Timing chain tensioner
Turbo Mini Forums

Do you need a timing chain tensioner on a Duplex Vernier system?

If not, why not?

You don't need it, but if you fit it it'll only help...

I wanted to know the same a while ago and found this.
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=2175
Seems opinions vary but overall I decided yes, and fitted one.

Schrödinger's cat - so which one am I ???

Aha! Nice one thanks. :)

If you have the parts,fit them, it cant do any harm.I have done this more than once and never had a problem, or any chain noise,ever.

I've just replaced the 38 year old 80k mile duplex chain on the Midget that British Layland fitted, and I was quite surprised just how much it had stretched. I reckon there that there was enough slack to allow the cam to be rotated about 3 or 4 degrees in either direction.

EDIT: However I did not fit a tensioner as there would have required me fabricating a custom front plate but I will check the the chain before the engine gets to 160k mile.

Edited by Rob H on 14th Feb, 2009.

I,ve heard this comment about needing to modify the front plate to fit a tensioner before and I dont understand it. I have always fitted tensioners to duplex kit (I,m a belt and braces type, I suppose ) and I have never needed to modify a front plate on any Midget/Marina or Ital engine I have done- just lucky I guess .Point to bear in mind is not to apply more than very slight tension or they whine like a bastard !!