FWIW...I just took a brand new Sachs 5.8 cylinder out of the box...Never assembled, never used, BRAND NEW...
Smooth as a baby's butt...Only visible marks are come miniscule completley ROUND marks left on the bore from the final honing operation after plating...NO crosshatch....Y'all do what you believe is right....I'm done...

Originally Posted by rcign

FWIW...I just took a brand new Sachs 5.8 cylinder out of the box...Never assembled, never used, BRAND NEW...
Smooth as a baby's butt...Only visible marks are come miniscule completley ROUND marks left on the bore from the final honing operation after plating...NO crosshatch....Y'all do what you believe is right....I'm done...

Than the rings will NEVER SEAT. Im done also.

OK, this should add fuel to the fire. I have a very low time Zenoah GT-80 here. One cylinder has visible cross hatch honing, the other just honed in a circular pattern. I have no way of knowing how or when the honing was performed but know it is from the factory that way. A Brison 2.4 and an old Quadra 75 here both have visible cross hatch honing. A DA-100 has bores that fit Ralph's "smooth as a baby's butt" description. No hone marks at all. Have seen full scale jugs with and without cross hatch honing. Depends on what they are plated with or if they're plated at all. Maybe I should call that surface treatment rather than plating?

While this may not be related to airplane engines, I use to build race car engines with a very rough cross hatch hone as that was considered necessary in those days. More recently and with better quality rings available, most are honed to a very fine finish. These engines are race ready after just a minimal run in time and the smooth bores are very kind to piston skirts. These are cast iron or steel bores though which changes the rules quite a bit. Does show that opinions on what a necessary hone finish should be does change with time and with the materials used. Smooth does seem to be the trend.

Originally Posted by Truckracer

OK, this should add fuel to the fire. I have a very low time Zenoah GT-80 here. One cylinder has visible cross hatch honing, the other just honed in a circular pattern. I have no way of knowing how or when the honing was performed but know it is from the factory that way. A Brison 2.4 and an old Quadra 75 here both have visible cross hatch honing. A DA-100 has bores that fit Ralph's "smooth as a baby's butt" description. No hone marks at all. Have seen full scale jugs with and without cross hatch honing. Depends on what they are plated with or if they're plated at all. Maybe I should call that surface treatment rather than plating?

While this may not be related to airplane engines, I use to build race car engines with a very rough cross hatch hone as that was considered necessary in those days. More recently and with better quality rings available, most are honed to a very fine finish. These engines are race ready after just a minimal run in time and the smooth bores are very kind to piston skirts. These are cast iron or steel bores though which changes the rules quite a bit. Does show that opinions on what a necessary hone finish should be does change with time and with the materials used. Smooth does seem to be the trend.

If smooth is the trend, why did your gt-80 have crosshatch?

Any of the cylinders that had visible cross hatch were also very smooth. I don't know if the cross hatch was pre or post plating, etc. I do not claim to be an expert on gas 2 stroke cylinder wall plating, treatment or hone technique ... just a casual observer here.

I do have to disagree with Ralph regarding glo engine cylinders. Many glo engines have a very visible cross hatch hone when new. Some are quite course in my opinion.

Old design??

Just for informational purposes, some of our engines also use steel for the rings instead of iron. One major manufacturer uses both iron and steel rings. You never know what will be in the engines when you get theirs.

Aside from opinions, wich will vary from one application to another, why dont the manufactures supply us with the proper and recomended methods of repair. I have a very large collection of tech manuals ranging from the quad to transmissions. Every one of them from the manufacturer stating theory and operation, torque specs, diagnostic procedures, repair methods. Some even containing modification methods. It sure would be nice to see a manufacturer step up to the plate and publish info. These are mechanical components we are talking about here and opinions are not the final answer that should be relied on. I appreciate everybody's input, but I now see the problem here. Its not that Jack's answer is right or wrong, or that T.O.M is right or wrong, etc, but that the manufacturer did not inform us of THEIR methods. I sent a PM to Pe, hopefully he will supply me with the EXACT procedure. At this point I can easily remove the cylinder and hone if need be. Hell, I hope he can tell me for certain if the cylinder is coated. It sure looks like it.

Originally Posted by jack strickland

If smooth is the trend, why did your gt-80 have crosshatch?

It's under the coating and shows through, or at least on a couple of my engines as per the manufacturer.

Diamond is the hardest substance on the planet...It takes a diamond hone to make the surface of a hard chrome or nikasil surfaced cylinder smooth enough to be used with cast iron piston rings..
Maybe some of you experts can tell me how cast iron rings could be expected to smooth a rough cross hatched surface....If the surface was not honed smooth from the factory...
Anyone ????

Here is a link to a company that does the plating. 180 bucks and they will strip, apply and hone, for 50cc on up. Not that bad. The cylinder on my engine is well over that price. I wont do it though. Just an FYI.
http://www.lukesracing.com/luksr/np.html

Originally Posted by rcign

Diamond is the hardest substance on the planet...It takes a diamond hone to make the surface of a hard chrome or nikasil surfaced cylinder smooth enough to be used with cast iron piston rings..
Maybe some of you experts can tell me how cast iron rings could be expected to smooth a rough cross hatched surface....If the surface was not honed smooth from the factory...
Anyone ????

Consider this, The hone job is very shallow, one cannot feel it. Perhaps the seating is done at the moleculer level and therefore does not affect the pistons, and only helps the rings to seat. I know this from experience, checking compression without honing is less than a cylinder that has been honed, after about 10 ounces of fuel run through the engine. Because the moving surface always wears less than the static surface, this may be the reason the rings do not wear out quickly and the reason the cylinders need to be a lot harder than the rings. Just a thought.

The 180 cc engine that Jack speaks of is mine. It had nearly 20 gallons of fuel thru it and the rings still wouldnt seat. It is a two ring motor. It was very difficult to start due to very low compression. I dont claim to know much about the coatings and what not of two stroke cylinders but I do know this. After jack honed my cylinders the engine became a monster and was way more reliable and easier to start.

Scott

Originally Posted by sjmorgan

The 180 cc engine that Jack speaks of is mine. It had nearly 20 gallons of fuel thru it and the rings still wouldnt seat. It is a two ring motor. It was very difficult to start due to very low compression. I dont claim to know much about the coatings and what not of two stroke cylinders but I do know this. After jack honed my cylinders the engine became a monster and was way more reliable and easier to start.

Scott

Thanks Scott for some facts about this subject.
Jack

Originally Posted by rcign

Diamond is the hardest substance on the planet...It takes a diamond hone to make the surface of a hard chrome or nikasil surfaced cylinder smooth enough to be used with cast iron piston rings..
Maybe some of you experts can tell me how cast iron rings could be expected to smooth a rough cross hatched surface....If the surface was not honed smooth from the factory...
Anyone ????

its the moly propenents reampilifying the 3.14 factors in a flux vertical swash,
need i digress?
hey you said anyone

Touche"