adjusting valves

[Beach Bum]

When I unplug the AFM on my car it won't run at all. Odd.

The alternative is to just plug the PCV hose if you were to take the valve cover off.

Also, when I've got the cover off on mine, oil goes EVERYWHERE.

I just don't see how you can accurately turn the eccentric and tighten it down at the same time. Unless you're talking about just checking the lash with the engine on and making adjustments while off.

[StereoInstaller1]

more info on this please

I jacked up one side of the car and put it in 5th, and turned the back wheel(made it a 2person job)

That is such a pain in the butt.

If you jumper between 2 pins on the diagnostic port, the starter runs.

I do not recall which pins, so I check every time. Do a quick google of "unofficial BMW diagnostic port" and find that writeup.

[CorvallisBMW]

The AFM needs to be unplugged because the engine normally runs in a vacuum. With the valve cover off it's no longer in vacuum, which throws the AFM out of whack and makes the car start 'hunting', revving from 500rpm to 1500 and back again, constantly bouncing. Unplugging the AFM sets the engine in to a closed-loop mode and keeps the idle steady.

You can still do this on many older OHV V8s from the 60s, before emissions controls forced them to run the crankcase in vacuum. Most old domestic guys adjust their valve lash with the valve cover off and engine running b/c it's the most accurate.

[nando]

well the car idles at ~650rpm

cam rotates at 1/2 crank speed

60 seconds in a minute

6 cylinders on the engine

650/2/6 = ~55 openings a minute (a bit more than 1 second)

I dunno, it's tight but he says he did it.. you'd have more time at a lower idle speed (maybe that's why he unplugs the AFM?).

[Beach Bum]

Who says you can't?

I have done mine like that before. Unplug AFM, remove valve cover, start motor and adjust valves. Works fine. Kind of dicey (don't get your shirt cuff caught in the cam...) but completely doable.

I don't know if you're being sarcastic or what, but there's no way I can think of to adjust the valves with the car running.

[nando]

Who says you can't?

I have done mine like that before. Unplug AFM, remove valve cover, start motor and adjust valves. Works fine. Kind of dicey (don't get your shirt cuff caught in the cam...) but completely doable.

I thought I remembered you said you did it that way.

Unfortunately I can't even attempt it since my coils are mounted on the VC.

[otto325e]

I keep mine to spec at .25mm with the engine cold. I am deathly afraid of burning valves

[CorvallisBMW]

Even better would be adjusting them with a running engine, if it were possible.

Who says you can't?

I have done mine like that before. Unplug AFM, remove valve cover, start motor and adjust valves. Works fine. Kind of dicey (don't get your shirt cuff caught in the cam...) but completely doable.

[bzboardz]

very interesting thread, lots of good info

Now if we can get all you fools to use a pushbutton switch on the damn diagnostic port to bump the starter over instead of bumping it while pushing the car back and forth...

more info on this please

I jacked up one side of the car and put it in 5th, and turned the back wheel(made it a 2person job)

[whodwho]

OP the spring adjuster works well you can also use a go-no go type gauge until you get the 'feel' of it.

As far as the hot/cold adjustment, they should net you close to the same result and I highly recommend cold If you have not adjusted valves before.

As for the hot/cold debate, I suggest doing an initial adjust stone cold especially if it has not been done in a while or your first adjustment on it to get it set to your feel and doing a recheck at running temp hot and adjust the couple that maybe off and then installing your new VC gasket.

An old shop trick - you can take the VC off and use a large house fan set on top of the head and take it down to cold in about 20 mins.

[StereoInstaller1]

This thread has got to have some of the silliest shit about valve adjusting I have ever seen.

All the books say "stone cold", but they aren't talking about 20 degrees F, either. Somewhere around 75 F would make sense, ambient temps of a nice day.

Much warmer than that and the engine will cool while adjusting, making the whole job inaccurate.

The point of "lashing" the valves is to allow for heat expansion. If you could maintain a nice consistent temperature you could adjust for whatever spec you wanted, as long as you recognize that the engines temp needs to stay consistent. Good luck keeping the motor at 160, right? Keep the motor right around 75 degrees F, as you can do that temp pretty much all year.

Tightness again is just like the temp: consistency is the key. If you wanna sprain your wrist shoving a feeler gauge in there, go right ahead...but do it 12 times. I say a "moderate" drag is adequate, but only after you wipe away the oil film between the rocker tip and the stem.

Now if we can get all you fools to use a pushbutton switch on the damn diagnostic port to bump the starter over instead of bumping it while pushing the car back and forth...

[nando]

With all the engines I have built, both fuel injected and carbureted and small engines like quads and dirtbikes. I have found it best to do it when the engine is at normal operating temperature. In fact for most engines the specs they give you for proper valve lash is actually set at normal operating temperature. It takes an engine on average between 2 to 4 hours to completely cool down. That is more than adequate time to adjust valve lash. If you cannot do it in that amount of time you probably shouldn't be even attempting to do that.

agreed

most people are just too scared to try it. I do tend to wear leather gloves though, because it stays quite hot for a while.

FIY: the valve gap actually gets bigger as the engine warms up. I've always ended up with a much quieter engine adjusting them hot. Even better would be adjusting them with a running engine, if it were possible.

If you don't want to do it hot - fine - but stop telling everyone that doing it hot is "wrong", when there's a BMW spec for it. Doing it cold is the easy way, not neccesarily the best way.

also, either way you do it, it's possible to put too much pressure on the eccentric, and slightly open the valve. so what happens is the valve stays partway open when the engine is cold, and it runs like ass. the spring loaded tool is definitely the way to go here.

[dj01540i6sp]

( adjusting valves ) I'll agree that set cold gap is for when the engine dose warm up.

bmw is not anything like small engines like quads and dirt bikes. or any other engine for that matter
In the "books" for e30s it even says to do them when the engine is "stone cold"


and there is a difference between a hot engine and a warm engine

[CHIF8008]

bmw is not anything like small engines like quads and dirt bikes. or any other engine for that matter
In the "books" for e30s it even says to do them when the engine is "stone cold"


and there is a difference between a hot engine and a warm engine

[crazyman]

With all the engines I have built, both fuel injected and carbureted and small engines like quads and dirtbikes. I have found it best to do it when the engine is at normal operating temperature. In fact for most engines the specs they give you for proper valve lash is actually set at normal operating temperature. It takes an engine on average between 2 to 4 hours to completely cool down. That is more than adequate time to adjust valve lash. If you cannot do it in that amount of time you probably shouldn't be even attempting to do that.