CAM CHAIN TENSIONER ,COMPARISON OF OLD & NEW

[firestorm 69]

I changed the front cylinder CCT today due to excessive rattling & while I had them side by side I thought I would have a close look at them.This is what I found:

OLD CCT (pink dot):
free length 67mm ( due to weakened spring )
tensioner internals loose & rattly
occasionally able to push plunger back into body due to worn ratchet

NEW CCT(orange dot):
free length 70mm
much closer fit of internals
spring material appeared to be different
unable to compress plunger once extended

It seems as though there is more than one issue causing these tensioners to slacken, but obviously even if the spring is intact( as mine was),if the internals are worn & loose then you might find that the ratchet could slip causing chain rattle.
This is exactly the symptom that mine displayed, an intermittent rattle which came & went with no obvious pattern.

p.s. I got my new tensioner from David Silver spares & can't fault thier service.

Cheers dudes

[LotusSevenMan]

FS69.
Glad you caught it in time.

Re. Ratchet? There is no ratchet (as in like automatic handbrake tensioners that self adjust up but can't go back unless manually released). These CCT's are sprung loaded but can 'float' back and forth under spring tension to allow for cam chain whip. They faithfully follow the chain movements while still maintaining adequate tension.
Sirch on this site has done some extensive research with a video camera on the cct's ( )with marker indicators showing how they go in and out with acceleration/overun situations.
It is the weakened spring that creates the problem by allowing the cam chain to retract the plunger too much and thus the thrashing/ticking sound that precedes total failure.

[LotusSevenMan]

Yep!
Internals are the same whatever the dot colour (orange, purple etc). It is a quality control mark and not indicative of changes to spec.

[robvtr]

I changed the front cylinder CCT today due to excessive rattling & while I had them side by side I thought I would have a close look at them.This is what I found:

OLD CCT (pink dot):
free length 67mm ( due to weakened spring )
tensioner internals loose & rattly
occasionally able to push plunger back into body due to worn ratchet

NEW CCT(orange dot):
free length 70mm
much closer fit of internals
spring material appeared to be different
unable to compress plunger once extended

It seems as though there is more than one issue causing these tensioners to slacken, but obviously even if the spring is intact( as mine was),if the internals are worn & loose then you might find that the ratchet could slip causing chain rattle.
This is exactly the symptom that mine displayed, an intermittent rattle which came & went with no obvious pattern.

p.s. I got my new tensioner from David Silver spares & can't fault thier service.

Cheers dudes

I would have thought that good old honda (knowing the cct history) have made generic slight mods to try and solve the problems

Rob

[firestorm 69]

I agree the colour coding is probably not significant, but may be indicative of different batches or periods.
On the subject of comparing internals I stopped short of dismantling my cct's, but there was signiificantly more slack / wear in the old one,as you might expect.
I've just dug my old cct out of the bin & I stand corrected about there being a ratchet.
If you hold a cct in your hand, try to compress the plunger into your palm. I could not get the new one to retract at all, but doing the same with the old one,sometimes it felt solid, other times it would suddenly slip,giving the impression of a worn 'ratchet' mechanism.
This might be down to the worn screw thread inside the tensioner binding then moving.
Any way the rattling has disappeared....game on !