RINGS WORN LOPSIDED

[RipperFox]

The old girl got really low compression really fast and I tore her down (thinking reeds). But no dice. Pull the jugs and found the rings worn on just one side about half way down!! Like from 9 o'clock to 12 o'clock on the exhaust side of the piston was like half gone.

 

ANY IDEA W HY THIS WIERDNESS???

 

piston, rings, rehone had like 5 hours total on it too. I am lost as to what is going on...afraid to put new in, might do it again...gotta find out why first.

 

Loose piston maybe? (piston slap)

[blowit]

Exhaust port too large or port chamfer insufficient. This is very common and directly points at these items. Excessive heat can also cause ring bind by closing the ring land gap on the exhaust side. Bottom side of the pistons will indicate this as well as the ground strap on the plugs.

 

 

 

brandon

[THE GRIM RIPPER]

You would have heard piston slaap and you would have noticed damage to the skirts of the piston as well. Did you check your ring end gap after installed in the cyl? (Where the rings would potentailly have connected)

[THE GRIM RIPPER]

True indeed brandon... But you said that you just honed the cylinder?? Or did you bore the cylinder?

[RipperFox]

True indeed brandon... But you said that you just honed the cylinder?? Or did you bore the cylinder?

 

Just honed. Lost the crank and right side piston. Bore was fine so I honed both, new R piston, and reringed both sides(and properly gapped, .010-.012 if I remember right)

Edited August 3, 2008 by RipperFox

[blowit]

Just honed. Lost the crank and right side piston. Bore was fine so I honed both, new R piston, and reringed both sides(and properly gapped, .010-.012 if I remember right)

 

 

Bore or hone has nothing to do with port chamfer. Chamfer is critical for proper ring life. If you are lopsided, there is a reason. Get a close pic of the exhaust port or so some more investigating.

 

 

brandon

[THE GRIM RIPPER]

Bore or hone has nothing to do with port chamfer. Chamfer is critical for proper ring life. If you are lopsided, there is a reason. Get a close pic of the exhaust port or so some more investigating.

 

 

brandon

 

 

Of coarse it has something to do with it... If he only honed out a perfectcly good set of jugs that had a good port chamfer job done previously (that didnt wear rings improperly) then there would be no reason to suspect the port chamfer right? Now, in light of the new info that you had a crank and piston failure and didnt go with a fresh bore??????? Id imagine your prob lies there somewhere

[blowit]

I don't think you followed me. There is no relation between bore/hone and chamfer meaning just because you hone does not mean your chamfer is good to start with! We have built over 1000 banshee engines and I can't tell you how many have improper port chamfer. Not true that port port chamfer will also cause piston problems. Of course we will need more data on this engine to even know what the problem is.

 

 

Bottom of exhaust port will cause rapid ring wear without hardly affecting piston wear.

 

 

Brandon

[RipperFox]

Of coarse it has something to do with it... If he only honed out a perfectcly good set of jugs that had a good port chamfer job done previously (that didnt wear rings improperly) then there would be no reason to suspect the port chamfer right? Now, in light of the new info that you had a crank and piston failure and didnt go with a fresh bore??????? Id imagine your prob lies there somewhere

 

Lost the right side bottom crank bearing and some damage to piston...LEFT side had ZERO damage from melt down...Honed Both, new rings...Left side wore Lop sided.

 

Looked at the bore (right side) very closely and saw (and mic'd) no damage...so I just honed (bead hone)

 

Had no problems with jugs/pistons/rings prior to this crank meltdown.

Edited August 3, 2008 by RipperFox

[bellracing2]

The old girl got really low compression really fast and I tore her down (thinking reeds). But no dice. Pull the jugs and found the rings worn on just one side about half way down!! Like from 9 o'clock to 12 o'clock on the exhaust side of the piston was like half gone.

 

ANY IDEA W HY THIS WIERDNESS???

 

piston, rings, rehone had like 5 hours total on it too. I am lost as to what is going on...afraid to put new in, might do it again...gotta find out why first.

 

Loose piston maybe? (piston slap)

OK , check this out .......... I just did an lt 8o fresh top end and the piston I got from Wiseco was marked .5mm oversize , the box said .5mm , but in reality the piston was std bore ! the rings were correct , wiseco put a std bore piston in the wrong bin and etched it as a .5 over and put it in a .5 over box . what this did was allow the rings to walk around the piston with no locating dowels for the end gap cuz the rings were too big for the piston diameter the gap would not get small enough to contact the dowel on the piston ! I would check the piston closely and measure it to the bore to see if your @ .004-.006 clearence . how far out of round is the bore arount the exhaust port ?