CHAIN INSPECTION AND REPLACEMENT

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CHAIN INSPECTION

The chain should be inspected at every crankcase inspection and also whenever any irregularities are noted. E.g. noise or vibration.

Items that require particular attention:

•              l.o. pipe and sprayer connections.

•              chain wheel teeth both on profiles and flanks.

•              adjustment arrangement security.

•              play in free length of chain.

•              condition of chain especially for cracks in rollers and side plates.

•              dampers and bump bars for security and damage.

NB      Any adjustment of the chain tension will effect the camshaft timing and this must be attended too at the same time. Adjustment of the camshaft as a whole can usually be carried out by relative movement of the camshaft coupling to the chain wheel.

CHAIN REPLACEMENT

Two methods are common :

1.            Complete removal of old chain from chain casing before installation  of new chain. Engine stationary throughout operation.

1.            Attachment of new chain to split link of old chain then fed onto chainwheels by engine rotation.

Complete removal of old chain.

•              slacken off adjustment device.

•              take load off chain in way of splitting point.

•              split chain by jacking out a pin link so that the chain hangs freely over camshaft chain wheel.

•              lift chain clear through top opening using engine room crane taking care the free ends do not foul (use chain blocks to guide free lengths)

•              lower new chain in so that it engages on camshaft chain wheel and guide free ends past idlers, jockeys, etc.

•              using chain block haul free end under and around crankshaft chain wheel.

•              bring free ends together and fit joining link.

•              adjust chain tension

•              check timing and adjust as necessary.

Feed new chain into position connected to end of old chain.

•              undo adjustment device.

•              take load off chain in way of splitting point.

•              split chain by jacking out the pin link to be removed

•              connect upper end of old chain to new chain.

•              connect other end of old chain to chain block outside of chain case.

•              turn engine until new chain is fed in and disconnect from old chain .

•              connect chain at joining link

•              re-adjust tension.

check camshaft timing and adjust as necessary