Valve noise

[Unregistered]

Hearing a tapping that sounded like a valve out of ajustment, I cold-adjusted all the valves to 0.013", per info from Bentley and experts on this list.

After double checking all valves for correct settings, I ran the car. Exact same tapping sound after valve adjustment as before.

Could this be an injector?

Leaky intake or exhaust gasket?

Other ideas?

Please advise, and thanks.

[Tiger]

Synthetic Oil and Marvel Mystery oil... try it

[Unregistered]

Huh? Synthetic or Marvel Mystery oil? It's had Chevron 20/50 weight for years, according to the prior owner's indy wrench, who claims a thinner oil will leak, as the car has 235,000 miles. He also says a synthetic might be fire hazard.

Anyway, why would synthetic or Marvel cure the tapping sound? (Not that I disagree with you, but wanna know your reasons are.)

[Jake]

I don't mean to step on anybody's toes here, but I'm a not a fan of trying different additives and any "mystery" oil's to cure a tapping sound or low oil pressure. To me, this is a piss poor method of maintaining your car and only serves to temporarily cover up the problem. It may even lead to a more costly repair in the future if the noisy component is forced to remain in service. Diagnose the problem correctly first and then decide on the fix.

Unregistered:

Please include what engine you are dealing with. You say you adjusted the valve clearance so I assume you have an M20 or M30 engine. These particular engines do have noisy injectors as they get older. They sound just like excessive valve lash. The easiest way to check on the injectors is to get yourself an automotive stethoscope and listen to them. I'd bet you'll very surprised just how loud they really are.

Another possibility is a clog in the cam oil sprayer bar. You've been in there to adjust your valves so you most likely saw it and know what it is. As a preventative measure, I'd pull that off and spray brake cleaner through it (wear safety goggles!). Once you're confident it's clean, use a blow gun (wear safety goggles!) and clear out any residual brake cleaner and reinstall.

Additionally, that spray bar can come loose and rob you of oil pressure and reduce cam lobe lubrication. So keep that in mind when you pull it off. If it was loose it may be a good idea to Loctite it back in.

Speaking of oil pressure, I'm not sure if this affects the M30 engine as much, but I had one M20 come to me with a broken cam shaft. The cause? Loss of top end oil pressure due to massive bleed off from the rocker arm shaft plugs. Each rocker arm shaft is hollow and it carries oil pressure out to each rocker arm.

Each end of these rocker arm shafts are plugged, sometimes with a hex head insert. When I pulled this particular M20 apart I found these plugs had worked themselves loose and simply allowed oil pressure to bleed off to the point it robbed oil pressure from the cam. It probably didn't take long and cam eventually seized from the aft end breaking the cam in two pieces, right in the middle.

Most new rocker arm shafts now have plugs which have been soldered in to prevent this. Anyway, it's worth a quick look at least.

Hope this helps,
Jake Larsen

[Bill R.]

jake suggests if will be obvious as to which lobes are dry and starving for oil and if the banjo bolts that hold the spraybar down are loose then it will also be obvious, if thats the case, the front lobes on the camshaft closest to the radiator are the ones first affected and they will have a noticable groove worn in them... I doubt if its either of those because you would have noticed... Also take a stethoscope as jake suggested and narrow down the valves that are tapping..or use any piece of tubing that you can put your ear up to with the engine running. Once you determine which one it is, then remove the eccentric that you rotate to adjust the valve. If it has a flat spot on the eccentric replace it. A bad eccentric will make the tapping noise even when the valves are adjusted correctly. Bma can get them for you. If you really want to make sure that the oil spray bar is working correctly have someone crank the engine over with the power to the coil disconnected, after a few seconds you should be able to see if all the lobes are getting oil evenly.






I don't mean to step on anybody's toes here, but I'm a not a fan of trying different additives and any "mystery" oil's to cure a tapping sound or low oil pressure. To me, this is a piss poor method of maintaining your car and only serves to temporarily cover up the problem. It may even lead to a more costly repair in the future if the noisy component is forced to remain in service. Diagnose the problem correctly first and then decide on the fix.

Unregistered:

Please include what engine you are dealing with. You say you adjusted the valve clearance so I assume you have an M20 or M30 engine. These particular engines do have noisy injectors as they get older. They sound just like excessive valve lash. The easiest way to check on the injectors is to get yourself an automotive stethoscope and listen to them. I'd bet you'll very surprised just how loud they really are.

Another possibility is a clog in the cam oil sprayer bar. You've been in there to adjust your valves so you most likely saw it and know what it is. As a preventative measure, I'd pull that off and spray brake cleaner through it (wear safety goggles!). Once you're confident it's clean, use a blow gun (wear safety goggles!) and clear out any residual brake cleaner and reinstall.

Additionally, that spray bar can come loose and rob you of oil pressure and reduce cam lobe lubrication. So keep that in mind when you pull it off. If it was loose it may be a good idea to Loctite it back in.

Speaking of oil pressure, I'm not sure if this affects the M30 engine as much, but I had one M20 come to me with a broken cam shaft. The cause? Loss of top end oil pressure due to massive bleed off from the rocker arm shaft plugs. Each rocker arm shaft is hollow and it carries oil pressure out to each rocker arm.

Each end of these rocker arm shafts are plugged, sometimes with a hex head insert. When I pulled this particular M20 apart I found these plugs had worked themselves loose and simply allowed oil pressure to bleed off to the point it robbed oil pressure from the cam. It probably didn't take long and cam eventually seized from the aft end breaking the cam in two pieces, right in the middle.

Most new rocker arm shafts now have plugs which have been soldered in to prevent this. Anyway, it's worth a quick look at least.

Hope this helps,
Jake Larsen

[Unregistered]

Checked the valves again today. Then removed the spray bar, cleaned it with WD40, brake cleaner fluid, dental floss, pipe cleaners, and a vacuum cleaner. It appears the spray bar may have been installed backwards, but it is definitely in correctly now, and is unobstructed.

The "valve" noise continues, so I suspect it may be an injector. However, when revving the engine and then backing off (while in neutral), the tapping noise continues (apparently from just one cylinder) as the engine winds down, then virtually disappears at idle RPM. Seems to me that if it is a noisy injector, the tapping noise would pretty much stop when the engine is spooling down after revving. Likewise a leaky exhaust gasket noise would attenuate as the engine winds down.

The car is due for an oil change, and I'm wondering if I should try a lower viscosity in the new oil. The car has been using Chevron 20/50.

Jack's suggestion that one of the valve rocker eccentrics has a flat spot is on the list of suspects. Any other suggestions would be much appreciated.

Meanwhile, I'm looking for suitable stethescope.

[Bill R.]

Checked the valves again today. Then removed the spray bar, cleaned it with WD40, brake cleaner fluid, dental floss, pipe cleaners, and a vacuum cleaner. It appears the spray bar may have been installed backwards, but it is definitely in correctly now, and is unobstructed.

The "valve" noise continues, so I suspect it may be an injector. However, when revving the engine and then backing off (while in neutral), the tapping noise continues (apparently from just one cylinder) as the engine winds down, then virtually disappears at idle RPM. Seems to me that if it is a noisy injector, the tapping noise would pretty much stop when the engine is spooling down after revving. Likewise a leaky exhaust gasket noise would attenuate as the engine winds down.

The car is due for an oil change, and I'm wondering if I should try a lower viscosity in the new oil. The car has been using Chevron 20/50.

Jack's suggestion that one of the valve rocker eccentrics has a flat spot is on the list of suspects. Any other suggestions would be much appreciated.

Meanwhile, I'm looking for suitable stethescope.

[winfred]

if jack helps you off your horse, should you help jack off his horse?


I don't know Jack, who's jack?

[George M]

hilarious...good one Winfred. How many on this board know Jack?
George

[Unregistered]

Checked the valves again today. Then removed the spray bar, cleaned it with WD40, brake cleaner fluid, dental floss, pipe cleaners, and a vacuum cleaner. It appears the spray bar may have been installed backwards, but it is definitely in correctly now, and is unobstructed.

The "valve" noise continues, so I suspect it may be an injector. However, when revving the engine and then backing off (while in neutral), the tapping noise continues (apparently from just one cylinder) as the engine winds down, then virtually disappears at idle RPM. Seems to me that if it is a noisy injector, the tapping noise would pretty much stop when the engine is spooling down after revving. Likewise a leaky exhaust gasket noise would attenuate as the engine winds down.

The car is due for an oil change, and I'm wondering if I should try a lower viscosity in the new oil. The car has been using Chevron 20/50.

JAKE'S suggestion that one of the valve rocker eccentrics has a flat spot is on the list of suspects. Any other suggestions would be much appreciated.

[Tiger]

Synthetic oil has a much higher spec than dino oil... so fire would be the last thing for synthetic. Dino oil would cook before synthetic will.

Anyway, back the the question. I suggested synthetic because synthetic fluid has a better flow (thinner) and will get to those area where oil might have starved the valvetrain. The detergent property of the synthetic might help clean up those spots.

Mystery Oil is something I just decided to use... it is a thin oil and is probably has a better quality to become a vapor that travels the air passage of the PCV system... which might help lubricates and dislodge any obstruction in the system. You can use Mystery oil in gasoline too... to lubricate the fuel pump, fuel injector, and helps clean the valves.

I did this on my 201,000 miles MB... which never had any synthetic oil in its life. No leak and it fixed my hesitation problem which is caused by valve problem. I think it was my hydraulic compensator was sticking or stuck in position where the valve couldn't open big enough and cause misfiring. After one nice trip around the town, it totally disappeared.

The car ran alot better after using synthetic oil... more power... In the beginning, the valves would be loud... tons or rackets... but after 300 miles, they settled back to my usual tappings... maybe quieter. I had that usual tappings since I bought the car at 112,000 miles.

Using such a highly concentrated cleaner such as carburator cleaner or fuel injector cleaner can cause problem... which is what I did on my car... don't ask me how in the world fuel injection cleaner affected my valve... well it just did...as soon as added the fuel injector cleaner (cheapo synthetic valvoline FI cleaner) to remaining 3 gal in my tank, I started to have that problem.

So it is important to lube the carb with WD40 on carb... (on my folks old caddy, I did this and ****... carb got stuck on full throttle when I gunned it... can u imagine... full throttle stuck... I checked all the linkage and normal... until i moved the linkage back and forth until I heard a clink (metal shutting inside the carb)... that's how strong the carb cleaner is today... it cause sticking because metal so clean.

Mystery Oil will do the same for you in fuel injection system. Only lube it at the last resort... follow the label on how much to add.

It may seem like piss poor solution to fix your problem... but I'll tell you what? It will do NO harm to your engine and its component. If it works, think how much money you just saved compared to having a mechanic trying to figure out what is wrong with the engine... change unnecessary parts.... draining your pocket in the meantime while they are stumped.

If you are wondering how I came to this solution... I did it as the last resort... I checked all my spark plugs... spark plug wires resistance... lubed all my throttle linkages... timing... and noticed that the valve are tapping louder... Instead of calling up BMA to start ordering normal tuneup parts which I knew wouldn't make any difference... I thought I'd give this a shot first.

My cost? Two bottle of mystery oil...$8... and the synthetic I drained from my BMW that had only 5000 miles usage... I figured if it doesn't work or leaks, then I can just drain it out without wasting my money.

[Tiger]

Sorry for my grammar but at least you get the idea.

[winfred]

marval m o is pretty much atf, people have been using atf as a fuel addetive for ages, does wonders for a crap carb

[Tiger]

oh... didn't know that... if it does wonders for carb, it should help FI too... like CIS fuel injection system. At least Marvel M O doesn't stink like ATF when burned...

[Jake]

Synthetic oil has a much higher spec than dino oil... so fire would be the last thing for synthetic. Dino oil would cook before synthetic will.

Anyway, back the question. I suggested synthetic because synthetic fluid has a better flow (thinner) and will get to those area where oil might have starved the valve train. The detergent property of the synthetic might help clean up those spots.

Logical yes, but it's not exactly that cut and dry. The thing is, by the time using thinner oil is life or death for an oil starved component (due to slug/carbon build up), it's a day late and a dollar short. Seriously, I'm not trying to be a smart ass or anything. This is just a common misconception. Good natured, but just a little off.

The main problem is if you have slug/carbon build up to the point your starving your engine of oil, dislodging that crud can really cause some problems. All the debris in the oil, it has some real potential to cause even more damage. Use it at your own risk, but don't assume that because it cured that annoying noise you were trying to get rid of that its completely safe.


Mystery Oil is something I just decided to use... it is a thin oil and is probably has a better quality to become a vapor that travels the air passage of the PCV system... which might help lubricates and dislodge any obstruction in the system. You can use Mystery oil in gasoline too... to lubricate the fuel pump, fuel injector, and helps clean the valves.

My friend, you do realize you are stretching it just a *tiny* bit don't you? :D "...better vapor that travels the air passage of the PCV system..." This is a new one for me. :p "...which might help lubricates and dislodge any obstruction in the system..." Please see my above explanation on dislodging obstructions in your engine.

"...You can use Mystery oil in gasoline too... to lubricate the fuel pump, fuel injector, and helps clean the valves..." Have you ever used gasoline to clean oily parts? I don't mean to point out the obvious, but what do think it's going to do for your fuel pump? It's not going to lubricate it. With a constant flow of gas through that thing I guarantee you it's the cleanest thing in your car. It may help your valves a bit and may do something for your injectors, but that's about it.


I did this on my 201,000 miles MB... which never had any synthetic oil in its life. No leak and it fixed my hesitation problem which is caused by valve problem.

Now this I would agree with. Probably a result of cleaning up the valves and injectors a bit.


The car ran alot better after using synthetic oil... more power...

Yes. Synthetic oil definitely feels better. I recommend it unless the engine has heavy internal build up. It will loosen crap up so beware.


Using such a highly concentrated cleaner such as carburator cleaner or fuel injector cleaner can cause problem... which is what I did on my car... don't ask me how in the world fuel injection cleaner affected my valve... well it just did...as soon as added the fuel injector cleaner (cheapo synthetic valvoline FI cleaner) to remaining 3 gal in my tank, I started to have that problem.

Too much of a good thing my friend. You are supposed to add it to a full tank of gas. This is one of those things where too much is a bad thing.


I checked all the linkage and normal... until i moved the linkage back and forth until I heard a clink (metal shutting inside the carb)... that's how strong the carb cleaner is today... it cause sticking because metal so clean.

I wouldn't say it was from the metal being so clean, but more from the absence of "filler". :D You got all the gunk out of there, now there's play and binding from improper mating.


It may seem like piss poor solution to fix your problem... but I'll tell you what? It will do NO harm to your engine and its component.

Now I will get critical here. You are not a professional and you simply do not have the experience to make that claim. It isn't a coincidence that other professionals would disagree with your logic. You are on a public forum telling everyone "it will do NO harm to your engine and its component". Please understand, and I'm very sincere when I say this, your comment is a liability. Advice like that can get someone into trouble. Please keep this in mind.

If you speak from years of experience as a professional auto mechanic, I apologize and will humbly retract everything I've said; but in my experience this not good advice.

In the end, it really is to each their own. It's ok to suggest, but you've got to be careful. Stating rumors, hunches, and/or assumptions as fact can catch up to you in the worst way. I love public forums but remember we live in a sue happy world and people can take you to court over the dumbest things. Like... "Your Honor, he portrayed himself as an expert among experts and as a result of his advise my engine is destroyed..."

So if you like to fiddle around in the garage and play with this or that, please do. There's a lot of fun to be had! Just be safe!!

Take care,
Jake Larsen

[Uncle Paully]

Hearing a tapping that sounded like a valve out of ajustment, I cold-adjusted all the valves to 0.013", per info from Bentley and experts on this list.

After double checking all valves for correct settings, I ran the car. Exact same tapping sound after valve adjustment as before.

Could this be an injector?

Leaky intake or exhaust gasket?

Other ideas?

Please advise, and thanks.

[Uncle Paully]

could the valves be loud because the adjustment is a bit loose? they do say that loud valves are happy valves, but maybe the noise your hearing is different than that.
good luck

[Tiger]

Ur just a smartass... 16 years of serious mechanic over here. I would figure out **** before u smartass start scratching ur ass.

[Unregistered]

could the valves be loud because the adjustment is a bit loose? they do say that loud valves are happy valves, but maybe the noise your hearing is different than that.
good luck

I set the valves at 0.013" cold setting because others on this list have noted that seems to be the accepted happy medium among BMW experts. OTOH, Bentley says to use 0.012" cold setting. Perhaps I should re-set to 0.012".

However, as to the tapping noise: It's only one cylinder, and since all were set to 0.013", one would think there would be more than one tapping noise source. It has been pointed out on this list that an eccentric with a flat spot will also make tapping noise, even if set with proper gap. Anybody know what new eccentrics cost?

My setting technique maybe faulty: With cam lobe pointing at crankshaft, I loosen the eccentric nut, slip in the 0.013" feeler gauge, rotate the eccentric until snug, then tighten the nut. Now, the 0.013" gauge is a bit tight when pulling it out, but a 0.012" gauge slips in fairly easily. Please tell me if this is an incorrect method.

[George M]

Your method for adjusting your valves is OK. For the single noisey cylinder, replace the intake and exhaust valve eccentrics and a good chance that will resolve your issue. They are inexpensive and the first thing you change if you can't quiet a noisy valve set to the proper clearance. Call BMA and mention my name.
George

[Bill R.]

>013 is to improve the idle quality on the m30... By increasing the clearance .001 you make a slight difference in the intake and exhaust valve duration and reduce overlap slightly.. It usually makes a noticable difference in the smoothness of the idle... If you choose to you can set the valves to .012 with no harm , you may not like the idle however..
Call bma and find out how much the eccentrics are, its an 800 call and only takes a minute, if memory serves me they are very cheap. I would pull the eccentrics on the valves that you hear the tapping and see if they appear damaged, at the same time check the rocker arm for excessive play while the eccentric is out and inspect the surface of the rocker where it rubs on the valve stem and the cam for damage.







I set the valves at 0.013" cold setting because others on this list have noted that seems to be the accepted happy medium among BMW experts. OTOH, Bentley says to use 0.012" cold setting. Perhaps I should re-set to 0.012".

However, as to the tapping noise: It's only one cylinder, and since all were set to 0.013", one would think there would be more than one tapping noise source. It has been pointed out on this list that an eccentric with a flat spot will also make tapping noise, even if set with proper gap. Anybody know what new eccentrics cost?

My setting technique maybe faulty: With cam lobe pointing at crankshaft, I loosen the eccentric nut, slip in the 0.013" feeler gauge, rotate the eccentric until snug, then tighten the nut. Now, the 0.013" gauge is a bit tight when pulling it out, but a 0.012" gauge slips in fairly easily. Please tell me if this is an incorrect method.

[George M]

haha...brilliant(?) minds think alike.
LOL,
George

[Bill R.]

also....:)





haha...brilliant(?) minds think alike.
LOL,
George