Timing Chain Tensioner

The Rolon item with the Allen key bolt, and the slipper pad the same size as the slipper base:

The Renold item - no Allen key bolt, and the slipper pad goes over the ends of the slipper base. However the Renold name is stamped in the reverse direction to mine and would be upside down when fitted:

Another Renold item with a location dowel in the oil supply port, and plastic shipping spacer which is removed once installed with the chain. Also showing the spacer plate for use with single-row chains, and the gasket, which all tensioners should be supplied with:

Peter King's advertised as 'Not Rolon', but with the large oil feed hole instead of the drilled dowel:

More worryingly (despite the plastic shipping spacer) no makers name at all, and the face showing it may have been ground off:

This looks like a failed Renold item from the part of the name that is visible, and the slipper pad overlapping the ends of the backing. The slipper pad has come off the backing and allowed the backing plunger to come out of the body, potentially very damaging if it happens at speed. However the identification marks are upside down and the overlap is triangular rather than rectangular as with the Renold item above:

A Rolon item with the plastic shipping spacer, same length slipper pad as slipper base, and obviously no dowel on the back:

An alternative design, this from Denis Welch Motorsport at £130, even more expensive from SNG Barratt and SC Parts:

NOS BL slippers can be substituted for those that come with Rolon tensioners:

Bee's tensioner before removal ...

... Renold type - name under the lock-tab strip, no Allen key bolt, oil-way dowel on the back but with a smaller hole than above:

Slipper pad fully overlapping the ends of the slipper base:

Note the piston is offset behind the slipper pad, which puts it slightly offset one way to the single chain and slightly the other way to the duplex, so only one tensioner is needed for both types of chain:

Stepper mechanism with entry slot arrowed ...

... limit teeth along the helix ...

... recess to lock the mechanism in position for installation ...

... and slot so the mechanism can be pushed and twisted into place with a screwdriver against spring pressure.

Spring ...

... peg (A) that passes through the entry slot and latches behind each tooth, and chamfer (B) to direct oil from the inlet to the open end of the tube on the slipper:

Slipper pad barely worn, with hole through from piston to lubricate the chain:

Reassembled - mechanism and spring fitted ready for insertion to body ...

... and slipper fully inserted ready for fitting to engine. Once mounted push the slipper back the remaining amount and it will pop forward to tension the chain. If you push the slipper back any further before mounting, the mechanism will rotate and the peg move from the locking position into the helix, and the slipper, mechanism and spring will fly out: