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Massey 1655 Points


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#1 Avalontractor OFFLINE  

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Posted November 19, 2013 - 12:12 PM

Hello Everyone, I'm replacing the points and condenser on an Onan twin (BF-MS 3221E) that's in our 1655.

 

Please take a look at the picture of the points box here. Is it normal for the "collar" that the plunger slides in to be slanted like this. The plunger is a flat 90 deg. on both ends, you'd think the ends would have a slant to match the slant of the collar, yes/no ?

 

While the collar looks to have been manufactured this way and the hole inside isn't elongated, it's still true, the slant does not look right to me. In the manual the plunger appears to be straight, but it's hard to tell from the illustration.

 

Thanks in advance.SAM_2294.JPG


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#2 olcowhand OFFLINE  

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Posted November 19, 2013 - 12:30 PM

It should be straight.


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#3 Avalontractor OFFLINE  

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Posted November 19, 2013 - 01:03 PM

It should be straight.

That's certainly what I thought. I'm not sure how long the collar has been like this or how it got like it in the first place. Have only owned the machine for a few months. The hole in the engine that accepts the collar appears to be in fine shape and the plunger itself isn't bent. The engine actually runs with the plunger like this. I was replacing the points and condenser as I suspect both are in need of replacement. Do you think it would do any harm to just leave it as found and but in the new parts, or is there any chance I can realign the collar.


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#4 bhts OFFLINE  

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Posted November 19, 2013 - 01:10 PM

Noting to worry about. I just took a onan apart and it is slanted just like yours.


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#5 olcowhand OFFLINE  

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Posted November 19, 2013 - 02:22 PM

I wouldn't try to straighten it up, as the aluminum points case is liable to break.  It's just fatigued over time, and I've seen them slanted like this. I'd leave it alone myself.


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#6 Avalontractor OFFLINE  

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Posted November 19, 2013 - 07:44 PM

Noting to worry about. I just took a onan apart and it is slanted just like yours.

Appreciate the reply bhts. Good to hear it's probably not unusual.



#7 Avalontractor OFFLINE  

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Posted November 19, 2013 - 08:13 PM

I wouldn't try to straighten it up, as the aluminum points case is liable to break.  It's just fatigued over time, and I've seen them slanted like this. I'd leave it alone myself.

Thanks Again olcowhand. As i said to "bhts", glad to hear it does not seem to indicate serious trouble. Still hard to figure the reason for it either being a design matter or a wear and tear issue. If it's intentional you'd think the hole in the engine would be machined to match. It's not. Also, the plunger is square on both ends so to me that means the contact with the lobe would place the edge of the plunger "butt" against the lobe and effect the function and longevity of both surfaces. On the other hand, the tolerance between the plunger and collar is very close so I can't imagine how the collar would be able to shift from the tiny amount of lateral force applied by the lobe when it engages the rod. Meaning  I'm back to it being part of the design. Other clues, perhaps, to this being the way it's supposed to be; the inside bottom of the box, where the collar becomes part of the case shows no deflection at all. If the collar was forced out of the "as molded" position I'd expect to see evidence of that there. Also, the plunging action is very smooth, no binding and no damage to the surface of the plunger sides can be seen. Finally,the contact point where the top of the plunger meets the points is consistent. If this point had changed over time (I'm pretty sure the same points have been in use for 15 years), I'd see an elongated contact patch(or two distinct ones) on the points. The mark is quite condensed.

 

My worry, if it is related to wear/fatigue is that when I put in the new points the .025 gap will not be correct as the plunger travel will be shorter.

 

I'll let you know how it works out. Thanks Again for the help. 


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