17 replies to this topic

[austinmini1963]

Hi, I recently bought a 1293cc engine (block pistons cam and lightened duplex timing chain.) and have an a+ 1275 auto I am taking bits off of for the 1293.
The 1293 has no chain tensioner but the 1275 does, is it worth me taking it off and fitting to the 1293? It is a little narrower though.

Many thanks, Tom

[Stiggytoo]

I believe the general consensus is that the tensioner will wear relatively fast and break apart.

[KernowCooper]

It runs on the centre of a duplex so not spanning the whole chain, some run them some dont I have one on my duplex when it was built some 3000miles ago

[ACDodd]

Every engine I build has one.

 

AC

[austinmini1963]

Ok thanks, I will fit it to the engine. Do they do a full width one for the duplex chain, or is it just one for all?

[Ethel]

No, duplex chains were never fitted with tensioners by the factory, all A+'s used single chains.

[austinmini1963]

The duplex chain is definately not standard, so would you definately recomend fitting the tensioner or not?

[ACDodd]

I fit them to every engine, there is only one type.

 

AC

[welshdan]

On the last build i did, i used a tensioner. I believe it is not required. The tensioner just wore badly. An engine i did a few months ago doesnt have one, it runs very well without issues. My latest build doesnt have one either. In reality i dont think it makes a difference

[Cooperman]

I have re-built one engine on which the tensioner pad had broken up and one which was about to. Both were high-revving engines with Duplex chains and I put it down to the fact that the tensioner was only bearing on the centre between the two sides of the chain. However that is just an assumption and it could be coincidental.

Remember, the original Cooper 'S' had the duplex chain and no tensioner.

I think it's personal preference.

[Mrpeanut]

I fit them to every engine, there is only one type.
 
AC

Out of interest, why do you consider it necessary with a duplex?

[KernowCooper]

Any timing chain eventually will stretch and the tensioner keeps the valve timing accurate besides the noise they make when worn, obviously the duplex is stronger but eventually will show a bit of noise and wear. And remember the distributer is driven by the camshaft so it prevents timing scatter and gives more accurate ignition timing through out the range

[ACDodd]

Valve and ignition timing stability. No issues even at 8krpm.

 

AC

Edited by ACDodd, 14 October 2013 - 09:45 PM.

[Mrpeanut]

Cheers. I was going to run my rebuild without one, not now!

[welshdan]

due to the rotation of the engine wont the chain be taught between the sprockets keeping timing in check?

 

also use a good quality chain.