EXTRA

INFO

EXTRA INFORMATION PAGE

This page is to give mechanics and everybody for that matter a better insight into how to tell more from engines when you are stripping them to find a problem or also things to look for when rebuilding an engine.

Cam Effect (Ridge Wear)

Whenever a four-stroke engine has accumulated around 60,000 running hours or more, then its crank pins are in all likelihood affected by what is called the “cam effect” or “ridge wear”.

This phenomenon develops over time and manifests itself in an uneven wear pattern that is, with the right tools, easily detectable as a protruding band (“cam”) that goes around the circumference of the crank pin. It usually only develops on engines equipped with grooved bearing shells and its development is a function of time. The more impurities (abrasive particles) the lubricating oil contains, the faster the cam effect develops.

The two major makers of medium-speed diesel engines, MAN Diesel & Turbo and Wärtsilä, have booth issued Service Letters to make their customers aware.

We offer a crankshaft polishing service which is required to repair this effect , here is a link to more information on our Crankshaft services - https://sites.google.com/s/1R0SAe58aNXsVREzWRX4N2n63TksQNWcg/p/1jEZl81CGjp-yFDmAPOVtF6_sBnl8lOan/edit

VALVE STEM SEAL FAIL

This picture shows excessive valve stem seal failure. This has caused a massive build up of a oily carbon material which eats into the valves seating edge. A head with this type of valve will definitely need valve stem seals , valves re seating and maybe some valve guides or seats.

BURNT VALVE

The red circled area in the picture shows where a valve has burnt through. This normally happens due to excessive oil in or around the valve area , age , fuel mixture or fuel quality. This burnt valve would cause a massive loss of compression and a non firing cylinder. This would require at least one valve and re seating and maybe even a new seat.

FUEL MIXTURES

This picture is a great quick reference for how the engine you are working on is running. There is a massive difference on fuel consumption , performance and engine life depending on the quality of the fuel used and / or the fuel to air mixture. If the engine is running lean it can also lead to more comprehensive damage to both the cylinder head and block.

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