Ring seating, heat transfer

[modok]

lapping is using an abrasive.
The term "burnishing" would be more correct.

[jed]

Burnishing could apply but my thinking was the oil was the fluid used and the wearing away if the honing peaks
furnished the abrasive ending up lapping in the rings and wearing down the peaks of the freshly honed cylinder.

[jed]

And I am almost to the point of agreeing with you Modok that the rings are close to running in the boundary layer
Mode of lubrication

[modok]

Studying boundary lubrication is really weird, so the definition of what actually is and isn't, is kinda cloudy.
Can't SEE what's happening, we just get strange little clues.

If you do actually have two BARE metal surfaces in true contact with each other, they will weld together. But, creating a condition where you have both bare metal AND being in perfect contact, is actually.... almost impossible to do.

Unless in a vacuum, "bare metal surface" only exists very temporarily, quickly reacting with whatever it is touching.

Gauge blocks will wring together in a vacuum chamber. But the most likely explanation is because wringing them together makes small interlocking scratches..... at least that's my theory.

Not an easy riddle!

[Truckedup]

Were the barrels bored/honed on torque plates?
Was the bore/hone done slowly enough to prevent overheating of the unfinned(exposed) section of the barrel liners?
Did he allow a decent number of minutes for a full warm-up before hammering the throttle?

He bought the bike knowing it needed valve work...Removed the head ,work at been done but the engine not run...Fresh bore and hone that looked good but seriously doubt any used a torque plate.. Very few builders of old Brit street bikes use torque plates from what I see out there..I use one on Triumphs but there's so much stuff wiggling and squirming around inside the engine it may be like a finger in a dike..That's what they like cast iron rings with a rough hone that will wear in ...I use modern ring materials and have no problems with cylinder seal..

[modok]

What was the rod bearing clearance? and what oil? what ambient temp?

i don't even know what oils the cylinders, but whatever it is, maybe it can be improved?

[Truckedup]

What was the rod bearing clearance? and what oil? what ambient temp?

i don't even know what oils the cylinders, but whatever it is, maybe it can be improved?

I have no idea about clearances Not my bike , but if it, I were know....The cylinder is oiled by the crankshaft oil spray, 20/50 oil is universally used in these things. These kind of problems don't happen even when racing if the engine is reasonably close to specification..

[modok]

don't want to send you in the wrong direction, but maybe look into it.....

20-50 oil and TIGHT bearings, on a chill day, is pretty much THE classic story of disaster.
I've done it, everybody has done it, and they aren't going to quit doing it any time soon.

Bearing clearance/oil viscosity/temp relationship is just a lot more touchy than most people realize.

[modok]

At one time I was either told or read that very fine finish gauge blocks stayed together or wrung together because of very light metallurgical adhesion. Similar to magnetism. Now I'm wondering about ceramic?

I don't know, what kind of materials you can get to wring together and which you can't, but I have a feeling it would be a heck of a learning experience.

[hoodeng]

Seizure along the gudgeon boss line usually is a sign of rapid temp rise in the piston crown,metal smearing on the thrust face of a piston is oil film breakdown ,metal smearing front and rear of a piston is a plug too big for a hole.Classic full seizures happen in the first full heat soak cycle of an engine or close there to,seizures after a couple of thousand miles but still early in an engines life usually has some other influence than the bores fit.Poor lubrication or excessive heat.

Gauge blocks have to be prepped from storage for wringing,,they don't need to be in a vacuum ,under the lid of my set is a piece of chamois that the blocks mating surfaces are cleaned on before assembly ,they are then slid across each other at 90°till half way then turned 90°that's it,to dissemble rotate block 90° and slide apart.As apprentices we were told any other method could irreversibly damage the block. Primarily we were taught to use the blocks to set up a sine table,all i use them for now is checking mikes.

Cheers.

[nm9stheham]

According to the chart on page 12 the oil rings transfer more heat than any other ring.
I don't quite understand how because the oil ring rails, when considering surface area, have the least contact
area of the other 2 rings.
And after reading all the posts how can top 2 rings transfer/dissipate heat through so little a surface area?

Are your referring to the M.I.T. presentation? If so, amount of heat transfer from each ring is proportional to the size of its segment within the column, so the top ring transfers the most.

The heat transfer is proportional to the contact area, the contact pressure on that area, and the temperature differential. The pistons is obviously hottest at the crown and ring pack area, so the temp differential will force a lot of heat across that junction. And the ring pressure on the cylinder is much larger compared to any pressure against the cylinder wall by the skirt. So there are 2 of the 3 factors pointing to the rings as the path for the most heat.

[modok]

I know they don't have to me in a vacuum.
It just shows that how they stick isn't related to air, although if not for the experiment I would have assumed it was.

[Dan Timberlake]

According to the chart on page 12 the oil rings transfer more heat than any other ring.
I don't quite understand how because the oil ring rails, when considering surface area, have the least contact
area of the other 2 rings.
........................

On the "stacked" bar graph The % cooling is the vertical height of the ring type's band, not how high up the bar it is.

[randy331]

I've seen a direct correlation between ring tension and oil temp on engines I've had on the dyno.

The ones with real low tension oil rings,. napier second,..etc,.. thin stuff,.. takes a pull or 2 to get oil temp up some.

On more conventional stuff 1/16 1/16 3/16 standard tension, oil temp comes right up.

Randy

[jed]

Randy were the running oil temperatures of the convention ring pack and the light ring pack the same??