Duplex chain tension.

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midget
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Duplex chain tension.

Post by midget »

Currently fitting Duplex chain to an A+ and am concerned about the tension I have when fitted. It is incredibly tight and would like advice from the many who have fitted these? It was very difficult to assemble, and in my opinion way too tight. I do have the tensioner as standard but not fitted yet.
John
philthehill
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Re: Duplex chain tension.

Post by philthehill »

There should be very little flex in the duplex chain when fitted but it should not be so tight so as to to give concern.
The 'A' Series duplex timing chains should all be the same but the reality is that some timing chains are tighter than others but should still fit without being overtight.
Fitting the duplex chain set to the 'A' Series should be reasonable easy task.
Have the crankshaft and camshaft pulleys been aligned by adding or removing the shims which are located behind the crankshaft sprocket. If they have not been aligned the tension on the chain can increase to an unacceptable level.

As regards the tensioner, the chain should be at a sufficient tightness before the tensioner is fitted, the tensioner is there to take up the slack after several thousand miles.
timing chain tensioner.jpg
timing chain tensioner.jpg (1.17 MiB) Viewed 1229 times

midget
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Re: Duplex chain tension.

Post by midget »

Thanks Phil, the sprockets are in alignment, so just may have a tight chain? I will bear this in mind when first running.
John
Nickol
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Re: Duplex chain tension.

Post by Nickol »

I come back to this thread after I remembered the picture Phil posted with the engine fixed to an engine stand.
In preparation to remove the Crankshaft for regrinding I purchased said engine stand but then realised I cannot fix it to the backplate of the engine as this must be reoved to take out the Crankshaft. Then I saw the picture showing the engine fixed somehow to the side of the block.

This is really a question for Phil ( again.....) whether you could say how you attached the block to the stand? I should add that the motor is not from a Minor but a triumph herald.
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philthehill
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Re: Duplex chain tension.

Post by philthehill »

You just have to play around with the engine to stand 'Z' mounts which may have to be reversed or having additional holes drilled in the engine to stand 'Z' mounts or in the mount plate itself.
I have had to do both to utilize the engine stand with different engines. You do have the ability to modify or rearrange the 'Z' mounts on the engine stand. The engine stand does not have to remain as bought.
Here is a link to a 'U' Tube video which shows a Triumph engine mounted on an engine stand with access to remove and fit the crankshaft. You do need to use all four 'Z' mounts otherwise the engine block may distort or break.
https://www.youtube.com/watch?v=9ZTXfkJAR_o

Nickol
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Re: Duplex chain tension.

Post by Nickol »

thankyou for that. I was trying to avoid the end fixing as it gets in the way when installing and setting up the end plate. Will persevere.
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Murrayminor
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Re: Duplex chain tension.

Post by Murrayminor »

On the subject of mounting an A series engine on a stand, I came across this video which seem to have a special plate bolted to the engine block:

https://www.youtube.com/watch?v=rad7cdJmT6k

I did a little bit of research and came across another adaptor plate that was bolted to the alternator mounting points and also the oil filter housing mounts.
I don't know how strong those points would be, there was an actual plate made to suit these holes, which in turn was welded to the main tube on the engine stand.
It seemed to work but as I said I don't know how strong the mounts would be.

I have found the link here:

https://jbfab.co.uk/product/mini-a-aplu ... d-adapter/

Dermot.
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pgp001
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Re: Duplex chain tension.

Post by pgp001 »

Dermot

I have just been using one of those plates on my engine stand, they actually work very well indeed.
I had to make up a few spacers, but otherwise it bolts straight on and the engine will rotate easily.

Phil
philthehill
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Re: Duplex chain tension.

Post by philthehill »

With the Marina/Ital block (which does not have the oil filter arrangement as per the 1275cc Midget/Sprite) the N/S engine mount bolt holes are used with the engine stand as per photo below. You just have to juggle the 'Z' mounts to suit - see arrangements of 'Z' mounts in photo below.
Timing the cam 1.jpg
Timing the cam 1.jpg (370.07 KiB) Viewed 1041 times

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