6 replies to this topic

[andyt]

I'm swapping the simplex timing gear for a piper duplex vernier timing Gear do you still use the chain tensioner? It's a 1275 A+ engine.

[Steve220]

No.

[Rorf]

You can if you wish, many engine builders on this forum advocate it too

[Cooperman]

You can, but it causes the tensioner pad to take a single load on the chain centre line insteas of on each edge of the pad.
It it not necessarily an issue, but I have seen a couple of broken pads on high-revving engines.

[neal]

The duplex chain made by 'IWIS' apparently is good, not sure if this comes as standard with the kit but can be bought separately.

[Spider]

I fit the Tensioner with the Duplex Chains. Probably not necessary per se, but when you check how 'tight' they hold Cam Timing after the engine has a good few miles up, particularly at low engine speeds, it is 'tighter' with the Tensioner. This can be seen with an Ignition Timing Light (though there can be other reasons for scatter here).

 

Just be sure to knock the dimple on the cover out when using a Duplex Chain. It's at about the 4 O'clock position, if it has one.

[Racer_Pete]

I don't, but allow 2degrees of chain stretch on a new chain if you don't.