crank sealing rings

[Mark Ambrose]

I have a 2.5 200 mercury,that has broken sealing rings.The motor only has 40hrs since rebuild.I run three gallons of methanol with benol. The sealing rings was not binding and checked for grooves for burrs???????

[HStream1]

JMO they must have been broken at assembly.

[WATERWINGS]

Is the motor an all original motor, or is the crank, and block and front 1/2 from different motors? (mismatched parts)

The crank sealing rings will wear grooves in the ring lands and if mismatched parts are put in a motor, the worn grooves and the crank grooves may not align perfectly as it did with the original parts.....causing a stress/heat on the crank sealing rings.

I had a crank that this misalignment caused a little chunk to come out of the crank, (the edge of the crank groove) and this little chunk went thru the motor.

[Mark Ambrose]

It did not hurt the block or crank.I was told just put it back together and run it.All original motor.

[Jay Smith]

Mark ,
I lap ALL my sealing rings on a honing stone ( you can buy a 12"x12" sheet of glass at the hardware store ) , I use 400 Grit wet and dry sand paper and "figure 8" the rings until they all are flat then I radius the end gap edges and assemble..


Hope that helps,good luck !
Jay

[HStream1]

It did not hurt the block or crank.I was told just put it back together and run it.All original motor.

:confused::confused: I don't know about that. I would replace the sealing rings and lap them like Jay suggested. They will break if the case halfs and rings are not assembled correctly.

[Mark Ambrose]

Thanks Jay Smith, good advice and my next motor will be yours.

[Capt.Insane-o]

I've seen several untouched factory assembled motors with broken sealing rings. Check the crank runout before you put it back together.