K301 Drive Pulley - how close to block?

[Jeff-C175 7,202]

Doing some more investigating on the 'big tick project', trying to determine the source of the 'rattle' or 'tick' that I talked about in another thread, I spent some time listening for where the noise seemed to be the loudest.

 

As it turns out, it seems loudest directly behind the PTO bell.  When I took a closer look, I noticed that the drive pulley seems terribly close to the block:

 

 

 

Here's a view from the front:

 

 

Somehow I don't believe this is correct!

 

How far away should that pulley be from the block?  I wonder if this is the source of the noise?

 

I'm going to pull the PTO bell, and clutch plate tomorrow and do some more investigation.

 

I wonder if that pulley is LOOSE?  

 

Need to hit the service manual because I'm not sure what secures it to the crankshaft.  I think I can see a set screw when I peer down between the pulley and the clutch plate.  I'm guessing that there are TWO set screws?

 

What say you K301 experts?

 

Edited December 7, 2021 by Jeff-C175

[oldredrider 2,548]

A 1/16" clearance between pulley and block should be sufficient. There are two set screws on the pulley hub to hold it in place.

[Jeff-C175 7,202]

11 minutes ago, oldredrider said:

A 1/16" clearance between pulley and block should be sufficient. There are two set screws on the pulley hub to hold it in place.

 

How much axial end play should there be in the crankshaft?

 

I wonder if it's possible that while it's running that it could be moving inward and the pulley is bouncing off the block?

[oldredrider 2,548]

Between .003 and .020 end play on the crankshaft.

Edited December 7, 2021 by oldredrider

[Jeff-C175 7,202]

5 minutes ago, oldredrider said:

Between .003 and .020 end play on the crankshaft.

 

I'm going back out to check it out.

 

 

[kpinnc 12,085]

Seems I remember somewhere saying 1/4 inch space on the drive pulley...

[Jeff-C175 7,202]

Uh-huh... evidence of contact!  Not 'heavy' contact, but POSSIBLY enough to cause the noise I was hearing.  

 

I moved it out about ohhh... maybe 3/16" clearance, I have it mostly back together but can't run it until tomorrow to test.

 

 

Note that the upper right doesn't appear 'fresh', but the lower right possibly is.  Upper left could just be 'dirt' between the pulley and the block, the paint isn't really chipped much, and about the same as lower left.

 

Further evidence that this MAY be the noise is the fact that when I was using the PTO bushing as a slide hammer to tap the pulley back into place the sound was almost EXACTLY what I was hearing!

 

Here's hoping I got Pandora's box closed up again !

 

[Jeff-C175 7,202]

Well... that didn't make any difference at all.  I actually didn't think it would, but it didn't hurt to hope!

 

Isn't the internal governor mechanism right in that vicinity also?  Does that ever make 'rattly' noise?

(and it is most certainly not adjusted correctly!)

 

Trying to rule out everything else before putting on the wet suit and tank and jumping in.

 

 

 

Edited December 7, 2021 by Jeff-C175

[oldredrider 2,548]

You could be possibly looking at bad balance gear bearings. They "rattle" when heading South. 

[Jeff-C175 7,202]

25 minutes ago, oldredrider said:

You could be possibly looking at bad balance gear bearings. They "rattle" when heading South. 

 

That's what I've been thinking all along actually.  

 

Just trying to avoid pulling the engine and dropping the pan if it's not nesskissary.