mrbigg

My Feedback: (21)

I'm thinking of putting a new ring in this engine. It's pretty on compression. Should I go with Frank Bowman's ring or just use the OS replacement? What should I use to scuff the cylinder? I don't think they make a cylinder hone that small.

on pipe

Mr Bigg, Either ring will work, Frank does top-notch work. I've used a number of his rings and they were perfect runners. Just "hone" with a piece of 400 wet/dry wrapped around your finger. Use some lube. (penetrant, etc.) Try to use a twisting motion to replicate the crosshatch marks of a hone. This is assuming the sleeve isn't TOO worn. Ross

DarZeelon

Mr Bigg,


I agree with Ross.

Frank makes rings are probably even better and for sure less costly than the OEM.


The purpose of the honing of the sleeve is:

1. To break any glaze that exists, which might otherwise interfere with the break-in of the new ring (too smooth a surface will not wear the ring down to a perfect match).
2. To create miniature scratches that hold oil, to facilitate break-in...

mrbigg

My Feedback: (21)

Thanks guys. One more question. To get the rod off the crank pin, I had to pull the sleeve out first. There just wasn't enough play at the wristpin to allow the big end of the rod to slide off. Now I'm wondering how am I going to get it back on the crank. If I leave the liner out, drop the piston/rod assembly in the hole, hook up the rod to the crank, how am I going to compress the ring so that the sleeve would slide down over top the piston?

DarZeelon

MrBigg,


Removal of the sleeve was an imperative stage, of course.

Try turning the engine to BDC, so the up-most part of the con-rod is accessible... Now grab it with a pair of needle-nose pliers, with tape-wrapped jaws and pull it rearward as far as it will go.

Afterward, turn the engine to TDC and pry the bottom-end off the crank-pin with your fingers, or with a small Allen wrench.

The chamfer at the front of the bottom-end bore should allow the rod to be buckled enough to unhook from the crank-pin.


...After all, if you need to apply some force to unhook the con-rod, then when this engine was assembled a similar force had to be applied to get it hooked up...

mrbigg

My Feedback: (21)

Thanks Dar. I'll just "persuade" it abit.

Flyboy Dave

My Feedback: (21)

....use a coarser paper to prepare the cylinder wall...150 is good.
400 won't scratch the surface enough. [)]

FBD.

proptop

My Feedback: (8)

I don't know if that ring is pinned, but I'm willing to say that it probably is...

The sleeve has a chamfer on the bottom edge...and you need to be sure that the ring end gaps are aligned on either side of the pin in the ring groove.
Use a little oil, and bring the piston to TDC, and work the sleeve down, compressing the ring as you wiggle/jiggle it around the piston.
I like to tilt the sleeve slightly, and start to work it down 180 degrees from the end gap...that way you can squeeze the ring ends together as you work the sleeve down around the ring.
Be careful not to allow the end gap to align with a port opening either...or you can damage the ring.

Flyboy Dave

My Feedback: (21)

....use the 150 paper and make it look like this if want the new ring
to seat properly. [)]

FBD.