Piston engine problem Brisbane -

WORN OUT

Worn out pistons is a normal condition after a considerable amount of miles. The distance a piston may travel before it is considered worn out will depend upon several external factors. For instance a commercial cab for hire that is driven consistently at normal operating temperature will travel well in excess of what a stop start private commuter vehicle will. A couple of reasons help the commercial cab do a lot more mileage prior to pistons wearing out. The cab will generally be better serviced  and maintained to a tight schedule. The engine in the cab is seldom driven cold or under normal operating temperatures and as "the majority of engine wear occurs on cold starts" the cab is kilometres ahead of the private vehicle. Some service factors that can cause premature wear of pistons is air borne contamination with abrasives from poorly maintained air filters. This wear will be more noticeable in the piston ring grooves, rings and bores as they come in contact with the dusted air. ( when an engine fails from airborne contamination the term "A dusted engine" is used.) Abnormal piston skirt wear will result from "contaminated engine oil" and will be recognised by numerous vertical marks on the piston skirt and on the cylinder bore where the piston travels. This contamination can occur from a build up of wear practicals in the engine oil due to a lack of oil and filter changes. If an oil filter is left in service way beyond it's normal service life the filter can block up enough so the oil filter bypass valve operates letting contaminated unfiltered oil enter the oil galleries and damage most components. When new pistons are fitted to a newly bored engine the boring clearance specifications may be as low as 0.0005"...that is 5/10th. of a thousandth of an inch....so it is easy to see how important correctly filtered oil is to the life of the piston. This also makes final washing of re- machined and re-honed engine components so critical during an engine rebuild. (honed bores must be washed with hot soapy water and re-checked until spotless) Disclaimer Agreement : Every care has been taken in writing this information and procedures, but no responsibility can be excepted for errors, omissions or misuse of this information and procedures. The information available on this site is for your instruction only and cannot be copied for sale, © copyright 2001 UMR Engines