Machinery Lubrication

Machinery Lubrication Jan Feb 2016

Machinery Lubrication magazine published by Noria Corporation

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Figure 2. The sequence of piston ring-pack deposit formation ML PUBLISHER Mike Ramsey - GROUP PUBLISHER Brett O'Kelley - EDITOR-IN-CHIEF Jason Sowards - SENIOR EDITOR Jim Fitch - TECHNICAL WRITERS Jeremy Wright - Wes Cash - Alejandro Meza - Bennett Fitch - Michael Brown - Garrett Bapp - CREATIVE DIRECTOR Ryan Kiker - GRAPHIC ARTISTS Patrick Clark - Terry Kellam - Josh Couch - Greg Rex - ADVERTISING SALES Tim Davidson - 800-597-5460, ext. 224 MEDIA PRODUCTION MANAGER Ally Katz - CORRESPONDENCE You may address articles, case studies, special requests and other correspondence to: Editor-in-chief MACHINERY LUBRICATION Noria Corporation 1328 E. 43rd Court • Tulsa, Oklahoma 74105 Phone: 918-749-1400 Fax: 918-746-0925 Email address: MACHINERY LUBRICATION Volume 16 - Issue 1 January-February 2016 ( USPS 021-695) is published bimonthly by Noria Corporation, 1328 E. 43rd Court, Tulsa, OK 74105-4124. Periodicals postage paid at Tulsa, OK and additional mailing offices. POSTMASTER: Send address changes and form 3579 to MACHINERY LUBRICATION, P.O. BOX 47702, Plymouth, MN 55447-0401. Canada Post International Publications Mail Product (Canadian Distribution) Publications Mail Agreement #40612608. Send returns (Canada) to BleuChip Interna - tional, P.O. Box 25542, London, Ontario, N6C 6B2. SUBSCRIBER SERVICES: The publisher reserves the right to accept or reject any subscription. Send subscription orders, change of address and all subscription-related correspondence to: Noria Corporation, P.O. Box 47702, Plymouth, MN 55447. 800-869-6882 or Fax: 866-658-6156. Copyright © 2016 Noria Corporation. Noria, Machinery Lubrication and associated logos are trademarks of Noria Corporation. All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of Noria Corporation is prohibited. Machinery Lubrication is an independently produced publication of Noria Corporation. Noria Corporation reserves the right, with respect to submissions, to revise, republish and authorize its readers to use the tips and articles submitted for personal and commercial use. The opinions of those interviewed and those who write articles for this magazine are not necessarily shared by Noria Corporation. CONTENT NOTICE: The recommendations and information provided in Machinery Lubrication and its related information properties do not purport to address all of the safety concerns that may exist. It is the respon - sibility of the user to follow appropriate safety and health practices. Further, Noria does not make any representations, warranties, express or implied, regarding the accuracy, completeness or suitability of the information or recommendations provided herewith. Noria shall not be liable for any inju - ries, loss of profits, business, goodwill, data, interruption of business, nor for incidental or consequential merchantability or fitness of purpose, or damages related to the use of information or recommendations provided. Machinery Lubrication 5 caused by valve guide wear and seals that are worn, cracked, missing, broken or improperly installed. The engine may still have good compression but will burn a lot of oil. Oil Flow Through the Piston Ring-pack Engine oil is designed to produce an oil film on the cylinder walls. While the oil control ring on the piston squeegees much of it off, a thin film will still remain. When the engine decelerates, high negative pressures suck oil in the combus- tion chamber and out the exhaust manifold. The problem is more pronounced when rings or cylinders are badly worn or damaged, but it can also occur if the cylinders were not honed properly (out-of-round or surface finish defects) when the engine was built (or rebuilt) or if the rings were installed improperly. Much of the oil that is transported through the piston ring-pack and along the liner usually occurs during the compression stroke. The oil control ring scrapes the oil from the cylinder wall. The scraped oil flows to the ring drain holes/cavities. Oil left behind on the cylinder wall is needed to lubricate the compression rings. Once oil moves past the compression rings, it is difficult for the oil to return to the sump. However, blow-by gases can provide a transport medium to help recycle the oil back to the sump (see Figure 1). Piston Ring-pack Deposits and Movement Piston ring-pack deposits can sharply reduce ring movement and flexing. Likewise, ring move- ment can greatly influence where deposits form and the lubricant motion (transport) within the ring-pack. This ring motion defines the resi- dence time of the lubricant in the ring-pack, which in turn affects the rate of lubricant degra- dation and where deposits will form (see Figure 2). Ring-pack temperatures can range from 195-340 degrees C. Collectively, these conditions can accelerate piston-ring-liner (PRL) wear, impair combustion efficiency, increase blow-by and reduce oil economy (more oil consumption). One way this happens is through carbon jacking. In this phenomenon, carbon buildup occurs in the ring grooves (fed by soot and oil degradation prod- ucts). The corresponding ring movement restriction increases wear, blow-by and oil consumption with the rhythm of the piston. Cylinder Wall Oil Evaporation As much as 17 percent of total oil consump- tion is associated with liner wall evaporation. The more distorted (out-of-round) and rough (surface finish) the cylinder liner, the more oil film that will remain on the liner after the power stroke. High liner surface temperatures (80-300 degrees C) will cause a loss of this oil by misting and evaporation. Light oil molecules are more prone to evaporation. These light molecules are the first to deplete, and as a result, there is less evaporative loss toward the end of the lubri- cant's service interval. Not all oils of the same viscosity are equal from the standpoint of volatility (risk of evapo- rative loss). Some lubricants may exhibit as much as a 50-percent greater loss from vola- tility than others. This is influenced by the base Oil Thermal-oxidative degradation Volatiles (evaporation) Deposits

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