Oh dear oh dear someone been a little rattled!
Mr Lumpy seems to be attacking my statement of "
Because when heated as you say it goes soft and grips the plug threads which makes removal harder and can and does strip threads, plugs should never be removed when an engine is hot."
The statement is
incorrect and should have read "it
stays soft and grips the plug". Teach me to read things before hitting the button.
But doesn't I feel warrant his responses the key to the whole subject is in the next sentence.
"
You being an engineer will know steal and aluminium do strange things when put together one being they tend to seize if the isn't something between them e.g. plug threads have a lacquer on them for that very reason." Aluminium has a property which allows it to grip it's self and certain other metals when heated or stressed i.e. over tightened why because it's soft among other things. Apply enough stress/heat/pressure and the stuff almost bonds to other metals e.g. plug threads, when flat surfaces are involved it can act like its been spread into the surface bit like chocolate. Which is why fine threads are chosen (more on threads later) and manufactures lacquer or coat them. As also pointed out steel and aluminium expand at different temperatures they also contact and gain and loose heat at differing rates the steel plug will contract slower then aluminium head, the head will grip the plug more then it would if the engine was cold. If you have a plug in the head that's been over tightened, wet (oxidised), stripped of lacquer/coating or has crap in threads and you undo it while the engine is hot you WILL increase the
risk of stripping the thread.
Mr Lumpy's comparisons of exhaust header nuts/studs and drain plugs to support his argument of not removing plugs on aluminium engines when hot is not apples for apples and it really clutching at straws matey.
Exhaust headers on most bikes are a stud and nut certainly is on the Fazer, the stud is torqued into the head at about 18Nm and the nut torqued to 10Nm
BOTH are steel the extra torque holds the stud in there hardly a comparison. Drain plugs are usually about 10mm long ish going through the aluminium/alloy or in some cases magnesium (both harder then cylinder head aluminium) sump of about 3 - 5mm thick using a course thread said we'd get back to them. Your average plug in most Jap engines are 25mm ish long going into a soft aluminium head using a fine thread. The thread contact surface area on the sump plug compared to the plug is tiny, you also tend to have a bit of oil about to lub things, drain plugs in my experience are buggered due to over tightening or cross threading full stop!
Fazerrider your comparison is also not right mate
you would have used one of two methods depending on what the issue was. Yamaha/Suzuki tend to put locking agent on their disc bolts and not all of them either just to catch you out
One method to break the adhesion is to apply gentle rapid heat to the bolt head
ONLY this softens the locking agent allowing you to undo the bolt. The other method is to heat the local area around the bolt to expand the area releasing the threads assisting release, BOTH methods you only heat
ONE part not like a plug/cylinder head where
BOTH are heated.
The other area I will take issue with is "
If he also knew about copper grease he would know, although thermally resistant to a point, it is a major no no once the evaporables evaporate and it becomes a congealed mass. You can look that up on the internet too." There are two main types of anti seize grease that are in use one for heat and that used to stop oxidation i.e. water ingress. Most stuff sold as copperslip (trade name) or anti seize grease is the latter and when heated to anything like exhaust temperatures just burns off and provides no protection in can and does act like locking agent in these applications. Then there's proper copper grease designed to withstand exhaust temperatures, particles of copper suspended in a carrier the carrier burns off leaving the copper particles behind it doesn't turn into a congealed mass but a layer of copper!
The last bit of your statement
You can look that up on the internet too is the clue to your majority of you're knowledge fella.
I'm certainly not a fountain of all knowledge never will be and I'm always ready to listen to others, I share my experiences with others to help them should they want to use it is up to them.
Personally I feel people like you who hover around internet forums being rude and aggressive focusing on an error because a person has posted something incorrectly, got the wrong end of the stick or as in this case didn't edit things thoroughly. Then posting knee jerk derogatory comments supported by stuff they find off other forums or the internet and backed up by some claim to being an engineer for Ex amount of years etc etc, are quite frankly sad little bullies.
End of the day Mr Lumpy I don't give a toss what you think or what you're opinion is
others I'm sure will draw their own conclusions!
The end