Layshaft noise

[Paul Holywood]

My R500 has a rattle on tick over from layshaft it seems, depress the clutch and noise has gone, is this common and should I get it seen to or just accept it?

If it's something that requires repair how much should I expect to pay to have the sorted?

[Paul Holywood]

IBDAET said:

THe noise is actually the clutch release bearing, not the gearbox. As Mark says this is common, and not really an issue. It will get really noisy before it fails, then I'd replace the whole clutch.

That's a relief I was under the impression its the gearbox ,thanks for your help.

[Paul Holywood]

Eccles52 said:

My Sigma 150 has the same thing, it's been like it from new (2007) and has done 15K without getting any worse so I would think it's fine although mine is a much lesser machine

Admittedly it's still bloody annoying and I'd like to fix it

Interestingly , does yours sound like the engine is knocking until you depress the clutch ? Or have you a different noise.

[Paul Holywood]

Mine does go when you depress the clutch, but sounds "clackity clack" .
lol it's very hard to discribed what I can hear.

[Paul Holywood]

Apologies, I didn't know what the abbreviation (tadts) meant, and when I see it a second time had to use google.
Thanks, so it's down to lightened flywheel and clutch?
Forgive me for my stupidity but I can't see the connection.

[Paul Holywood]

IBDAET said:

Flyuwhjeel has nothing to do with it. It is 90% CRB, or if the car has had its neck wrung and uses a sprung clutch pressue plate it can be the springs in the clutch plate rattling where they have becoime loose.

On an R500K there is no organic plate that is really capable of handling the required torque capacity, so there is a slim chance its the plate.

Thanks, if what you say is correct and I decide at some point to replace the clutch ,given the high torque, is there a more substantial kit I should go for, or should I keep oem.

[Paul Holywood]

IBDAET said:

Flyuwhjeel has nothing to do with it. It is 90% CRB, or if the car has had its neck wrung and uses a sprung clutch pressue plate it can be the springs in the clutch plate rattling where they have becoime loose.

On an R500K there is no organic plate that is really capable of handling the required torque capacity, so there is a slim chance its the plate.

Thanks, if what you say is correct and I decide at some point to replace the clutch ,given the high torque, is there a more substantial kit I should go for, or should I keep oem.

[Paul Holywood]

Advice taken,thanks.

[Paul Holywood]

MoPho said:

When I searched about this some years ago this is what I found: "The first motion shaft and laygear are dancing around a bit due to the fact that they are effectively idling with alternating accelerative and deccelerative cycles in time with the engine"
Apparently Caterham has varied the tolerances over the years and some boxes do it and others don't

I was under the impression it was this , I presume when depressing the clutch the shaft becomes motionless, thus no noise.

[Paul Holywood]

one eyed mick said:

It happens to many boxes in many cars and can be real pain in the -r-e it is caused by uneven /inconsistent idle speed ,highly tuned engine suffer the most and some just cannot be cured even by rebuilding the box and clutch surely a car like an r400/500 spends little time idling so there are only 4 courses to take 1 don't let it idle 2 depess clutch while its idling 3 switch the bl--dy thing off!! 4 Ignore it !!

Interestingly I'm looking at a previous poster who mentioned lightened flywheel, that would then indeed contribute to this noise, am I right in saying a heavier flywheel would make for smoother idle speed? But obviously have detrimental affect on engine response etc..
Hence why the lesser tuned engines may not suffer the same .

Note, this thread makes for good learning.

Edited by Paul Holywood on Sunday 21st December 12:07