Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Unwanted and undiagnosed engine noise

My 2017 car has developed a new noise which is a knocking which I think is coming from the engine. Not all the time and difficult to diagnose when it happens. Not particularly under load but just certain combinations of revs and load.
To me it feels as if it is engine as opposed to transmission.
The car is with a garage who have taken the tops off the engine and the front cover and looked at the cam belt etc. Nothing obvious and they are struggling to diagnose. Have also looked at transmission, drive and compensator
The next step is engine out and strip and this will then be time and money of course.

Are we missing something obvious? I have googled and searched but easy to miss something with a clumsy question. Does the hive mind have an answer?

Any help gratefully received. I can just see the good weather slipping away before we get it back.
Thanks

Checklist ideas:
1. Nothing loose in the camchest? This is now pretty reliable but wasnt in the past.
2. If Bleazeyed, does the Centa drive rock? It should be solid with the crankshaft. Mine had to be redone (after G&G in 2022!).

Nothing loose in the cam chest as far as we are aware
Not Bleazeyed (yet at least)
Thanks

look with a scope for chunks of rubber in the Centa bellhousing.

To be fair to the garage that was the first thing they suggested and looked for.
So many noises come from the car it is hard to understand from where they all emanate but I’m pretty sure this is engine.

Trying to locate any noise on these cars is near impossible. I actually made an attempt to track down a few of the rattles and knocks last week. The result being I now have twice as many as before and the car wouldn't start as I disturbed some of the wiring behind the dash. Good luck with your hunt and fingers crossed it's something totally innocuous.

What is the mileage of the car and what makes you suspect it is the engine rather than transmission (not saying it isn't just tying to understand more).

Is it a metallic knocking or more a buzzing vibration?

If you can still drive the car get it to the revs/speed where it's making the noise and without moving the throttle change down a gear. Does the noise change? Then accelerate and see if it comes back at the same road speed but with higher revs.

Are you in the UK and, if so, is it with a garage/dealer who understand the S&S?

Being old and tend to do things in an Old School manner, if I were looking at the engine I would take a flexible plastic/rubber tube and put one end to my ear and the other one various parts of the engine. Rocker Boxes, cylinders, crank case, cam chest and try to find the offending noise.

We are in the UK and the car has done about 5500 miles. A while since I have driven it now but it felt like the noise was coming from the front and just 'felt' as if it was engine rather than transmission. More revs than road speed for one thing.
Agreed that I need to drive again and put a very analytical view to it.
The garage is a Morgan dealer and service centre but I suspect that their technicians are more used to higher tech engines. I'm not knocking them. They had the balls to ring up and say that they don't know what it was and to discuss what we do next because it could start getting expensive. Hence my search for a common problem that may simplify matters.
However nothing obvious is surfacing. Not the first or last person to have an awkward noise that is difficult to diagnose I'm sure.

After all this I will probably find that it is a loose seat runner or something inane as per Karlosfandango's theory above.

When it stops making the noise you need to worry, because that means a bit has dropped off.

Tim