Low engine oil no engine knocking but a wobbling rubbing sound at high RPM?

[timmmaaa06]

Hello I did a stupid thing by not checking the oil and I ran the motor driving around town until a repetitive scratching sound was occurring at high RPM at which I would push the clutch and let go of the throttle. The sound would start soft and gradually increase with a wobbling rubbing scratching sound as RPMs increased when the RPMs goes down the rubbing sound decrease gradually. I brought the truck home safely and filled up the oil pan to the recommended level I safely ran the motor I heard nothing. In the cold morning I started the truck it ran and as I rolled out the truck started the noise again. I currently have the Head off the motor and the oil pan dropped with the valve covers removed. What are some things to be looking for I see no discolor on the piston connecting rods or score marks. They also are not loose on the crankshaft, if the problem is a valve what is the sign of a bad valve?

 

[mhassett]

I am thinking clutch throw out bearing.
MHassett.

 

[T. Highway]

Warn out Timing Chain or the camshaft is walking forward and back during RPM changes.

Bert

 

[Stan]

How low was the oil? My first thought from the sounds you describe was the throw-out bearing.

 

[GUNNY 155]

I am thinking throw out bearing on the clutch. Drop the inspection cover and see if you see anything the form of metal shavings or bits of clutch material. Also a good indicator of needing a new clutch assembly is to look at the both edges of the friction material on the disc on the flywheel side as well as the pressure plate side. You should see little slots spaced about 1 inch apart that are cut into the clutch facing material, if you do not see them the clutch disc is pretty well worn. In most cases the throw out bearing will last as long as the rest of the clutch components but two things will cause early failure. One is not maintaining proper adjustment which causes the bearing to ride and turn on the pressure plate fingers, the other thing is sub consciously riding the clutch pedal. As I told my daughter one time, that pedal on the left is not there for you to use as a foot rest.

 

[M543A2]

Do you remember if you had free play in your clutch pedal? There should be about 1 1/2" of free travel before you feel the release bearing contact the pressure plate fingers. If there is no free play then the relese bearing is constantly in contact with the fingers and will wear out quickly. If free play is nonexistent to the point it is bearing hard on the fingers it can cause the clutch to slip. If you had no free play it could be an indication you need to suspect the bearing. They can go out even with proper free play though. Make sure you have free play so the bearing is away from the fingers then try depressing the clutch pedal to see if you hear the noise when the bearing contacts the pressure plate fingers. If you hear it, the bearing is bad. Hopefully it has not stopped turning completely because then it can wear the tips off the fingers.
REgards Marti Sacks