Recently started work on my project tractor, a 1986 Case 448 with an Onan B48M (18HP).
I'm getting some strange noises... And I can't decide what to do about it...
Wondering if I should leave this motor as-is, and just run it, or if I should pull the motor out, take it apart and see if I can figure out what the problem might be.
Here are the vitals, before I describe the sounds it's making...
Drivers side: 125 PSI
Passengers side: 105 PSI
Oil Pressure - Cold:
Bounces off 45 PSI (when relief valve kicks in)
Oil Pressure - Warm:
Idle: 18-21 PSI
Full Throttle: 30-34 PSI
Short history / whats been done so far:
Bought as running tractor (but barely), with plan to fix it for use in my garden (tilling and plowing), and in the fall to clean up leaves.
Motor was backfiring, could not get to run right. Poor compression. Found it had ingested two of the little screws from the top of carb, one per cylinder, and spit them both out. Minimal damage, however the valve seat on the passengers side had a groove across the seat.
Had a valve job done. Guy said he "lapped them in" (I latter read in manual this is not recommended). Did not replace anything in the valve train.
Eventually got motor running pretty good, motor has good power, starts easily, has a very slight miss about once every (I'm guessing) 10 revolutions.
SOUNDS ITS MAKING:
I'm trying to figure out what to do from this point...
Motor makes a fairly loud high pitched "clattering" noise, sounds just like valve clatter to me. Put a stethescope on the motor, high-pitched metal on metal tin-ey "clattering" noise is heard with about the same intensity from the valve area (both valves, both sides, exhaust valve a little louder), and the center back of the motor near the top (only place I can reach to listen). Also hearing a fairly loud "whirring" sound heard everywhere, sounds the same as the sound when a roller (ball) bearing is going bad.
To establish some kind of a "norm" I went and listened to my friends 446 (onan B43) with the same stethescope-- much quieter, valve-sound only very slight, with none of the whirring sound. his motor is definately not in great shape, and my motor is making a lot more noise than his, maybe 2-3 times as much.
My "valve clatter" noise is loud enough that people comment on it when they hear the tractor running.
WHAT TO DO?????
Should I RUN IT and hope for the best? Or TAKE IT APART and have a look?
Any thoughts and/or ideas are welcome!
Edited by Case448, February 26, 2016 - 10:03 AM.