1-17-16: Solved - RMW suggested checking my rockers and that was the source of the noise. So happy it wasn't the supercharger!


Cars been running pretty good. About 1000 miles since new injectors, cam and tune. Engine has a 15% pulley, CAI, and colder plugs. This past week I noticed some unhappy noise above 3000 rpm. Hard to describe, probably a knock or rattle. I do use 93 octane fuel.

2003 R53 with about 150k miles. Did some engine work last year.

I have checked oil level (its at the top mark). Its a dealer oil filter with cage inside. The oil pump, timing chain, chain tensioner and belt tensioner were all replaced in the last year (I've been going through the engine) and seem good.

Please listen to the video and post any ideas. The noise I was worried about starts at about 14-15 seconds once my excellent helper revs the engine up. If you watch the whole thing, it goes away once the rpm's drop below 3000.

I tried localizing it with a mechanics stethoscope and the only place that was noticeably louder was the supercharger horn.

 

I personally have not encountered that sound before. However, if the supercharger has not been rebuilt/replaced and/or the waterpump is the original those would be the first things I would pull off and examine. Best of luck, let us know how it turns out

 

Was it the hydraulic lash adjusters? Also, when you say "new cam," was it a stock OEM cam or aftermarket? If aftermarket, which one?

What did you do to fix it (if you have)?

 

To rule out any components in the belt drive detension the belt while the car is running and see if the noise goes away. If so, then start diagnostic on the belt drive components, if not, that sounds almost like chain slack or a broken timing guide rail.

 

I had put in a new RMW street cam just before I had it tuned (about 1100 miles ago).

It is fixed - I switched out all the rocker arms (w/ hydraulic lash adjusters) for a set I had from another head I was saving for modification.

Noise went away.

Would love to know how to test / inspect the individual lash adjusters. All the plastic retaining clips were in place on the rockers - that seemed like the obvious problem, but it wasn't that.