23 replies to this topic

[roly666]

Hi all, just put my 1380 back in the min, connected it up last night, when I fired it up it ran really nicely and sounded smooth and revved responsively.

However. After a minute or two of running it seemed to develop a whirring noise from the timing chain end of the engine.

I took off the fan belt and ran it briefly to rule out the water pump and alternator.

Really hoping I wont need to strip out the timing chain in situe!

Im running duplex with a tensioner

Any thoughts greatly received!
Cheers.

[Gremlin]

Did you put a new chain in, and how old are the sprockets?

[Stevie W]

Hi,

With the duplex timing chain set-up, there are some mods that need carrying out on the cover.

There's a little notch near the bottom of the cover that needs hammering out and depending on which cover you have, there's a ring around the hole which is connected to the breather oil separator that needs grinding/ removing to give a running clearance.

Having said all that, I would've thought you'd have heard the noise on the initial start-up!!

Something to check anyhow!!

Cheers, Steve.

[roly666]

Hiya, thanks for your quick replys. Its not a new setup at all. Already done around a thousand miles with it.
Took the engine out to replace all gaskets and bolts in the gearbox/diff due to some highly irritating oil leaks!

[Stevie W]

Ok,

It could be the tensioner pad breaking up......but I emphasise could be!

There are 2 separate schools of thought on whether a tensioner should be used with the duplex set-up, but if fitted and tensioned correctly, the tensioner should cause no problems.

I know it's not what you want to hear....but whipping out the rad and removing the timing chain cover to check if all is ok would be worth doing.....just in case.

Before doing this though, have a good look around the rad cowling and double check the fan blades aren't touching anywhere. They also run very close to the oil separator canister on the timing chain cover so, again, make sure they're not touching here either!

Cheers, Steve.

[roly666]

Thanks Steve.
Will whip it out tomorrow.
Pretty positive its not the fan fouling as I ran it for a couple minutes with no fan belt amd still had the noise.
Will report back tomorrow.

[Stevie W]

Ah right, sorry you did state that it was still there with the fan belt off!!

Hope you get on ok tomorrow.

Cheers, Steve.

[roly666]

I haven't been out to the min yet, but was thinking last night, would it be a bit whirry if I had overtightened the tensioner pad?
Just a thought!

Gutted I'm gonna have to drain all that lovely new oil out! :-(

[roly666]

Scratch my last comment! Iam a fool!

[roly666]

Ok guys.
Got it stripped down, looks all ok!? A bit of wear in the tensioner but all in all it looks alright!

Big question is do I put the tensioner back on? Read a few threads on here arguing that it is not needed............
Any thoughts?

[Stevie W]

Hi again,

Glad you found nothing amiss!

The duplex chain stretches much less than the simplex, so it's not absolutely necessary to have one fitted.....the choice is yours!!!

Most people time their cams in a couple of degrees advanced to what the cam manufacturer recommends to allow for a little chain stretch, which once happened will leave the cam timing pretty much spot on!
The tensioner largely takes out this chain stretch....

Cheers, Steve.

[roly666]

But this does still beg the qurstion.....what was causing the noise in the first place!

Grrrrrrr! Bloomin thing!

MOT Monday, riv run Friday! Only popped the engine out to sort out oil leaks! Was running perfectly before!

[Stevie W]

Could you possibly post up a video of the noise?

Cheers, Steve

[tiger99]

The tensioner DOES NOT run correctly against the duplex chain, and so is NOT used. To my knowledge, there has never been any debate about that until recently. The advice that used to be given as part of the duplex conversion was simply "adjusting" the cover, countersinking two screws, and throwing away the tensioner. It seems to be quite recently that keeping the tensioner has become fashionable, and that is because what was once common knowledge is becoming lost. We can do better on this forum, by nipping that in the bud, I hope.

 

That does not mean that you can't use a tensioner on a duplex chain, but it would have to be wider, to run correctly, and you can't get such things, as far as I can see.

 

But that may or may not have any connection to the whirring sound. At least there is only minimal dismantling needed to remove it to see what happens.

[roly666]

Tiger - you will be pleased to hear I am now tensioner free and will instruct my friends to do the same!

Stevie - I'm afraid I can't post a vid of it, as the noise seems to have vanished along with my tensioner!

Thanks guys for all your help!

If you are heading to Newquay next weekend, I would like to buy you a 🍺 !