my 1985 635 csi engine is as noisy as a diesel, are my valves adjustable? the mechanic wasn't sure if it is.

they sure are, pretty easy job as well. here is a link to the process. Make sure you follow the directions for the M30 motor:

http://www.bmwe34.net/e34main/Maintenance/Engine/valve_adjust.htm

-Jeff

The valves are adjustable and your mechanic will not have any problems doing it. You could do it yourself if you want and we can give you a step by step.

they sure are, pretty easy job as well. here is a link to the process. Make sure you follow the directions for the M30 motor:

http://www.bmwe34.net/e34main/Maintenance/Engine/valve_adjust.htm

-Jeff

Thanks Jeff, that's very helpful. And BMW Performance, I would love to try it this weekend. Any pointers and tips would really help.

It's all about patience & taking your time.The feeler gauge should be snug, not too loose or too tight. Use 2 extra feeler gauges, one the next size down & the other next size up. The smaller should go in easily & the other not at all. I showed my son how to do it once and now he's nearly an expert. He didn't even know how to hold a feeler gauge before that.

Better get yourself a new mechanic who can offer you more competent advice on your car. Adjust the valves yourself, relatively simple procedure.

A couple of items also.
I would also do the Oil Spray Bar modification.

I did it and it really pumps up the oil spray pressure
on the valve train.

Get a new gasket for the valve cover also.

Remove the spark plugs to help the engine rotation
for each adjustment. I purchased a tool from Bav auto.
It is a spring loaded tool so you can't over tighten the
valve lash.

I'll add a few myself:
-don't drink or use mind altering drugs during this procedure
-don't overtighten or use the low clearance #. You'll find that your engine will run much better at the larger setting. I'm even a little big at .014 warm. Take your time and double check your results before firing it up. and then...enjoy!!

I'll add a few myself:
-don't drink or use mind altering drugs during this procedure
-don't overtighten or use the low clearance #. You'll find that your engine will run much better at the larger setting. I'm even a little big at .014 warm. Take your time and double check your results before firing it up. and then...enjoy!!

I am no scientist but could someone say why larger tappet clearance
would make this engine run smoother.

I have worked on a lot of engines and this just seems backwards to me.

Is the BMW factory clearance too tight in the first place?
I did my engine at factory specs and the idle is fair.

A lot of guys say to go larger but I have not heard why

-don't drink or use mind altering drugs during this procedure

Could that be the voice of experience we hear? :D

I also don't see how a larger clearance would be beneficial. I know that a smaller clearance* will give you slightly more power (effectively longer duration), and looser clearances make more noise.

* ~.008-.010, usually done only or mostly on the intake side, due to the risk of burning an exhaust valve if the clearance is too tight.

I have yet to find out why, except that when I bought the car it had a rough, lumpy, rich idle. After checking all sensors and tuning it the result was the same. I pulled the valve cover and found tha valves at .010 and the motor was very quiet, which I didn't like seeing it is a solid lift set up. The book said warm at .012, so I said what the hay, and set them at .014. INSTANT transformation. The idle settled, the exhaust cleared (getting total combustion) and power and economy improved immediately. Who knows, differences in feeler gauges? I doubt it. Valves settling in their seats , tightening the clearance over time? possible. I think it's either a typo error or poor translation or something. But I do know this. On a solid lift you must hear a little something from the valvetrain. Whether due to cold vs. warm expansion or just valve head seat time that's the way it is. btw, the longer that exhaust valve can sit on the seat the cooler the valve will be. Intake valves can be clearanced a wee bit tighter but why bother? I'd like to talk with some of the twin cam guys and see if they're doing anything with cam timing advancemnt and overlap and see if they run into any rough idle conditions.....But all in all, if you go .012 you won't hurt anything and neither at .014. It's just a matter if you're happy with it and it runs right. Mine at .014 runs cool and gives good power. Revving it up over 4k with no load on it in the driveway will make a little bit of racket, but it's hard to tell between the valves and the injectors.

Oh yeah, Layne, I don't want to hijack this thread but yeah, you're right. Over the wkend ask me about my $6K engine that I blew up in the garage due to a split second, micro momentary lapse of attention. Looking at in hindsight yrs later, it was truly glorious! All the proper noises and parts literally flying thru the air!

Better get yourself a new mechanic who can offer you more competent advice on your car. Adjust the valves yourself, relatively simple procedure.

this was exactly my 1st thought when I read the OP.