> I'm hoping someone on the list can help me with an unusual noise my
> '89 325i makes starting at 2500 rpm.

From dale_at_unofficialbmw.com Tue May 7 19:46:35 1996
Subject: Re: <E-30> 325 Injector Noise

Hi
On my '89 325i with 125k, I used to have this noise, but tracked it to the valve train not the injectors. Use a long screwdriver held against your ear (bone to plastic handle for best results) to track down the noise.

Just thought I'd let you know what I did to solve this problem:

1. replaced rocker arms and rocker shafts result: noise went away until the arms seated to bad cam, then came back (I didn't notice the pitted cam when I had it apart)
2. replaced rocker arms and cam shaft result: noise went away for awhile (4k) then came back, not as bad
3. Valve clearance for this engine is (0.012" warm) (0.010" cold), I

   adjusted mine to (0.009" cold). I can't recomend you do this as it is not recomended by the factory, but it's worked so far for me. Made all the difference in the noise, but the idle is a little rougher.

Dale

From bmw-digest.v4.n364 Sun Mar 31 21:35:58 1996 From: Evan Arnerich <egabc_at_lightspeed.net> Date: Sun, 31 Mar 1996 07:48:52 -0800
Subject: Re: <E30><325is> "Clicky" valves

Karl Zemlinwrote:

>I once had a mechanic (at a local CCA Chapter "Tech Session") adjust my
>valves. Spec on my engine in .010" cold. He adjusted them with the engine
>warm, and set them with a little more grip on the feeler gauge than I
>usually use.
>
>My engine ran quieter after that tech session than ever before. FWIW, "a
>little more grip" would only account for a few tenths of a thousandth, so I
>don't really consider that part of the adjustment to be significant -
>adjusting with the engine warm was probably the bigger contributor to the
>quiet valve train.

>Any time a mechanic tells me that the factory specs are incorrect, that's a
>shot against them in my book. BMW cars are very well engineered. As an
>engineer, I am always impressed with the accuracy of the information in the
>documentation. The specifications for servicing your engine were developed
>over time by a team of trained, experienced, educated engineers. I don't
>think one mechanic's opinion is worth much compared to the time and effort
>that goes into documentation. If the book says 0.010" cold, that's what I
>do.

I agree that the cars are engineered well, but maintenance procedures are probably written somewhat for an "in the field" environment (i.e. time efficient adequate to protect the valves, but not necessarily for the ultimate performance). IMHO, Setting them warm has some advantages (but also IMHO more disadvantages).

Pro:
You are adjusting the valves at (close to) their designed operating temp, so a small amount of error doesn't magnify to a larger amount of error.

Con(s):

1. The operating temp varies depending on operating condition (e.g. street

   vs. track), so what engine temp do you want your valves set at?

2. It's hard to get consistency when engine is warm. The head starts

   heating, then cooling once you turn it off, so by the time you get the valve cover off, the temp had changed. With a cold engine, it's not changing temp _while_ you're working.

3. You might burn your hands. :-(

I think you'll agree that not everything from the factory is necessarily the best for every individual (person or car). Remember, everything is a compromise - even a full race car. If everything were perfect, there would be a lot fewer tuners, aftermarket vendors, and digests like this. We're all around to make the best (in our humble opinions) a little better.

BTW, I do mine cold (and I _always_ hear a little bit of clicking). Just my 1/50th of a buck.

Evan
'87 325