HONING
Before honing, the coke deposits and the Ridge formation are removed by scraping. The honing is made by means of a flex honor (honing brush) with fineness grains 80 to 120. Revolution speed between 80 to 160 RPM is chosen. In order to achieve the required angle between the honing grooves the vertical speed is adjusted to about 1 metre per second for one move. The procedure is to be continued until about 25% of the surface is covered by honing grooves. This is achieved only after a few vertical movements. Gas oil should not be used as it promotes scratches and uneven surface roughness. After the honing, the liner is carefully cleaned and it must be ensured that the all abrasive particles have been removed.
RUNNING-IN
The running in process is a prerequisite for the reduction of adhesive wear, and it enables proper gas sealing and lubrication.
When the liner is new, it is very rough(surface asperities) and the ring is not at embedded. Consequently there will be no proper Sealing, risk of blowby is substantial, leading to disturbance of the oil film and adhesive wear. Also the hot gases due to blow by break the lube oil film and this results in ring sticking which leads to adhesive wear and ring breakage.
Some engine manufacturers recommend using the straight Mineral oil without additives like the crankcase lubricating oil for cylinder lubrication during running in. The unneutralised acids help in faster wear (hence bedding) also.
Under reduced power, if regular cyl oil with High TBN is used, the unconsumed alkaline additives might form sticky deposits leading to ring sticking.
For running in purpose a profile ring such as KNP profile ring or minute ring is used, whose ring pressure is 1/5th of the conventional ring.
The engine is run at 10%MCR for 6hrs, then 24%MCR for 2hrs.... In this way increase the load to 100%MCR for 24hrs.
Before honing, the coke deposits and the Ridge formation are removed by scraping. The honing is made by means of a flex honor (honing brush) with fineness grains 80 to 120. Revolution speed between 80 to 160 RPM is chosen. In order to achieve the required angle between the honing grooves the vertical speed is adjusted to about 1 metre per second for one move. The procedure is to be continued until about 25% of the surface is covered by honing grooves. This is achieved only after a few vertical movements. Gas oil should not be used as it promotes scratches and uneven surface roughness. After the honing, the liner is carefully cleaned and it must be ensured that the all abrasive particles have been removed.
RUNNING-IN
The running in process is a prerequisite for the reduction of adhesive wear, and it enables proper gas sealing and lubrication.
When the liner is new, it is very rough(surface asperities) and the ring is not at embedded. Consequently there will be no proper Sealing, risk of blowby is substantial, leading to disturbance of the oil film and adhesive wear. Also the hot gases due to blow by break the lube oil film and this results in ring sticking which leads to adhesive wear and ring breakage.
Some engine manufacturers recommend using the straight Mineral oil without additives like the crankcase lubricating oil for cylinder lubrication during running in. The unneutralised acids help in faster wear (hence bedding) also.
Under reduced power, if regular cyl oil with High TBN is used, the unconsumed alkaline additives might form sticky deposits leading to ring sticking.
For running in purpose a profile ring such as KNP profile ring or minute ring is used, whose ring pressure is 1/5th of the conventional ring.
The engine is run at 10%MCR for 6hrs, then 24%MCR for 2hrs.... In this way increase the load to 100%MCR for 24hrs.
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