Flywheel rattle?
Discussion
We're building an E21 BMW and have fitted a low mileage M52/2.8 engine, on Jenvey ITB's, six branch and running DTA Pro 90.
We have fitted a lightened billet steel flywheel, that are dynamically balanced to 20000rpm, but there is a noticeable resonating noise / rattle on overrun. The gearbox is known to be in good order and the clutch is a new, uprated item from AP.
I've been told that a certain amount of chatter, from using a significantly lighter flywheel, is quite common? I've no experience of this myself though, hence my question. Has anyone else had similar issues when fitting a lightened flywheel, or can explain potential reasons for the resonance?
Thanks in advance.
We have fitted a lightened billet steel flywheel, that are dynamically balanced to 20000rpm, but there is a noticeable resonating noise / rattle on overrun. The gearbox is known to be in good order and the clutch is a new, uprated item from AP.
I've been told that a certain amount of chatter, from using a significantly lighter flywheel, is quite common? I've no experience of this myself though, hence my question. Has anyone else had similar issues when fitting a lightened flywheel, or can explain potential reasons for the resonance?
Thanks in advance.
It's probably not the flywheel but the first motion shaft in the gearbox which is now rattling about a little now that there isn't a big heavy flywheel smoothing out the peaks and troughs of the combustion cycles. If it is this, it'll do no harm. The chances are this is your answer if the rattle goes with the clutch depressed.
Whilst i appreciate this is on diesel engines in Land Rovers with the LT77 or R380 gearboxes the following might be of interest:
"My gearbox rattles on idle, in neutral, with the clutch up
This is very common on Diesel engined vehicles. The clutch friction plate has a ring of springs, which are there to soften the knock of the diesel engine to stop it being transmitted to the driveline. Often especially with a new clutch these springs are quite tight and a lot of the engine knock goes through to the gearbox and makes the gears "chatter" together when the box is in neutral and the clutch up, it goes when the clutch is depressed. This can sound quite bad and does vary from car to car but is not detrimental to the life of the gearbox and we view it as an undesirable characteristic of the LT 77 and R 380 as opposed to a fault with either the gearbox or the clutch."
http://www.ashcroft-transmissions.co.uk/frequently...
"My gearbox rattles on idle, in neutral, with the clutch up
This is very common on Diesel engined vehicles. The clutch friction plate has a ring of springs, which are there to soften the knock of the diesel engine to stop it being transmitted to the driveline. Often especially with a new clutch these springs are quite tight and a lot of the engine knock goes through to the gearbox and makes the gears "chatter" together when the box is in neutral and the clutch up, it goes when the clutch is depressed. This can sound quite bad and does vary from car to car but is not detrimental to the life of the gearbox and we view it as an undesirable characteristic of the LT 77 and R 380 as opposed to a fault with either the gearbox or the clutch."
http://www.ashcroft-transmissions.co.uk/frequently...
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