Citroen XM Forum

Irrespective of 'rough running' the speed of the flywheel cannot vary at the rapid rate of that belt flap.
It's a weighty flywheel, for heaven's sake, unable to 'tremble'!

Will ask again: what happens to the flapping when compressor or heavily-loaded alternator kick in?

White Exec wrote: Thu Jul 15, 2021 11:48 am ............

Will ask again: what happens to the flapping when compressor or heavily-loaded alternator kick in?

Not tried that yet..........the main cooling fans did come on, the flapping remained (not sure if the fans cause the load you are asking about)


Funny day so far
.....when injecting Dynax anti-corrosion cavity wax I always blow the airline into the cavity first......doing the left side engine chassis down leg....inserted the air pistol nozzle and this lot blew out

True grit!
Headlights beam + HRW + cabin blower should load it up.

OK

I watched, and listened to, your video again and couldn't really detect any rough running, just general mechanical noise and the belt flap.

Diesels do create vibration at idle due to having high compression slowing the crank on each compression stroke, followed by rapid acceleration on each firing stroke.

The "bag of spanners" noise at idle is due to the rapid rise in temperature in the combustion chamber, causing noise.
This stops under load conditions due to the air-fuel ratio moving away from extremely lean.
A diesel engine is un-throttled, so receives a full charge of cooling air every induction stroke, so the combustion gasses cool, then heat rapidly.

A petrol engine is throttled and at much lower compression, so runs smoother under no load, but is vastly less efficient, so produces far less torque, which I what gives rise to the vibration.

Any imperfection in fuel delivery volume, or spray pattern will exaggerate any issue.

It's probably not worth bothering about, but a dose of injector cleaner, with cetane improver, may make the injection smoother.

Paul, noted the Epic injection system appears to give the most power and noise, of the three systems fitted to these engines.
That would be correct, as it has a higher injection pressure (160Bar), so greater atomisation and more rapid delivery.

Knowing that I will not need to strip the engine down, I now have the car down on its own wheels and will pull it out of the garage over the weekend.....I need/it needs light.

I regard getting it out of the garage as a bit of a mile stone for me .... phew

VERY hot today, not the best day to spray rust proofing wax under a car. (other than it is the best time to apply it being hot and dry)..........but I am covered in it and STINK AGAIN !

Having done all that protection, you'll be able to drive around feeling decidedly smug, even if a bit waxy.

and very stinky...

It has not seen sunshine for quite some time....