Did you check the alignment of the tensioner sprocket with the chain ? The carrier can twist and this possibly happened when the chain was broken in the initial incident
regards
Rohan
Alignment looks ok but i’ve ordered a new quadrant, i don’t know what else to try
John
I have not read all of the thread so dont know how far the engine was disassembled but did you replace the oil slinger (front of crankshaft?) If you did was it fitted the correct way round?
If you bought a new slinger did you get the correct one as the Lotus type is slightly different to the Ford Cross-flow type having a recess so the chain does not rub on it.
Yes I replaced the original one
John
With the correct one?
Here is a picture showing the difference in slingers, the two on the left are Cross-flow types and shows where the chain was catching when used in a T.C.
The one on the right shows a Lotus type and shows the “relief” in the slinger.
I think the timing chain can rattle against the casting surrounding the water pump, but I think this only happens if the chain is too long, i.e has stretched or the chain tensioner is extremely slack.
The tensioner should be tight enough that you can feel the chain tighten at the top between the two cams, and you tighten it untill you can flex the chain up and dwon about three quaterers of an inch with your fingers roughly half way between the two sprocket wheels.
It must have happenned at some stage on mine, because there are two grooves in the waterpump casting, inside the timing case.
See my long topic about conducting a Clay Test for details about putting the Twin Cam head back onto the block.
[viewtopic.php?f=39&t=26441&hilit=valve+clearance](https://lotuselan.net/forums/viewtopic.php?f=39&t=26441&hilit=valve+clearance)The chain clearance on the Burton cartridge waterpump casting can be tight and some people have reported needed to do some fettling in the area close to the tensioner
cheers
Rohan
I have a new brass tensioner but it will need some reaming out for the new pin to fit. What sort of clearance should I have? The old one is a easy fit, perhaps that is where the noise is coming from.
Thanks John
Hi
I fitted a new quadrant some years ago it did not require reaming!. It is able to move horizontally on the pin in use.
Did you locktight the sprocket bolt.
Give it a good check when fit the new quadrant, make sure the chain is tensioned correctly before you hand turn it then on the battery plugs out. Cam cover off.
John
Fitted the new brass carrier after havng to ream out to fit the new pin, the carrier now sits equidistant on the pin with the chain in perfect alignment
As soon as I attempted to rotate the engine the clanking noise is still there, I just cannot fathom why it would turn quietly the other day.
John
You might have screw loose, in the head maybe?
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? Front engine pulley loose, do you have the fan belt fitted ie are there any ancillaries rotating.
I have been advised that the QED front covers often have clearance problems with the chain rotating…
Another stripdown!
John
Buy or borrow a cheap borescope and investigate down the cover where the chain may be hitting before pulling it all apart again
cheers
Rohan
A Mechanics Stethoscope can also be handy for locating a source of noise. They’re just a few quid on Ebay.
While I agree a stethoscope would be handy you have only to turn the crank a fraction to get the noise, the chain must be touching somewhere around the bottom of the casing. It’s a very echoey sound.
John
A bit of a long shot but can the dipstick tube (and/or dipstick) foul the chain if the tube has been pressed in too far?
Yes if the dip stick is bent or the tube at the wrong angle it can hit the chain, been there done that have and have grove on the dipstick to prove it.
In my case the dip stick was bent by the hole in the windage tray being a little to small
Try twisting the dip stick 180 degrees or removing it to see if the noise goes away 
cheers
Rohan
Good call Rohan. There is of course the possibility that something has been unwittingly dropped down the front of the engine during assembly John? I wish I was nearer…
At last the noise has been sorted, it was a chipped tooth on the crankshaft sproket.
Just don’t mention woodruf keys, replacing or the cost!
John