Jump to content

- - - - -

Duplex Vernier Pulley And Chain Tensioner

  • Please log in to reply
6 replies to this topic

#1 andyt


    Speeding Along Now

  • TMF+ Member
  • PipPipPipPipPip
  • 327 posts
  • Location: Melksham
  • Local Club: cooper register

Posted 31 December 2018 - 11:29 AM

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.

#2 Steve220


    Up Into Fourth

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 3,774 posts
  • Location: Shropshire
  • Local Club: RAF Mini Club

Posted 31 December 2018 - 11:35 AM


#3 Rorf


    Super Mini Mad

  • Members
  • PipPipPipPipPipPip
  • 576 posts
  • Location: Cape Town

Posted 31 December 2018 - 02:22 PM

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

#4 Cooperman


    Uncle Cooperman, Voted Mr TMF 2011

  • Mini Docs
  • PipPipPipPipPipPipPipPipPipPipPip
  • 21,280 posts
  • Location: Cambs.
  • Local Club: MCR, HAMOC, Chelmsford M.C.

Posted 31 December 2018 - 02:26 PM

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.

#5 neal


    Speeding Along Now

  • Members
  • PipPipPipPipPip
  • 318 posts
  • Location: Leicestershire

Posted 31 December 2018 - 04:43 PM

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

#6 Moke Spider

Moke Spider

    Crazy About Mini's

  • TMF Team
  • PipPipPipPipPipPipPipPipPipPip
  • 8,810 posts
  • Location: NSW
  • Local Club: South Australian Moke Club

Posted 31 December 2018 - 05:40 PM

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.

#7 Racer_Pete


    Up Into Fourth

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPip
  • 2,482 posts

Posted 31 December 2018 - 06:03 PM

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

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users

Mini Spares