Valve adjustment question

[Stir Fry A Lot]

I'm going for hp and not idle smoothness. What spec should I adjust them to? I'll be doing them cold.

[moroza]

Adjust them to spec. You won't get more power out of a different spec valve adjustment. In theory, if you adjust them to less lash, you'll get negligibly more lift and negligibly better airflow. In practice, the risk of the valve not sealing properly more than offsets the potential for minute gain.

Now, adjusting the cam sprocket to mess with the static valve timing might actually gain you something measurable (>1hp somewhere in the curve). Then again, since the M30 only has one cam, maybe not. Someone else chime in here.

You'll gain more power running slightly thinner oil than fiddling with valve adjustment. Hell, I bet you'd make more power just eating a lot of beans and standing in front of the air intake.

[Stir Fry A Lot]

So .010 is fine correct?

[moroza]

I don't work with slugs, drams, and furlongs. 0.30mm cold, 0.35mm hot. If you've never done it before and could use help, call me & come over.

[535ipower]

.012 cold for the m30 thats what i adjust mine to according to Bentley and other sources.

[Electricalbox]

So .010 is fine correct?
Sounds correct, be sure to get if you don't have them angeled feeler gauges. The way the head is shaped made me mess up measurements with a striaght feeler gauge. Best 5 dollars I ever spent... :)

[Stir Fry A Lot]

Cool, I'll probably do .012 then. This is my first M30 but have done adjustments on my 3 previous e30s plenty of times. Thanks all.

[acs325i]

make sure you take the adjustment at the top of the valve and not at the cam

[pldlnr]

A cold .012 is spec. It is the way to go. To do this, let the car sit overnight before you adjust. Make sure the lobe on the cam of the valve you are adjusting is pointed straight down at the top of the cylinder/piston when you go to adjust.

[E34Kevin]

There should be a DIY thread for a valve adjustment, I spent over 120 to get it done but seems like an easy job

[TGreene]

Yeah, it is something I need to do, but have no experience with anything like it so it kind of makes me anxious, like I might lose the car for a few days if I can't do it right the first time.

[Stir Fry A Lot]

Yeah, it is something I need to do, but have no experience with anything like it so it kind of makes me anxious, like I might lose the car for a few days if I can't do it right the first time.


Even a caveman can do it. Once you take off the valve cover it will make sense. Like electrical said make sure you have an angled feeler gauge, and like acs mentioned you don't put the feeler between the cam. You see a 10mm bolt that loosens the eccentric. You'll also see a hole in it that makes it possible to move it up and down. Just loosen the bolt and slide the feeler above the spring. Put a small allen or coat hanger into the hole to push it down on to the feeler, you want it to have a small amount of drag. Hold the allen in place while you tighten the bolt back up. You want the cam pointing down and the rocker to be sitting on the flattest spot of the cam. There are many ways to turn the cam, the method I use is getting two long pieces of wire such as an extension cord I strip about 1" off both ends and plug one end of it into pin holes #11 and 14 on the diagnostic port. If you touch the remaining two together the cam will turn. Make sure it rotates a few times if it doesn't fall into the right place. Don't try to bump it little by little. It sounds daunting now but it really is quite easy. I went with a .012 feeler gauge, if you cant find an angled one just buy a straight one and bend it up about a 1" from the tip. Sorry about dropping the ball on the write up but there are many DIY walkthroughs floating around.

You won't be out of commission for more than two hours your first time. Don't worry about it. Just make sure you have a deep 10mm socket because the valve cover nuts have little heads on them. Also make sure you have a new vc gasket and when you put the cover back on start from the middle and go in an X pattern. Don't over torque the nuts either because the cover may warp.