Cylinder liner honing
Cylinder liner honing
(OP)
I understand that honing of cylinder liner is not a routine work. Can someone tell me when it is necessary to hone a cylinder liner? And what is the correct procedure for honing a cylinder liner? Regards - wr





RE: Cylinder liner honing
RE: Cylinder liner honing
Procedures for honing can be found all over the internet or buy a book. Honing procedure varies with material and desired surface finish which all depends on application.
RE: Cylinder liner honing
Most ductile iron or hardend steel (nitrided) liners are honed with a "plateau" honing technique. They are first honed with a relatively coarse stone to true-up the bore. The coarse stone leaves microscopic 'peaks" and "valleys" in the liner surface. The bore is then finish honed with a relatively smooth stone, which knocks off the "peaks" but leaves "plateaus" and shallow "valleys".
The theory is that the rings will glide against the "plateaus", while the "valleys" will provide little lubricant reservoirs. Nikasil/aluminum liners supposedly work in the same manner.
Regards,
Terry
RE: Cylinder liner honing
You used the term "liner". If this indicates a replaceable liner (sleeve), such as that used in a heavy duty diesel, they are not commonly honed. When the engine is torn down, new liners and pistons are installed.
The correct procedure for honing should be obtained from the ring supplier, and executed as well as possible, given the equipment available. Factory hone quality can be closely approximated in a good automotive machine shop.
RE: Cylinder liner honing
Thanks for your responses. Yes, it is a liner that is replaceable in a medium speed diesel engine. The liner is still within the wear limits but new piston rings will be installed, is it necessary to hone the liner in this case using a honing brush ? Regards WR
RE: Cylinder liner honing
.................
I'm not sure what you are asking and why, it depends what car and what year you are working on/talking about. If you are doing a nominal overhaul perhaps using original pistons and new (first rebuild rings) which should be about .002" oversize you would use a "bead hone" to de glaze and adjust for minor taper. A more precise honing can be achieved using a rigid cylinder hone and can substitute for the bead hone which is mostly used for de-glazing as mentioned above. If the cylrs have been bored the rigid cylinder hone will be used with successive finer grits.
The bead hone labor process is included when giving quote for a minor overhaul as is the rigid cylinder honing if it's just use to de-glaze the cylinders; however; if things are worn beyond specifications and require more time then there may be an additional charge. Machine shops will usually include the honing process if they give a quote for boring. Like all things, it depends on the skill of the mechanic who knows how to do the best possible job.
As mentioned above it's very important to know the year and design of the engine in question for metallurgy has changed in the last 15 years. The piston and ring fitting clearances have changed dramatically and without consulting a professional it should not be undertaken until you know what you are doing if this is to be a home repair / rebuild.
Cheers,
GTM2U
RE: Cylinder liner honing
Let me give you some more information about this engine; it used for power generation, it’s output power is 3.85 MW, arranged with 16 V- type cylinders, rotating at 720 rpm and having bore diameter of 280 mm. As mentioned above, all liners are replaceable and therefore, neither machine shop nor boring would be required because if a liner is out of wear limits it would simply be replaced for a new one. The situation now is that all liners are still within wear limits and therefore would not be replaced but all piston rings will be replaced for new ones. Now, would the liners require manual honing before installing the pistons and piston rings as a routine work? or are there some measures / indications that determine the necessity of such honing. Please note that we mean by manual honing is that type of honing carried out at site using a honing brush driven by electric drill. Regards WR
RE: Cylinder liner honing
Sorry - I couldn't find the name of a manufacturer but I bet a rebuild shop would know. I don't know wheter a 280mm dia tool exists.
A colleague did a lot of durability work with a few engines some years ago with limited funding. Re-ringing following flexi-honing did a good job and oil consumption tended to improve.
RE: Cylinder liner honing
John
RE: Cylinder liner honing
RE: Cylinder liner honing
Sounds like a serious engine you're rebuilding! Is it a marine or rail unit? What were the symptoms that led you to inspect the cylinders and re-ring? Let us know how it goes.
RE: Cylinder liner honing
Conventional honing does not correct any out-of-round condition in the cylinder bore. It is used purely to provide the proper surface finish to achieve good ring seating.
When re-ringing, it is done to de-glaze the cylinder, again to permit good ring seating.
RE: Cylinder liner honing
RE: Cylinder liner honing
RE: Cylinder liner honing
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Cylinder liner honing
RE: Cylinder liner honing
I work in a maintenance section of a Natural Gas Pipeline in the US and we use 2000Hp (1.4MW) natural gas engines and smaller for compression. My experience is that we use the flex-hones (beri-brush) on cast liners to create a "hatch" surface to break in the rings on our 4-stroke spark ignited engines. On our 2-stroke engines, some are cromed liners which are too hard for honing, the rest have oil injection systems in the power cylinder bores which seem to reduce the need for the initial break in procedures that a 4-stroke needs. Again, as our engines are spark ignited I'm not sure how this compares to your diesel. With your higher compression and sealing loads, you may be back to needing the break-in surface, that our four strokes need.
This information is what has been handed down from the older guys here, so acuracy should be checked. I have been meaning to contact some of our piston, ring, and liner vendors as well as the OEM's and get some more up to date information. Does your ring vendor have an opinion? A person should be careful, but our vendors and OEMs have been my best source of information. If they give me good information, I keep buying from them.
What is the make and model of your engine? Where in the world is it located? Is this an in-frame overhaul? Is this a emergancy, peaking, or base-load, genset.
Just to give the auto guys some scale, these are 11" pistons on a 5100 Hp genset.
RE: Cylinder liner honing
Tim
RE: Cylinder liner honing
htt
-----------------------------------------
"rigid" hones like these at Sunnen can correct out-of-round, taper etc. (Or, if impropely used, introduce taper or bell-mouth or barrel).
http://w
RE: Cylinder liner honing
Tmoose, have you used these "rigid" hones on a 15.25" diameter bore? (387 mm) I'm preparing to do an overhaul on one of our integral compressors, this summer. I plan to use a rigid hone to knock the ring ledge out of the liners, provided they are in spec. Any advice?
I agree that the beri brushes don't do much, but if you are changing your piston, rings, or bearing 20% of the way through your overhaul cycle, you need something to break the glaze and get the rings to seat. Or am I not thinking about this correctly?
Thanks, dwedel