Thread: Try not to laugh too hard - am doing mechanics course ...

Originally Posted by Panda

Sorry Deano, I'll have to go back & read it through ... it was the beer I tell you ...

WHAT, YOU'VE RUN OUT !!!!!!!!!????????


Nah, just me being clever. There is actually an external combustion engine. This is where heat is applied externally to the 'cylinder'. The concept has been around for several hundred years.
During WW2 external combustion engines were used as lifeboat engines, also Philips made small generators using an external combustion engine back in the 1960's I think. There was talk of them being used in submarines as there is no 'bang' as in....... suck, push, bang, blow, as they are very quiet and the submarine is less likely to get a torpedo up its clacker. I'm just full of useles info today, or as SWMBO would say ......'just full of it'.

As far as run down torque is concerned I've got no idea. But in your original post about it you mentioned a pin popping or something that made me think of a torque wrench reaching tension. Am I close ???

Deano

To answer my own question
The purpose of an internal combustion engine, is to convert chemical energy into mechanical energy by burning the chemical in a confined space under pressure.
Which intern creates a reciprocal motion (piston going up and down) which intern is converted into rotary motion in the crank shaft via the con rods.
To see how an external engine works google hot air engine
Hodgo

No, certainly haven't run out ... have to concentrate on my mechanicing too much this evening though ... so may have a couple later.

Regarding the "run down torque" ... no, I don't think so. But hence my question, as I don't really understand it. From what I can gather, damaged threads, for example, or foreign material (from the bolts not being properly cleaned), can cause a certain amount of resistance, before "drawing" the parts together. This is apparently "run down torque". Apparently, it's not always noticeable (which is of concern to me, not being experienced enough to know the difference). However, if you do come across "run down torque" you have to add it to the recommended torque. Yes, that's right, I'm getting more & more confused. lol. You're supposed to determine "run down torque" during the last couple of turns ... and how the hell you're supposed to know how to add it to the recommended torque is beyond me ....

Originally Posted by DeanoH

WHAT, YOU'VE RUN OUT !!!!!!!!!????????


Nah, just me being clever. There is actually an external combustion engine. This is where heat is applied externally to the 'cylinder'. The concept has been around for several hundred years.
During WW2 external combustion engines were used as lifeboat engines, also Philips made small generators using an external combustion engine back in the 1960's I think. There was talk of them being used in submarines as there is no 'bang' as in....... suck, push, bang, blow, as they are very quiet and the submarine is less likely to get a torpedo up its clacker. I'm just full of useles info today, or as SWMBO would say ......'just full of it'.

As far as run down torque is concerned I've got no idea. But in your original post about it you mentioned a pin popping or something that made me think of a torque wrench reaching tension. Am I close ???

Deano

Originally Posted by hodgo

To answer my own question
The purpose of an internal combustion engine, is to convert chemical energy into mechanical energy by burning the chemical in a confined space under pressure.
Which intern creates a reciprocal motion (piston going up and down) which intern is converted into rotary motion in the crank shaft via the con rods...........................

you're not related to dave are you ?

Deano

ummmm, unless this is one of your trick questions .... the combusion chamber?

Originally Posted by Blknight.aus

easy name another area where a little spark causes a heap of sucking squeezing banging and blowing to occur.

....................................If the threads are damaged or covered with dirt, you can feel some resistance before the fastener actually pulls the parts together. This is called "run-down" torque. If you can "feel" that 5 Nm of run-down torque is needed to make the nut turn on the bolt, then add this 5 Nm to the recommended torque. Sometimes you can hear a clicking sound and feel the nut "stick" before it gets to full torque. Then, as you apply more torque, the nut does NOT move until you reach a higher value of torque. The cure is simple. Just back-off half a turn, and once it has broken free, tighten it again with a steady and smooth action....................
© Karl S. Kruszelnicki


Pinched this off the ABC website.

Talk about a long winded way to explain a simple principle.

What they are saying is that when you have a dirty or damaged nut/bolt that you are tightening, some of the force you are using to tighten it with is being used up to overcome the friction caused by the dirty/damaged nut/bolt. When you are tightening a nut/bolt to a specified torque you need to apply extra torque to compensate for this 'wasted torque' in overcoming friction. In the example given above they've determined that friction to be 5 Nm. I guess you'd determine this by feel when you're experienced but until then try this. If the nut/bolt isn't "pulled up" and you can feel resistance as you tighten it you'll be able to read the amount of torque required to overcome this resistance on your torque wrench. Add this to the required torque and bobs your uncle, the nut/bolt is now done up to the correct tension.

Hope that makes some sense.

Deano

Thanks Steve ... I still haven't looked up the torque settings yet. But you have reminded me ...

Originally Posted by jackz

Here's a thread that may spark your interest, Panda. As well as induce some lively banter next time Tony has goanna in your shed.
Nissans might have strong axles, but pity about the wheel studs...

Originally Posted by Panda

ummmm, unless this is one of your trick questions .... the combusion chamber?

Aahhhh............................"the innocence of youth".


Deano