Engine Rev Sound Is Different When @3000RPM

[FrustratedMunky]

Hey guys,

I don't know how to desribe it, it's quite subtle but it's enough to notice that something is weird. The engine tone is clear and crisp up until 3000RPM when it sounds as if something were coming in contact with a spinning object, like say if you turned on a fan and then you hold a piece of paper out to make contact with the blades while its spinning. Is this the timing chain tensioner? Is it something that I should be extremely worried about? It's not very distinct as of now, but I don't want it to get any worse and have an effect on my engine.

From the description of past problems with the tensioner, it sounds as if it may be that, but it's not a distinct "high pitched" sound, it just sounds like all of a sudden, a piece of paper is being held out in the path of a rotating object or something. The tone of the rev is... "rougher"?

Thanks in advance.

[kowalski]

does it do it when its in gear? when you pop the hood and do it where is the noise comming from?

[bmwdude]

Re: Engine Rev Sound Is Different When @3000RPM

Hey guys,

I don't know how to desribe it, it's quite subtle but it's enough to notice that something is weird. The engine tone is clear and crisp up until 3000RPM when it sounds as if something were coming in contact with a spinning object, like say if you turned on a fan and then you hold a piece of paper out to make contact with the blades while its spinning. Is this the timing chain tensioner? Is it something that I should be extremely worried about? It's not very distinct as of now, but I don't want it to get any worse and have an effect on my engine.

From the description of past problems with the tensioner, it sounds as if it may be that, but it's not a distinct "high pitched" sound, it just sounds like all of a sudden, a piece of paper is being held out in the path of a rotating object or something. The tone of the rev is... "rougher"?

Thanks in advance.

If it makes you feel any better, my fairly new M20 engine has the same charachteristics as you described. At 3000RPM, it suddenly gets more harsh. It is actually worse(louder) now than back before the head was rebuild. In my situation, I know for a fact, it is the HD valve springs and titanium valve retainers combo. Louder than with the stock parts.

How long have you owned this car? Did this just start? If it DID just start, then perhaps there is something to look into here. I wish I could hear it obviously. If it is the same sound as the one I have in mind, it is nothing. M20 engines are not noted for their silky sounding valvetrain soundtracks at higher rpms.

[kowalski]

you are supposed to get your valves adjusted eveery 20-40,000 miles on those engines i believe thats the milage inbetween.

[FrustratedMunky]

Umm it's been there for a while, but it's so subtle that I didn't really care too much. The majority of the time, it's there, but yesterday, it wasn't for some odd reason. I don't have to adjust my valves I believe since I have an M42 (?) so I don't know if it's that. I'll go and check where the sound is coming from. The sound is created throughout all the gears, and when it's in neutral.

[kowalski]

oo i thought you had the 6, no m42's don't have adjustable valves but the lifters do wear out, if you take them out and get a pen and it should have a minor bulge in the center. if not then you need to get the top refinished or buy a new one. they do make noise after a while mine does the same thing, i probably should'v changed them when i rebuilt the head but they were all fine. i think it may be the timing chain tensioner.

[bmwdude]

Sorry guy! I came to the automatic conclusion you had a 6. Silly me.

I have no experience at all with the M42. None whatsoever.