Engine ? noise
 

I'm getting a noise I think is from the engine that is making me scratch my head, hoping somebody might have some ideas to try other than a teardown...
Here's the rundown; 350 4spd, I had 3.08 rear gears and at highway speed ran about 1900 RPM. Put 4.10 gears in it and now run close to 3000 RPM down the road.
The engine runs fine like it always has, but above 2500 RPM going down the road I'm getting a tap or rattle from the front. If I'm on or off the throttle it isn't there, but just rolling along it is. Can't get it to do it in the driveway sitting still either.
The noise is heavier than a lifter, but less than maybe a rod. Doesn't do it at lower engine speeds. Oil is clean, oil pressure where it always has been, have run it up to 4000 going up throught he gears and nothing, it will rattle in 3rd gear above 2500 rpm, but not on or off throttle. Backed the timing from 12 to 8 degrees to see if it was pinging, no sign of vacuum leak either.
Has me stumped.... wristpin maybe, bad input bearing in the trans?
Thanks,
Max

Re: Engine ? noise
 

You only hear the noise in high gear or in any gear just over 2500 rpm?

Re: Engine ? noise
 

I would check U joint back lash?? you know when its not under a load it may be slaping from push to holding back

Re: Engine ? noise
 

If you are sure it is from the front of the engine check the timing chain and the fuel pump pushrod\fuel pump. Check fan clutch and\or blades. All sound a little heavier than a lifter but not as bad as a rod bearing. Also had a harmonic dampner make a click style noise once, the bond of the dampner was loose. Check pulleys. Just some things to check.


Bryce

Re: Engine ? noise
 

Randy, will do it in 3rd also,
Hott, u-joints are new,
Bsteen, forgot about the pushrod/pump, have less than 20k on double roller timing set- will check balancer too,
Thanks

Re: Engine ? noise
 

Do you have to be going over a given mph to hear the noise?

Re: Engine ? noise
 

No, just over 2500 rpm, driving