Need input on unusual engine noise

[Tom F&L GoR]

Within the span of two city blocks, I started to hear a loud chirping noise. At first I thought it was something rubbing on a wheel or wheel bearing, but at the next stoplight it didn't go away. By the following light it was easily loud enough for me to hear all the time over the 3" exhaust. I pulled into a parking lot and the chirp was so loud and had a sharp "ring" that I couldn't tell where it came from; front half and inside the block is all I could guess.

Got home, released tensioner and loosened the serpentine belt - noise still there. It's related to engine speed, although a low frequency, like maybe cam speed or rocker arm? It seems to sound the same from standing on either side of the engine, no difference when removing oil fill cap or breather hose to listen, the volume doesn't change with engine speed. It hasn't gotten louder (60 seconds to begin, but after 10 minutes to get home, it's not worse.) If you were deaf, you wouldn't notice anything different. Oil pressure, oil temp, coolant temp are normal. No unusual smell.

I suspect something is rubbing, but it sounds like steel on steel with no oil. There aren't that many places where something steel can rub on something steel, though. Maybe a timing gear is rubbing? Any Gen 3 experience?

The only thing I can compare it to is when I had a rebuilt 318 and they put in a rocker arm shaft upside down. The oiling holes sprayed oil in the rocker cover rather than between the shaft and the rocker arms, so it started squeeking pretty quick. But this noise is much louder and sharper.

~73,000 mile Gen 1, lots of use, little abuse, good maintenance. Any ideas?

 

[Ron]

Might be interesting Tom to check the drain plug magnet or cut open the oil filter. What about a broken valve spring?

 

[Tom F&L GoR]

Runs too well, Ron. No vibration, no miss, no stumble or hesitation. Something else that was similar on another vehicle turned out to be the clutch/torque converter inspection cover had gotten hit and was rubbing on the backside of the flywheel. Except this is louder.

 

[David]

I'd use one of those mechanic's stethoscopes. They often have a tube attachment which allows you to pinpoint sounds to their source. Since I can't hear the sound -- I can only guess... I have heard exhaust leaks that sounded like taps and later chirps as the crack widened... I HOPE it's not that. You can get pretty close to the source of a sound by just using a rubber hose held to your ear. Watch it doesn't get caught in the serpentine belt!

 

[Ron]

Tom,

Was told the flywheel bolts have been known to back out if ever reused, but since the sound seems front / center engine, probably not....

Keep us posted

 

[Ulysses]

I once had an idler pulley go bad that sounded just like that.

 

[Tom F&L GoR]

It does sound like a pulley, but I had the belt off and the sound is still there. Think of that sound about a foot behind the belt. It's louder from up top than underneath. It's in the "V". Oddly, it's not getting louder, despite how quickly it started. The Wizard thinks maybe a roller lifter that stopped rolling, which is ugly since you have to remove heads to get them out and also replace the cam. Anybody ever "hear" a non-rolling lifter? I would have guessed it more of a grinding sound, this is a shrill chirp sound.

(sound like will have to sell a lot of brakes... )

 

[Bill B]

It Anybody ever "hear" a non-rolling lifter? I would have guessed it more of a grinding sound, this is a shrill chirp sound.

I have and it was more of a muted squeal/grinding noise. Have you tried to VERY slowly depress the clutch while the engine is running to try and "feel" the noise?

 

[Cris]

Roller lifters do not roll well if they are turned. That can happen if the yoke somehow fails.

Do you have any debris in the oil? That can quickly confirm if you have something wrong internally such as a cam bearing, lifter, rocker, piston, etc. If you do check the material (alum, steel/iron, etc).

Is it temperature related? Such as starts only after running for a few minutes. Loudest initially after start, etc?

Any change clutch pedal in or out?

Does it seemed to have a defined pattern such as once per revolution?

Just some random thoughts.

 

[CMilViper]

I have had a vehicle with what sounds like the same noise....It was coming from the harmonic balancer area....They said it was a sensor shaft or something like that???

 

[Tom F&L GoR]

Thanks for the ideas, everyone.

I removed the oil drain plug and the magnet has several needle bearing rollers on it. I guess Chuck got it - failed roller lifter, or perhaps the yoke failed and let the lifter rotate. Still surprised at the high pitched squeal. Or maybe that's the car crying.

Ron, sorry, I dismissed your comment and you were right.

Anyone with spare valvetrain parts, let me know.

 

[Bad_Byte]

I just tossed an entire set of OEM rollers and honestly I'm glad I did. Although, I put OEM back in the design of the oil port for the new lifter is better. If I remember correctly the oil port was on the bottom (or maybe the side) for the original lifters and with the newer part number it is on the top. The old ones used to bleed down pretty quickly. The new ones don't seem to have that problem. New lifters are only around $12 each. I think its well worth the effort to replace all of them.

I think one of your biggest expenses will be head gaskets unless you rebuild the heads.

Hopefully the cam isn't destroyed.

Good luck Tom

 

[Ulysses]

Glad you found it, bummed for ya' that it will cause some down time.

 

[Viper Specialty]

check for a loose cam position sensor, if the bolt comes loose that holds it in place, engine vacuum can **** it into the engine, causing it to rub on the cam gear. Eventually, it will wear it away until it breaks it, or snap it off if it gets sucked in far enough.

 

[newredrt10]

If it is a lifter that has failed or turn, check the lifter hole for out of round. A lifter turned on mine and the block had to be machined. Also the lifter may have damage the cam.

 

[Tom F&L GoR]

Luckily I bought the "good" head gaskets a while ago. However, the man-hours to remove intake, heads, chain case cover, etc is looking large.

Finding the needle bearings on the magnet, I am assuming the cam lobe is badly wounded.

Does anyone know if the Gen 2 cams fit in Gen 1 blocks?

newredrt10, what was the cause of the lifter turning?

 

[newredrt10]

The bolt that holds the lifter retainer in place came loose. You might want to do a leak down test before you remove the heads. It will tell you a lot about the motor.