L3400 motor question

[grizzjeeper]

I have a 05 l3400 HST with about 150 hrs on it. Its the bad serial number series

Here is my problem/question. When running at pto rpm the motor has what I would describe as a valve tap sound but at idle and up to half throttle sounds fine. I do not remember it making this noise and from what i can tell it varies in how loud it is.

Anyone have any thoughts or hear this? What to do?

Its always had good synthetics in it and barely even broken in. Obviously its over warranty.

 

[Marcussen]

What do mean by bad serial number? At PTO speed your RPM is probably about 23-2400 RPM, is the tapping that fast, in other words is it tied directly to the speed?

 

[grizzjeeper]

Tapping is directly related to engine speed, noise is faster as rpm's go up. I do not hear any tapping at all at idle and up to half throttle.

Bad serial number I mean I have the first year HST model. Crappy pto design, jerky 3pt hitch, poor pto engagement design. etc.

 

[art]

I normally have always heard to break an engine in on regular oil first before going to synthetics but I'd start with an oil change. Is the rap at crank speed or valve train speed?

I wasn't aware of all the problems with that model tractor.

 

[Fullfan]

I have a new l4400 with 10 hours on it. I am hearing the same tapping at higher rpms. Nothing below 1800, but it is real noticable at about 2400 rpms.

 

[grizzjeeper]

I noticed today that when tractor is not fully warmed up you dont hear it at any rpm. after its been ruuning a while it becomes more noticeable. Anyone have any ideas? I just dont understand why it only sounds that way at higher than 2k rpm.

 

[ibnxe]

I would expect what you are hearing is just valve tappet noise. When the engine is cold the oil is thicker and damps out the noise. Once the oil gets hot and the parts clearances open up the noise becomes more pronounced.
Have the valve adjustment checked and the problem should go away.