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constant thruth bearing rattle

Posted: Sun Jul 06, 2014 12:48 pm
by slim91
hi all i have recently put and m52 in the e30 with a 318is gear box with lightweight m20 flywheel and new sach clutch im using a 325i release bearing first one bought from euros and lasted about a week bought one from bmw at the price of 70 quid and the f***er rattled from the second i started it :( am i using the wrong trush bearing?

Re: constant thruth bearing rattle

Posted: Sun Jul 06, 2014 12:56 pm
by ross_jsy
Sure it is the release bearing and not a rattly Getrag? A lightened flywheel will magnify this problem

Re: constant thruth bearing rattle

Posted: Sun Jul 06, 2014 1:00 pm
by jmc330i
Does the noise disappear when you depress the clutch pedal? It may not be the release bearing, but the lay shaft bearings in the gearbox.

The E30 325i bearing should work, although as I've found does result in a high biting point.

Re: constant thruth bearing rattle

Posted: Sun Jul 06, 2014 3:34 pm
by slim91
The gearbox is mint it's only had this problem since I bolted the m52 in and yes when I press the clutch the noise goes away. That's the other thing I don't have a high bite point it's quite low cheers

Re: constant thruth bearing rattle

Posted: Sun Jul 06, 2014 3:49 pm
by ross_jsy
How do you know it's mint? Have you rebuilt it? If not, then it's a 20+ year old gearbox. Getrag's tend to rattle.

Just for your information, I have 2 Getrag boxes (both "sport" boxes) and both their layshafts rattle and both stop rattling when you depress the clutch. One is so bad I thought it was the bottom end going before I pushed in the clutch, the other is ok but every now and then has a rattle

Re: constant thruth bearing rattle

Posted: Sun Jul 06, 2014 4:32 pm
by maxfield
My dad had a brand new gearbox on his M3 from BMW, the lay shaft rattled on that.

Very very common.

Re: constant thruth bearing rattle

Posted: Mon Jul 07, 2014 1:12 am
by HairyScreech
The lay shaft rattle problem was/is common enough that they took to putting orings in the transmission to help dampen the oscillations in the layshaft.

Even brand new boxes were doing it so I have been told.