I've googled and searched youtube, but so far been unable to find any details about how the *new* (version "K") timing chain tensioner works.
The old timing chain tensioner appears to work thusly: it is driven by oil pressure, which causes it to push out a rod which pushes a plastic guide rail against the timing chain. When the engine is shut off, oil pressure goes to zero. Tension position is maintained with a pawl, held in place by a C-shaped piece of spring steel.
Q#1: How does the rachet mechanism in the new tensioner work? Is the spring wire simply a friction fit pawl (maintaining the position on the rod by gripping it with spring tension)?
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IIRC, oil pressure in an engine fluctuates (based on RPM, load, oil thicker during cold start, etc). So by using oil pressure to tension the timing chain, it seems like the tension would fluctuate as well. Although with the rachet mechanism, I suppose the tension is maintained at the level set by the highest oil pressure the engine sees.
Q#2: Wouldn't it be a better to have the timing chain tension maintained by a known fixed force (eg, via a spring-loaded tensioner such as is used in the serpentine belt)?
Thanks in advance!
The old timing chain tensioner appears to work thusly: it is driven by oil pressure, which causes it to push out a rod which pushes a plastic guide rail against the timing chain. When the engine is shut off, oil pressure goes to zero. Tension position is maintained with a pawl, held in place by a C-shaped piece of spring steel.
Q#1: How does the rachet mechanism in the new tensioner work? Is the spring wire simply a friction fit pawl (maintaining the position on the rod by gripping it with spring tension)?
----
IIRC, oil pressure in an engine fluctuates (based on RPM, load, oil thicker during cold start, etc). So by using oil pressure to tension the timing chain, it seems like the tension would fluctuate as well. Although with the rachet mechanism, I suppose the tension is maintained at the level set by the highest oil pressure the engine sees.
Q#2: Wouldn't it be a better to have the timing chain tension maintained by a known fixed force (eg, via a spring-loaded tensioner such as is used in the serpentine belt)?
Thanks in advance!
