Piston ring orientation - which way is up?

Paul LeClair

Paul LeClair

Administrator
Staff member
Location
Calgary, Alberta, Canada
Hi all

having a blank moment....

on the top two piston rings, does the beveled edge face upwards, or downwards?

it is for my 650 Kawasaki rebuild, I am using 1.00 mm oversize pistons and rings, the new old stock Kawasaki rings finally arrived in the mail today, and the rings have no markings on them and no instructions, usually Kawasaki rings have an "R" marked on them to indicate the top side..... nothing in the Kawa manual to tell me one way or the other in teh absence of the "R" marking.

but, the bevelled edge up or down must be fairly standard, I just can't remember to day.

Thanks in advance

Paul LeClair
 
Isn't there a dot or numbers etched on the ring? If so I'm pretty sure the dot/writing goes up. Googling it found that the bevel sometimes go different ways according to the ring number but the dot spoke the truth.
 
Paul,

Beveled inside edge always faces the top.  Is meant to aid ring sealing on compression, gases(are supposed to) get behind the ring and force it to the cylinder wall.

But, as drikko stated, if there is anything scribed on the ring, this should face the top.... not sure how a lower beveled edge should work, though.

piet
 
thanks, guys.

I got out a much brighter spotlight and a bigger magnifying glass, and found "N 1.00 mm" scribed in the tiniest of typeface, so I will install with that facing upward. Not sure what the "N' means, but the 1.00 surely refers to the 1mm oversize.

Paul LeClair
 
Dellortoman said:
The rings should be installed with the "N" facing north
Click to expand...

North in which hemisphere? Surely they need to point to the nearest pole so Coriolis' Force could force the rings to seal better against the cylinder wall, so they should point north in the northern hemisphere and south in the southern hemisphere. Then you still have to adjust them if you cross the equator.

Ken
 
mcnicol said:
Dellortoman said:
The rings should be installed with the "N" facing north
Click to expand...

North in which hemisphere? Surely they need to point to the nearest pole so Coriolis' Force could force the rings to seal better against the cylinder wall, so they should point north in the northern hemisphere and south in the southern hemisphere. Then you still have to adjust them if you cross the equator.

Ken
Click to expand...

But don't forget to allow for magnetic variational..ie study your isogonals..Coriolis force is not a real force at all..it is only experienced due to the turn of the earth bending the road to the right in the Northern Hemisphere and to the left in the Southern hemisphere. It accounts for my impromptu visits to the pub and houses of ill repute !! ;)
 
Joe, Drikko, I think you're getting mixed up with the guy who invented the Mini - first name Alec or Alex, I think.
 
jotajoe said:
Coriolis force is not a real force at all..it is only experienced due to the turn of the earth bending the road to the right in the Northern Hemisphere and to the left in the Southern hemisphere.
Click to expand...

Joe

That's right, that's why when a hurricane demolishes thousands of houses and businesses in the Caribbean it's not really important because it's not a cyclone. Unless it's a hurricane that crosses the equator (happens occasionally). So even though Coriolis' Force isn't a real force, if it tries to straighten out your piston rings they'll still break.
Maybe that's why old European Laverdas often have their compression rings in 1-2cm fragments, got ridden too close to the equator and all the rings tried to straighten. Australian ones don't seem to have the same problem because you can't ride close enough to the equator. Good thing there's none in Singapore! :D

Ken
 
From what I hear Cyclones in the southern hemisphere spin one way and Hurricanes in the northern hemisphere spin in the opposite direction,so what does happen when they cross the equator,is this spin a consequence of prevailing wind directions locally or something else,or am I typing crap about this spin.The resent cyclone in Queensland was reported as copping it harder on its southern flank as that was where the spin was comming from its leading edge.
 
Quite right Vince. Low pressure weather systems rotate clockwise in the southern hemisphere and anti-clockwise in the northern hemisphere because of the coriolis effect (to do with the earth's rotation). High pressure systems go the opposite way to low pressure systems.

Once a big mass of air is rotating, the coriolis effect is too weak to change its direction. So if a cyclone crosses the equator, it'll keep rotating the way it was before until it fizzles out.

Because of it's circular clockwise rotation, the air in the southern side of cyclone Yasi was moving west while the northern side was moving east. But the whole system was also moving west by about 30km/h, so the sideways speed is added to the rotational speed on the south side and subtracted from the rotational speed on the north side. That means the wind across the ground was some 60kph higher in the cyclone's southern flank than its northern flank.

Cheers,
Cam
 
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