23 replies to this topic

[PACINO]

Cheers Spider. So....yes it's a better option to fit a tensioner. Tomorrow I will ask MED to see what they say me. Although I also remember that the Mk1 Cooper S had a duplex chain and it had not 'tensioner'. Also, I've read here that with douplex chain after 15K miles the mismatch can reach one degree and a half.

[bpirie1000]

TIME to make a decision.......

TO TENSION, OR NOT TO TENSION. THAT IS THE QUESTION.!!!!

[PACINO]

TIME to make a decision.......

TO TENSION, OR NOT TO TENSION. THAT IS THE QUESTION.!!!!

ha ha! That's true.

[nicklouse]

Cheers Spider. So....yes it's a better option to fit a tensioner. Tomorrow I will ask MED to see what they say me. Although I also remember that the Mk1 Cooper S had a duplex chain and it had not 'tensioner'. Also, I've read here that with douplex chain after 15K miles the mismatch can reach one degree and a half.

Well they don’t do a cover that can use a tensioner…..

[PACINO]

Later, they said me: "The pad of the standard tensioner does not fit the full width of the duplex chain, which can cause premature failure".

*I hope this may be useful to other people.

Regards
Luis

Attached Files

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Edited by PACINO, 01 February 2023 - 05:31 PM.

[Cooperman]

On the subject of chain stretch, I measured the stretch after 1500 miles with a new untensionered duplex chain and it had retarded the cam timing by 1.5 degres. However, this is the initial stretch and after that it settles down and reaches around 2 degrees of retardation by about 10,000 miles. 

With my high-revving 'S' engine I change the chain before that mileage.

Of course, the chain will still stretch with or without a tensioner, so always time in the cam a nominal 2 degrees advanced from the cam manufacturer's recommendation in order to optimise the cam timing over the life of the chain.

[PACINO]

Thanks for the advice Cooperman. Yes, I had read that recommendation of yours before. I will say so to the person who is going to build the engine for me.

Cheers
Luis

[Spider]

Cheers Spider. So....yes it's a better option to fit a tensioner. Tomorrow I will ask MED to see what they say me. Although I also remember that the Mk1 Cooper S had a duplex chain and it had not 'tensioner'. Also, I've read here that with douplex chain after 15K miles the mismatch can reach one degree and a half.

 

Neither the Simplex nor Duplex 'need' a tensioner to work. I think most other engines do, but the A and A+ don't. At various times in production, tensioners were fitted to the Simplex sets, but not always. None of the Duplex sets up that were factory fitted had a tensioner.

 

For what ever it's worth, I fit duplex to all my engine builds and on 90% of those, I also fit a tensioner.

[PACINO]

Yes Spider, I understand what you mean. In my case I am not going to put the tensioner on it.
* Now you can see better what MED told me in my message above, using the Forum's photo processor.