Cobra Y173V - Page 61

4. DISASSEMBLING AND SERVICING
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⑤Camshaft check
The camshaft is main driving part of the train valve mechanism, which control the intake and
exhaust valves opening and closing.
Feature: The shaft is equipped with cam and journal which can control intake and exhaust.
When operating, camshaft operating face and lifter will be badly rubbed from periodically
impacting and easily be damaged. So, the camshaft shall be wearable and lubrication well.
 Visually inspect camshaft face and camshaft height for
damaged, and camshaft and bearing for loosening and
wearing, replace as required.
 Check camshaft for height dimension, if out of the service
limit, replace the camshaft.
Standard
Service limit
27.70mm(IN)/27.75mm(EX)
27.45mm(IN)/27.50mm(EX)
 Check outside diameter of the camshaft, if less than the
service limit, replace the camshaft.
Standard
Service limit
13.965-13.990mm
13.915mm
Camshaft wearing cause and to engine performance influence：
Poor lubrication will result in camshaft abnormal wearing, such as, oil viscosity low,
impurity too much, and recycling oil little can’t let the camshaft surface forming complete oil
film to make the camshaft surface seriously worn in the high speed rubbing stat. Second,
installing precision problem, when the matching clearance of the camshaft journal and
camshaft seat or bearing is out of the service limit, camshaft rotation precision will lower and
contacting with the relative part produce deviation face to make abnormal wearing.