Primary Chain Tensioner

From Citroen SM Wiki
Revision as of 17:14, 22 December 2011 by Brodule (talk | contribs) (Tension side)

There are several options for the primary chain tensioner, from the original spec to various levels of replacement.

This is an attempt to lay out all the options in one place so that you can tell what you have, what the weaknesses are, what you might wish to change to, and how to do so.

Note -- If the owners of photos of the various tensioners ship me copies, I will be happy to integrate the images into this page so that you can see what each looks like. Brucem 00:11, 1 August 2008 (EDT)

Regardless of which is selected, be sure to consider a chain oil spray as described in Primary Chain Oil Spray.

Also, fit an Air Conditioner Cutout.

Tension side

Chain limiters, original version on the left and Renold/Brodie version on the right
  • Original Chain Limiter
    • * Flat guide
    • Strongly recommended to be replaced with the Renold later design version as shown.
  • Citroen factory approved recommendation
    • * Curved Fixed Limiter
    • Available from [Brodie Engineering] or OOTFAB Marketplace:OOTFAB
    • Not essential to re-time cams when fitting this. Valve timing only advanced approximately 1.6 degrees.
Manufacturer drawings of modifications

Original Tensioner

Original tensioners, first version on the left and revised version on the right
  • Small curved pivoted shoe held against the chain by a scissor type ratcheting tensioner
  • Two fitment types of tensioner and moving shoe. Renold modification suggests a third
  • Pros/Strengths
    • (Obviously) no modifications necessary to install or replace
    • Once curved fixed limiter is installed, this is sufficient
  • Cons/Weaknesses
    • (fill me in)

Merak Tensioner

  • True hydraulic with ratchet & spring back-up
  • Pros/Strengths
    • Can be used with Curved fixed tension side limiter without modification
  • Cons/Weaknesses
    • Excessive wear on chain, Mk1 needs modifying to Mk2 staus, very expensive, requires engine modification, requires care when setting cam timing, does not prevent chain vibration on it's own, does not prevent straight limiter on tension side being knocked off by vibrating chain.

DS Tensioner

  • Spring tensioner with hydraulic spray through shoe
  • Pros/Strengths
    • Provides precisely metered chain oiling without drilling 0.5mm holes in block. All steel design is more robust than OE plastic ratchet. Eliminates "leading shoe" chain tensioner for more consistent tensioning as chain wears.
  • Cons
    • Requires drilling oil feed hole and drilling/tapping mounting holes in block

DS tensioner and OOTFAB type 1 curved fixed limiter - photo: John Titus

JBM Tensioner

  • True hydraulic(?)
  • Pros/Strengths
    • (fill me in)
  • Cons/Weaknesses
  • Is this still available?
    • (fill me in)