m3ben05 wrote:Any idea what causes them to be so noisy? Mine does quiet down when it gets warm but its still pretty loud!
AFAIK theres a few reasons.
i) Oil type. I know not what you run with but mine sounds a lot healthier after I've changed the oil (3K) Currently using Motul 300V 10W40 from Opie. When it ran GTX (also 10W40) it sounded worse. Alternatively Rags used to run 5/40 Mobil1 and swore by it.
2) Followers/Shims. As you know they run solid lifters which are better at high RPM than hydraulic equivilents. Though to be honest unless you are going above 7500-8 I daresay (guess!) that they arent needed really on a road car and as such are really for homologation purposes. Anyhow, try closing the shim clearences to their minimum and see if that helps.
3) Chain noise. Cam Chains are notoriously noisy in operation. Again, I cant say how many miles yours has done but you may find the guides are getting worn and the chains moving a little creating extra noise.
4) Exhaust Manifold. Lots of people can get caught out with a slight manifold leak, which can sound like the ticking sound of the valve gear. Of course as the manifold gets hotter cracks/leaks can either expand and seal or expand and leak. So its not always obvious.
But ultimately the S14 is a race derived engine and strangely I dont think quiet operation was very high on the list of specs BMW wanted
