Engine drive plate hub mount position
 

Dose anyone know if the hub slot wears more slowly if mounted in a specific position with respect to TDC? There are 2 mounting position options and the thought crossed my mind.

I looked at the 149 manual and it doesn't specify either. In the years past I never really considered this, but it dose wear faster than I would like.

Mike

I have absolutely no idea what you are talking about. What hub? The one on the rear? I can't think of anything that can be bolted on two ways..... How about some more info. And maybe some pics. You mentioned a 149, so a K321 right?

I'm not saying that it isn't possible, but in all these years, I have never heard of anyone mounting the adapter a certain way to make it wear slower.

It would be nice if it were true though.

I kind of figurer that its a long shot, but the aluminum pulley is pinned to the flywheel, and the tapped holes within are cast in the same location on the few I have hanging around. With that and my thought that IH/Kohler didn't just guess at the place to cast those hole makes me wonder. Plus after combustion, and as the mix is compressed the loads on the crank change, and could be transferred into the hub affecting the wear pattern. I really don't know, but I thought it was worth considering.

Mike

Dang Mike, I guess I'm not the only one that thinks like that ! Good question.

The hub is a circle guys. It doesn't matter. It would wear the same no matter what. It's like a flywheel and clutch. You can bolt it on 6 different ways, but the wear pattern would never change.

Best I can tell your right about that but it doesn't keep me from over thinking the simplest things. Maybe I should see someone about that? LOL

I don't disagree with what your theory, at some point there has got to be a difference. I was thinking more along the lines of a vibration factor.

However, I believe that the alignment of the engine in relation to the drive shaft along with maintaining a smooth running engine, is probably about the best friend you are going to find concerning the wear issue on the adapter, drive shaft and pin.

All in all, getting 40 or 50 years of service out of one of these little machines is still pretty impressive.

J, Your right, the hub is a circle, but it has a slot in it. The slot changes the equation because it now has a fixed point of attachment rather than a rotating circle. Kind of like saying the main journal is round and it shouldn't wear at one point over another.

It very well may not make a difference but I think dismissing the theory would be ignorant.

Mike

Main and rod journals have "side" load on them. The hub has "rotational" load only. It doesn't matter where the slot is in relation to TDC. If the top of the hub (12 o'clock) is TDC, and the slot is at 1 o'clock or 5, 6, 7, 11:45...... it doesn't matter. It is the same load. Crankshaft load transfers to the hub in varying speed and force yes, but it would wear the hub the same no matter where you bolt it in relation to TDC.

I think what he was inferring is if he would get less wear by having the slot in line with the crankshaft throw or 90* to the throw.

I was thinking about this today ( yes, machinists have these same thoughts too ) and I came to the conclusion that a tighter fit ( being less worn ) on the spirol pin would have a greater impact than it's placement on rotation.

I think if you line it up with the curvature of the earth and the phases of the moon it may ok.

That probably affects it as much....... :biggrin2::biggrin2:

:ExtremeFunny::LMAO1:

Yes Jeff, that's right. Your idea on being tighter tolerance could in fact result in less slop, but if the slop is exaggerated by the relationship to combustion position of the crank it may make sens that there is a more or less favorable position. However it could be that it really doesn't matter, or that the design was inferior considering they eliminated it and went to a rubber disc in later models.

darkminion; Funny, but probably wrong.


The images show the crank in position of piston being at TDC. Image with slot just past 12:00 is just advance of TDC, and the second is no movement of crank, but hub rotated one bolt hole.

Either way the combustion forces would be applied through the hub and that's probably why it still wears pretty badly. However I thought it would be small minded to assume I have all the answers,or that it has to be one way.

once you have it mounted and running,see if there is a difference in vibration at its present location,and at 180*

Rotational forces
 

The flywheel is there to smooth out the replicating forces and convert to balanced rotational force. The degree of offset will not change the rotational force. The reason that they wear is alignment and tolerance fit. If you check I think that you fined lateral wear along the slot before you see rotational wear.

The location of the roll pin lip will have a BIG influence of wear. install the roll pin so that is 90 degrees to the sidewalls of the slot. If it stays there in that location and does not rotate it self that about as good as it gets. :bigthink:

The front pin is solid, not a coiled roll pin.