Harsh sound with Mark V

[olivier06]

Hello,
I am new here on the forum.
I have a Mark V and it started to make some strange noise and it is hard to change the speed. It always made noise (and a lot of vibrations, which I don't know if it's normal), but now it sounds like if there was gravel in the motor. I read a few posts in this forum (great forum by the way) and I now have a few ideas of what it might be, but I would like to have the opinions of more experienced users.

First, the motor in itself runs smoothly. It's almost silent when I run it after taking the belt away.
From what I read, it might be:
- Lack of lubrication. I didn't know I had to lubricate every 10 hours. Although I didn't use it for much longer, I might have reached 12 hours.
- The belts that are too old. Maybe both belts, but mainly the one from the floating sheave to the control sheave. I don't know when it was changed for the last time.
- The quadrant has to be changed. The teeth are a bit worn out, but I'm not sure if it needs replacement. The thin metal sheet in contact with the control sheave is also a little bit worn out.
- The control sheave is a bit worn close to the axle (where the belt would sit at high speed). But the noise is not only at high speed. Also, the metal in contact with the quadrant looks like it got very hot.
- Finally, the screw hole to hold the speed control at 2 o'clock is broken, so the speed control is held at that place with a washer. Maybe that allows some movement.

What do you think about it?
Thanks

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[everettdavis]

What does the button bearing in the other end of the control sheave look like? what does the other sheave it mates with look like? Obviously replacement of the control sheave which will get you the button bearing assembly staked into it is in order. I’m wondering if there wasn’t something that got loose and got between the sheaves and ground into them by the belt at this point.

I have seen far worse quadrant wear and the two ears holding it in place aren’t wedged apart like most damaged quadrants.

Take a look in my post above yours and snag Bill Mayo’s Headstock Improvement Kit document. It’s excellent for speed control service.

Everett

[olivier06]

What is the button bearing?
I'm also not sure of what part you mean by " the two ears holding" the quadrant.
The other sheave looks good.

[everettdavis]

Read Bill Mayo Document. The ears hold the quadrant in place. That’s the pork chop shaped arm with teeth in the speed control dial.

Hers is the button bearing

Everett

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[wa2crk]

Is there a bearing on the opposite end of the control sheave?
The sheave looks as though it opened too far and the ends of the interlocking fingers were clashing against each other instead of meshing properly hence the noise and the damage.
If the motor runs smooth and quiet with the belt removed I would not suspect motor bearings at this time.
I would recommend replacing the sheave and the associated sheave with new ones and checking that the bearing and it's little clip is still on the sheave. The quadrant teeth in my opinion are worn too much. The teeth can be filed but don't take off too much.
As for the broken casting you can accept the damage by re-installing the quadrant assembly with the washer on the rear of the casting opening as it is in your picture but reinforce it by installing a nut on the rear of assembly to hold the washer. This can be done by reaching in through the inspection hole on the rear of the headstock and thread the nut on. I used a piece of aquarium tubing to hold the nut to get it started and snug it up with a socket wrench.
I believe that it will hold OK.
Bill V

[wa2crk]

It looks like that the remains of the bearing is still in the idler sheave shaft. The hole I see is too small and the inner race of the bearing is missing the button. (it is the part called "button" in Everett's picture.) I would NOT use a new control sheave with an old one. The old one is worn but why mix an old part with a new one. Don't invite problems.
All of the problems may be traced back to the failure of that bearing.
By the way, Welcome to the madness!!!
Bill V

[olivier06]

Ok so the ears are the two metal sheats on both sides of the quadrant/porkchop, right?
thanks everettdavis for the Bill Mayo Document.

wa2crk - I forgot to say but there is also a nut behind the washer. So you think I should really change the shieves?
The button bearing and the clip are still on the control shieve, but I'm not sure of their condition. The clip moves from side to side, is that normal? And as I said in my first post the metal of the control shieve axle near the button bearing seems to have got hot. It doesn't show well on the photo but there are purple lines on the metal.

[wa2crk]

It more than likely did get hot from the bearing not getting enough lubrication. A new sheave should come with a new bearing and clip. What I see in your pic is the remains of the loop and the roll spring is missing. Check the picture that Everett posted. The loop has to go over the spring finger on the quadrant assembly
Bill V

[olivier06]

I'm not sure which spring you're talking about. There is a small coil on the loop of the button bearing. Is that what you mean?
Here is a picture of the assembly

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What looks like the button bearing on the control sheave is not exactly like the image Everett posted. The button is less round, and it looks like the bearing is inside the metal "tube" of the control sheave. Is it just an older/newer version of the button bearing?

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[olivier06]

I checked the possible cause of the worn interlocking fingers of the control sheave. As there is a groove to hold it in place, it is impossible that wear was made by clashing against the other sheave. I checked closely and the fingers cannot touch one another.

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I also took a picture of the belt. I guess it is pretty worn out, but I never saw a new one to compare.

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