Grind/rattle at exactly 3k RPM...

[hrstudioplus]

I've been experiencing an odd grind or rattle that appears only when my tack reaches 3000 RPM... It sounds very light, not a deep grind at all. But it's there nonetheless. Only in 1st and second gear. After 3rd it's not apparent.

Anybody else experience this before? I'm running a 1972 with stock Solex carb, stock air filter, and pretty much stock everything except water pump and alternator.

It's really odd, and I can't determine if it's a grind or a rattle either!

Arrgghh.

-Hassan

[InkaSteve]

If it still has the original metal heatshield over the exhaust manifold. They get brittle and start to split at the mounting bolts and rattle at certain RPMs. If so, replace with a combo gasket/heatshield from the 320i, or just drip a little JB weld on the crack. (it will hold for a while, but need to be redone occasionally) Hope that is it, because it is the rattle that is the cheapest and easiest to fix. I am sure others will share other possible causes of the grind/rattle.

good luck

[Dutchie3719]

check the exhaust bushing on the exhaust-transmission mount. The rubber on mine had died, and i got a rattle at anywhere between 2500- 3000 rpm

http://realoem.com/bmw/showparts.do?model=2213&mospid=47140&btnr=18_0333&hg=18&fg=05

part number 01

[TobyB]

yeah, along the same lines, look at the entire tailpipe-

especially where it goes over the subframe-

you're looking for shiny spots...

t

[auggiemize]

Mine is at 3100...I thought it sounded llike drive-shaft, guibo, u-joint something from inside the car...from the outside, however Dr. Pugh determined it is the (Ireland) exhaust on the rear sub frame...His diagnosis was BFH... Dave V. in NC