]

I went with one of these on my V7.  Stays put.  Most of the oil inside eventually evaporated.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F121220339329

[Kev m]

I've used a 3D printed dipstick tightening tool (from OZ) since day one Dec/2012 and it's never loosened. But I play close attention to the o-ring and snug it well. So well I tap the end of the tool lightly with a rubber mallet to loosen it.

But, but,but..
It says under your name that you are “not your normal Hombre...”
You sounded normal on the ‘phone.

You see, but you've got a twisted sense of normal.

[Tom]

I like drilling the oil cap/dip stick. (plastic)  I put some silicone tape or is that a no no?

[John A]

To answer the original post, friction is what keeps it in.

[fotoguzzi]

To answer the original post, friction is what keeps it in.

F>L

[John A]

F>L

Yes

[Kev m]

To answer the original post, friction is what keeps it in.

And wouldn't that be true for all fasteners that don't use threadlock?

[Kiwi_Roy]

I like drilling the oil cap/dip stick. (plastic)  I put some silicone tape or is that a no no?

Teflon tape is used on tapered threads, like pipe threads not parallel as the dip stick has.

I like this solution by sign216, you wouldn't have to tighten it so tight you need a wrench.
https://i.ibb.co/THDH02K/Tom-Farley-s-mod2.jpg

[wirespokes]

Yeah, friction keeps them from backing out. Good answer.

As for the tappet adjusters, that's more like a jam nut - locking two nuts together on a bolt. The friction of the two against the threads, plus against each other prevent their moving. And you don't need a washer against another nut.

My guzzis are all tontis with the huge dip stick nuts. I've never had a dip stick that required a wrench to remove. Guess some torque is needed to make them hang around.

[Sasquatch Jim]

 Yes, fiction is what holds them in. That is why shaved apes at dealers tighten then enough to gall threads.  That way if they strip coming out they will tell you it is your fault, that they did not leak after they put them in.  Dealer solution to problem.

[Kiwi Dave]

I've used a 3D printed dipstick tightening tool (from OZ) since day one Dec/2012 and it's never loosened. But I play close attention to the o-ring and snug it well. So well I tap the end of the tool lightly with a rubber mallet to loosen it.

I purchased one of those too, it works well.  Basically the dips tick is only able to be hand tightened which is insufficient in my opinion.

[Huzo]

Yes, fiction is what holds them in.

So do I jam a good paperback between the threads ?
Mills & Boon...? John Grisham....?

[John A]

So do I jam a good paperback between the threads ?
Mills & Boon...? John Grisham....?

 

[Italianmotofest]

And I always thought that was the reason we’re supposed to replace the crush washer on a regular basis.  But hey, what do I know?

[wirespokes]

The washer doesn't keep the bolt from falling out so much as sealing. The crush washer gets work-hardened and doesn't seal as well second time around. Use a new one or anneal it.

[Murray]

Something about A,B,C and D tolerances on thread machining, a google machine will explain it better than I can, even in the humble everyday thread that you don't ever really think about 100's of years of development calculated engineering and plain old trial and error have refined the process.