Bad Knocking/Rattling Sound - BMW Forum

JoeMadoo · 03-08-2006, 07:10 PM

In the past few weeks, I've noticed a horrible Rattling sound coming from either my valve cover or intake manifold. It seems to be getting louder as time goes on. I adjusted my valves twice to spec (.25mm). It goes away after about 1500 RPMs or so, but its very annoying at idle, especially low idle at about 600. I recently rebuilt this engine, new gaskets, hoses, cleaned.

Thanks to anyone who has any advice. I'm thinking about recording this rattle and uploading it if that will help at all.

Starmavin · 03-09-2006, 08:23 PM

Sounds most like the rockers are not holding their adjustment, use lock-tite on the nut. Also put a scratch mark on the stud side of the adjuster to see if it didn't strip out. Rare, but it could be a cause. The last thing is to start it with the valve cover off for a moment to make sure that the oiler is squirting where I should.

JoeMadoo · 03-13-2006, 11:08 AM

Well when i double checked the valves a few weeks later they were in the same position. I did start it with out the valve cover, the oil squirters seem to be working fine. It sounds like its coming more from the intake manifold because when i ran the car without the valve cover, the sound didnt change at all...

Starmavin · 03-13-2006, 07:09 PM

Tough one. And the car runs good? No idle problems?

JoeMadoo · 03-13-2006, 07:43 PM

It runs fine... The idle fluxuates from about 800-900, but it's done that for as long as I can remember. The raddle sound isnt linier with the clicking from the valves either, it dosent seem to have anything to do with the head. I took off my T/B, ICV, Cold Start Valve, AFM, and cleaned the crap out of it. I might take the intake manifold off tomorrow, that seems to be where its coming from.
It's more embarrasing than annoying, you can hear it from 100 feet away.

ldsbeaker · 03-13-2006, 09:43 PM

OT: what kind of suspension do you have to accomplish the 1.6" drop? ... and while you're recording your rattle, can you record your magnaflows? maybe a flyby, and a couple revs from idle? I'm curious to hear it. Dude, are you on R3v or E30tech?

JoeMadoo · 03-13-2006, 10:33 PM

Sure Man. Ill put them on my site and post some links tomorrow.
I bought B+G Springs off Ebay for about $150.
I'm kinda new to the forums thing, this is the first site I signed up for...

JoeMadoo · 03-14-2006, 07:03 PM

Here are a few mp3's and an MPG:

Next to Exaust:
http://www.cheeseware.com/mp3/exaust1.mp3

Underneath Exaust:
http://www.cheeseware.com/mp3/close_exaust.mp3

Pulling Away:
http://www.cheeseware.com/mp3/start.mp3

Driving Towards the Camera:
http://www.cheeseware.com/movies/aproach.mpg

I couldn't really record the rattle becuase the valves kinda block it out...

Rfitz25 · 05-08-2006, 03:39 PM

Hello,

(Hey Starmavin

)

Good thread I think I hurt my valve train this weekend.

Got new springs, shocks, awesome, ran an autocross yesterday, hauled butt. totally different car. very flat. What a blast. On the rev limiter in the last section every run, 2-3 pops. (got 6 runs in)
Didnt think this would hurt anything.

After parked it, got my helmet off,
started it up for fun runs, had a bad loud ticking. uuuuggghhhh....
Skipped the fun runs and limped home at 2-3k rpms to be safe..
Runs fine but scary tap tap tap sound.
Kinda goes away as revs go up.
I think its coming from under the valve covers.
I'll try and check it out tonight.
Hope its just adjustment or some parts I can get oo without taking off head.
My mechanic suggested 30/100ths of a mm on the valve clearance instead of the spec (28 I think?).
He thought it sounded like the valves were too tight before at idle.
Maybe he was right.
He said he always does this when he does a valve job on an older E30/M20's

Thanks for any sugestions.
I'll try what Starmavin said tonight.
If i stripped the adjuster I can replace it right?

I'll read the Haynes manual tonight adn get some more tools.

lock-tite
90 feelergauge
new gasket??
etc

,Richard

JoeMadoo · 05-09-2006, 01:14 AM

Hey, im sorry to hear that. I found out what my rattle was a while ago.

I noticed the power steering pump was shaking alittle bit and so was the crank hub. I went under to see what i can see and 3 out of the 6 crank hub bolts were missing, and the 2 of the remaining 3 were hand loose. There was one left the was somewhat tight. Also one of the 4 bolts that mounts the Power steering pump was also missing. So i got some new crank bolts and a power steering bolt, torqued them to spec this time :-), and the rattle was gone.

It sounds like your click is your valves if it is constant. Also check to see anything shaking.

Rfitz25 · 05-09-2006, 02:03 PM

Hey guys,

I found my big ticking.

Thanks for all the posts, they helped.

One front exhaust port rocker arm had slipped forward along the rocker arm shaft and was riding only half on the cam shaft. I slid it back and the retaining bracket clicked into place and it ran fine.
I'm hoping the last guy did a valve job and just didn't seat it right.
If it happens again I'll try and replace the retainer and spring etc.

Hey how do you check the valve clearance? Get it on a flat spot of the cam and put the feeler gauge between the rocker arm and valve stem???
I couldnt get the gauge into it?
( BTW Second gear worked fine to roll the motor/cam around)
My mechanic said to set them to 30/100ths of a millimeter, looser than spec?. This seems thin. Whats the spec? ('87 325is)
Haynes manual wont tell you how to do it. LOL :lol:
Maybe I need the Bently manual.??

I'll look for more loose bolts on power steering etc like you suggested too.
Good idea.

Cheers,
Richard

JoeMadoo · 05-10-2006, 01:52 AM

Spec is .010 inches or .25 mm. They are painless to do, i got a set of bent feelers, that makes it a bit easier.

Rfitz25 · 05-10-2006, 05:16 PM

Mr Magoo,

Thanks a bunch.

Now it makes sense.

mechanic said 30 100ths of a mm he must have meant 30 tenths of a
mm == .30mm
I have one gauge thats .305 should do the trick but .25 sounds like it would work better. Sinse smaller is quieter and more power?

Might try again tonight.

I think the spec on the 325is might be .28 not .25 have to look it up.

Yeh I read another post and bought the 45 degree feeler gauges.

Much easier to get in and out.

(...thats what she said) lol

BTW. looked for loose bolts last night and found broken vacume hose on intake. replaced it, much smoother idle. Must have broke it Sunday.

I also think I stretched my throttle cable and the lock nut is missing on the other cable that I dont know what it is. goes t some weird black contraption in front left corner. tightened em both, runs good, need to find one of those tiny tiny nuts. Probably should ad a lock washer maybe? or a little locktight.
Looks like it backed off and fell off.

Only had the car month, still learning some of the systems.

Hauls butt though.

Cheers,
Richard

JoeMadoo · 05-10-2006, 06:07 PM

Awesome, glad to hear its runnin good!