Torque Just to hold Plug in Place
Torque Just to hold Plug in Place
(OP)
Hi all,
Hopefully a very simple question...
I have a 'plug' made from steel, M22 X 2 thread, which is going into a cast aluminium threaded hole. It is acting purely as a plug, i.e. not clamping anything down.
All I want to know is how to work out a sensible torque to do the plug up to so that it is not going to work itself loose.
Thanks in advance
Hopefully a very simple question...
I have a 'plug' made from steel, M22 X 2 thread, which is going into a cast aluminium threaded hole. It is acting purely as a plug, i.e. not clamping anything down.
All I want to know is how to work out a sensible torque to do the plug up to so that it is not going to work itself loose.
Thanks in advance
Regards,
Jon Reynolds





RE: Torque Just to hold Plug in Place
If there's a land, and low non-cyclic pressure, I would say a snug-tight condition. If higher pressure or cyclic, I would torque to a safety factor of at least 1.25 on the pressure equivalent.
That's just "gut feel" from a structural guy! I'll yield to the gearheads for a real answer!
RE: Torque Just to hold Plug in Place
Thanks for the answer.
The plug bolts down onto its underhead area. It actually clamps a collar between itself and the workpeice, but this is purely to adjust its distance into the piece.
There will be a constant force of ~170N from the inside (a spring).
How would you quantify 'snug-tight condition'?
It seems like a silly question, as most engine builders will have a feel for whats good enough not to come out...but I just think there must be some maths behind this to support it. Plus the builder really would prefer to be given a number (so he isn't held accountable probably).
Regards,
Jon Reynolds
RE: Torque Just to hold Plug in Place
I would get in touch with the manufacturer of the oil pan for their recommendations
RE: Torque Just to hold Plug in Place
So calculate your preload and torque for those two cases and select appropriately.
Consider using Loctite to prevent it from loosening.
RE: Torque Just to hold Plug in Place
Do you have any gaskets or o-rings in the joint? Soft copper washer or other? Without one of these, in general, mating standard metric threads will not be leak proof. You will need some fastener magic, such as thread sealant (Loctite being one brand), thread masking (e.g. PTFE tape), or thread forming fastener (e.g. Taptite).
RE: Torque Just to hold Plug in Place
All drain plugs should have a washer, nylon, fiber,aluminum, or copper, They do make drain plugs with a built in O-ring.
Torque is a little misleading if you changed from the O,E.M. one as there are some have longer threads, which have tendency to bind during insertion.
If you strip the threads in the pan and have to go over size the torque values for said plug is on the package./
The standard technique practiced by the roll in, roll out oil changing bunch is to use a standard box wrench and pull it tight using one finger.
RE: Torque Just to hold Plug in Place
It's not an oil pan drain plug. I'm guessing timing chain tensioner.
RE: Torque Just to hold Plug in Place
to be a bit more specific perhaps might help.
This is a plug holding a spring into a hole, which in turn is acting against a plunger for a pressure relief system.
There is no seal as 100% leak proof is not a requirement. This part just holds the spring in the hole against the underside of the plunger.
There is a steel collar between the plug and casting, which allows us to vary the spring pre-load.
I just want to make sure we torque it enough not to work loose but not too tight to risk stripping the alum casting.
Thanks again.
Regards,
Jon Reynolds
RE: Torque Just to hold Plug in Place
Tobalcane
"If you avoid failure, you also avoid success."
"Luck is where preparation meets opportunity"
RE: Torque Just to hold Plug in Place
Mike Halloran
Pembroke Pines, FL, USA
RE: Torque Just to hold Plug in Place
Regards,
Jon Reynolds
RE: Torque Just to hold Plug in Place
RE: Torque Just to hold Plug in Place
None. Your reply made sense to me thank you. I was just following up with more detail as other were starting to guess what was going on.
Thank you.
Regards,
Jon Reynolds
RE: Torque Just to hold Plug in Place
TTFN
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RE: Torque Just to hold Plug in Place
Depending on the engine the supply house should have a list. The last one I saw was from Crane-Cams
RE: Torque Just to hold Plug in Place
At least use Loctite.
I'd try to turn the spacer/collar into a French lock.
Mike Halloran
Pembroke Pines, FL, USA
RE: Torque Just to hold Plug in Place
I just wanted to run it past people here in case there were some obvious calcs I could run.
Thanks for all your thoughts and feedback.
MikeHalloran, I am curious as to what a French Lock is. I can't find much on Google about it. Could you possibly enlighten me?
Regards,
Jon Reynolds
RE: Torque Just to hold Plug in Place
After the fastener is seated, one ear is hammered up against a flat of the fastener, and another ear is hammered down over or into some feature of the substrate.
Mike Halloran
Pembroke Pines, FL, USA
RE: Torque Just to hold Plug in Place
The last one of the French Locks I saw called out as such was used on the Chevrolet Caviar exhaust manifold.
http://www.bokers.com/tab_washers.asp
RE: Torque Just to hold Plug in Place
If it's never intended to be undone, some form of staking might be doable.
TTFN
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