Page 36 - Foton Workshop Manual - Auman EST-M

IN - 30 Introduction - Cleaning regulations

Cleaning regulations

1. Definition of cleaning
Be sure to remove the chippings from the parts, which may pollute the engine system, but it doesn’t mean that
the parts must be smooth. It’s unnecessary to grind the sealing gasket surface with sandpaper until it’s ground
to its factory machining mark, and it often damages its sealing effects. It’s very important to keep the limit of
surface finish and flatness to form the excellent sealing surface. The sealing gasket is used to fill up the
uneven part of special surface.
In case of adopting the molded edge sealing gasket, it’s usually unnecessary to grind the sealing gasket
surface with sandpaper. The molded edge sealing gasket is a sheet metal bonded with sealing material, and its
metal part forms a reliable junction of metal and metal.
It’s best to remove a small quantity of sealing material from the part with a blunt scraper, so you needn’t any
time to polish its whole surface with an automatic grinder or grinding wheel.
For those sealing gaskets with molded edges, almost all the sealing gaskets adopt some material containing
anti-sticking release agent. Of course, it’s not caused by overheat due to long-time installation of some sealing
gaskets or failure of release agent due to sealant application, so it’s easy to remove. However, our goal is not
only to remove the sealing gaskets, the matching surface of parts shall not be damaged, and it shall not pollute
the engine (don’t make small particles fall where they can’t be removed).
It’s unnecessary to blast-clean the piston crown until the black dirty spots are removed. It’s only required to
remove the carbon deposits from top rings and ring grooves. More information about blasting and piston
cleaning are later given in this document.
It’s not recommended to grind or mill the carbon ring on the top of cylinder liner via sandpaper until clean
metal can be seen. It will damage the cylinder liner or any fault in reverse indicating arrow (dust removing
mark) to do so. Remove the carbon ring for easier removal of piston. Only if its rated speed exceeds that of
power tool, high-quality medium-grade stiff wire wheel can cause the smaller damages at the same speed.
After removing the piston, look for the fractured steel wire carefully. However, the steel wire is easy to see,
and can be suck up with a magnet.
The oil on the part removed from the engine can absorb the dust of air. The dirt can be absorbed on the oil. If
possible, make the old oil remain on the part until it’s ready for cleaning, check and installation, and then
clean the part and remove the dirt from it. If the part is cleaned and placed in the open, clean it again before
the installation.
Ensure that the clean oil is used to lubricate the part and then it’s installed again. They needn’t be filled with
oil, but the oil must be covered on the moving parts (or a good pre-filling process of lubricating system is
required before towing the engine).
It’s not required to remove the paint from part surface by blasting. The part may be re-painted, so it’s required
to remove any peeled paint.
2. Grinding plate and sand paper
The keyword is “grinding”. The engine parts can’t be worn, i.e. all of them are locked together or slide over
each other. The friction materials and dust particles can reduce these two functions.
Caution
The oil duct and contact face of part moving must be keep clean, otherwise it will cause the failure of
bearings and liners, and lead to damages and failure of main parts over time, especially main bearing
and connecting rod bearing.
It’s not recommended to grind any assembled engine or part with sand cloth or sand paper, including but not
limited to removing the carbon deposit zone from cylinder liner or cleaning the surface or holes of cylinder
block.

IN-030