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Duplex Timing Chain Kit

Posted: Wed Oct 07, 2020 1:34 pm
by MorrisJohn
I’m just wondering how long it should take a competent garage to fit a duplex timing chain kit to my Moggy?

Re: Duplex Timing Chain Kit

Posted: Wed Oct 07, 2020 3:08 pm
by philthehill
No longer than 1 working day.

It is an easy job for the home mechanic.
Plenty of help on here if you need it.

Re: Duplex Timing Chain Kit

Posted: Wed Oct 07, 2020 4:07 pm
by MorrisJohn
philthehill wrote: Wed Oct 07, 2020 3:08 pm No longer than 1 working day.

It is an easy job for the home mechanic.
Plenty of help on here if you need it.
Thanks Phil. I’ll give it some thought.

Re: Duplex Timing Chain Kit

Posted: Wed Oct 07, 2020 5:04 pm
by Nickol
philthehill wrote: Wed Oct 07, 2020 3:08 pm No longer than 1 working day.

It is an easy job for the home mechanic.
Plenty of help on here if you need it.
As long as you have the right Tools..... 😁

Re: Duplex Timing Chain Kit

Posted: Thu Oct 08, 2020 9:40 am
by SteveClem
Reading some old posts, I see that the legendary bcc ecosse recommended using a simplex kit with tensioner to reduce noise rather than switching to duplex.

Re: Duplex Timing Chain Kit

Posted: Thu Oct 08, 2020 9:47 am
by liammonty
SteveClem wrote: Thu Oct 08, 2020 9:40 am Reading some old posts, I see that the legendary bcc ecosse recommended using a simplex kit with tensioner to reduce noise rather than switching to duplex.
I think that the benefit of the simplex, as you say, is that it can be fitted with a tensioner. The downside is that is wears faster (and the tensioner wears too). The duplex may be slightly noisier, but is much more durable.

However, I think that if I only had suspected noise from the tensioner, I would be whipping the timing chain cover off and inspecting it before rushing to fit a new chain, particularly given the history of the engine (i.e. recently rebuilt). I'd want to make sure that the noise in question is actually due to the timing chain.

Re: Duplex Timing Chain Kit

Posted: Thu Oct 08, 2020 10:16 am
by philthehill
Fit the duplex with the tensioner.
Then you have the best of both worlds.

If the tensioner is fitted correctly there will be very little wear to the tensioner pad.
The tensioner only needs to press lightly on the chain. In most cases that means the tensioner retaining bolt is mid position in the tensioner pad mounting bracket adjustment slot.
There is no loading on the timing chain on the return of the chain. All the loading is on the drive side of the chain as the crankshaft rotates the camshaft. The tensioner is only there to take out any return slack.
Whilst some do not remove the front engine plate to drill out the hole for the head of the tensioner pad retaining pin and improvise a retaining mechanism - I always recommend that the front engine plate is removed and drilled factory style and an original pin is used as per the factory fitment. Any other way of retaining the tensioner pad retaining pin has the possibility of the pin becoming detached and causing problems.
A Plus tensioner 1.JPG
A Plus tensioner 1.JPG (1.86 MiB) Viewed 976 times

Re: Duplex Timing Chain Kit

Posted: Thu Oct 08, 2020 12:35 pm
by myoldjalopy
If you fit a new chain, is it advisable to fit a new tensioner as well?

Re: Duplex Timing Chain Kit

Posted: Thu Oct 08, 2020 12:39 pm
by MorrisJohn
Thanks guys. I’m going to get a third pair of ears on it (a local club member) before I start delving into the engine as costs could rapidly spiral out of control...my gut feeling is that the engine is likely healthy due to the rebuild and being well maintained by the last owner.

If it weren’t for COVID-19 then a club meet would have been ideal for getting some experienced Moggy owners to hear it for themselves. It’s so hard to accurately describe.