Valves?

[Predzy743]

My valves are very loud. Do you think i need a valve adjustment? It sounds like its running without oil. Also how do I do this?

-Steve

[Sagaris]

Could be worn engine bearings, low oil/oil pressure, exhaust manifold leak, noisy fuel injectors, valves out of adjustment, worn valve guides.


Use a stethoscope or at least a broom handle and listen around the engine to try and pinpoint it. If you still think its the valves, adjust them. If you are like me and they are still noisy after adjustment (P.O. must have slacked on valve adjustments ) run Lucas upper cyl. lubricant in the gas. It will make the engine noticably quieter.

[Predzy743]

Sagaris. Thanks for the fast reply.. I know the sound is definately behind the valve cover, no leaks on the manifold, and its not a knock so its not lower end. It would onwed by a girl before me, She was the first owner, so I bet the valves are out of adjustment. It runs a bit rough too.. What can I do to smooth the idle? Thanks man

[jclar]

I've got no clue as to whether or not this is actually the problem, but if your valves do need to be adjusted this is a pretty good write up on how to do so:
http://www.pelicanparts.com/bmw/tech...lve_Adjust.htm

[Predzy743]

Thanks jclar! I think m20b25's are just noisy motors. But still it runs rough. So maybe the vlaves

[e30:)]

i would adjust your valves, my eta is silent... if your m20b25 is loud then something isnt right.
edit: you could also be looking at a vacume leak. my intake gasket was bad and my car would idle low and sound like it had a bad knock and after i replaced it, it went away.

[Predzy743]

awesome. Thanks for the info!!!!

[E-Thirty]

You'd be surprised how much noise comes from worn injectors! Take a long screw driver and put one end against your ear and the other against a fuel injector.

[jlevie]

Valves should be adjusted every 10-15k, so they probably need adjusting. But even when properly adjusted the valves will make noise if the guides are worn. That doesn't hurt anything, though it can cause a bit greater oil use and a slight reduction in power.

[CorvallisBMW]

You'd be surprised how much noise comes from worn injectors! Take a long screw driver and put one end against your ear and the other against a fuel injector.

Ya injectors can often make clicking/ticking noises just like valves. If you still have the noise after doing the valve adjust, this would be my next recommendation.

As was stated before, run some of that Lucas Upper Cylinder Lube for a few tanks. It comes in a big bottle, and only takes about 3oz per fillup. Should go for 10 tanks or so. Also do a Seafoam treatment (just search seafoam here on r3v, lots of threads)

[MR 325]

i would adjust your valves, my eta is silent... if your m20b25 is loud then something isnt right.

B25 engine always have more valve noise than B27 engines.

[Predzy743]

Ok cool. Now will worn injectors cause a lack of power? Also my idle is pretty rough. I put new plugs in and it made the throttle response better, then I modded a set of eta 8mm wires to work in my b25 and it made things better too. Now all thats left is the cap, rotar and the o2 sensor. Should that make the idle smooth? or with the valves cause a rough idle too?

Thanks!

[CorvallisBMW]

Just do all of it.

[brianpgriset]

I had similar issues to you. I found several small vacuum leaks and my idle has stabilized considerably. Also clean your ICV. Go ahead and start replacing vacuum hoses. Do the valve adjustment. It is easy and should help the ticking. Also, when I switched to synthetic oil it considerably quieted down the valve noise, if you don't already use it.

Finally, it just seems that the m20b25 is a ticky motor. It took me awhile to get used to it, but if you do all the mentioned items in the thread you should feel pretty good.