5 replies to this topic

[sam7]

hi,

i have a 1380 engine with a twin duplex chain, but it never had a tensioner fitted, so was just reading through a engine project and the guy had the same set up as me. and he had fitted a tensioner.
are tensioners needed with a duplex chain??

funny thing is, i asked mini spares before fitting back together and fitting the engine back in. and they told me its not needed but now i kind of doubting it.

what do u guys think??? is it needed??

[Tupers]

You don't have to have one but keeping the chain tight will make it last much longer.

[sledgehammer]

I don't think they need one as the chain won't stretch as much -

but I'm sure they could be fitted if you can find a big enough chain slipper / tensioner foot

[sam7]

cool, thanks for the help. i had one from a old engine and ur correct it wasnt wide enough to fit both chains on.
chhers guys

[Cooperman]

The Duplex chain was originally fitted to the Mk.1 Cooper 'S' and it didn't have a tensioner.
On high-revving engines the tensioner can break up when revved high as the pad does not sit right across the chain but just bears on the chain centre. I've had engines to sort where the pad has completely broken up, but these were rally engines revved to around 7000 rpm. For engines kept below about 6000 rpm a tensioner could be OK, although it's not really necessary.

[JustSteve]

As cooperman said really. Only use one if it's a mild engine and you really are that fussed about the tiny amount of noise they reduce. The chain should never reach the condition that they are needed

I'm pretty sure most people keep them off. I won't be using one on my current engine build.