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Excessive rotor rotation?


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I have a DA-6 and it has the distributor mount on top of engine. I noticed excessive play in the rotor rotation. 

The distributor rod at the top of engine block has an offset slot. The rotation at the top is 20 degrees + or -. 

It may be the slot in the rod at the top and bottom is oversized from ware. Should the rod be replaced?  

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I am asking for information because I am rebuilding my engine.

Referring to attached picture note possible places that could have wear: 1) lose pin connection at cam drive gear, 2) worn slot at cam gear, and 3) worn slot at the distributor. If this is a problem can these be repaired or replaced.

 

10A4A414-F01B-4C4A-9E17-2859CD0EF2D8.thumb.jpeg.f69acef9544e9c717a598a593fbe7072.jpeg 

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I am not familiar with this distributor, but what is excessive?

Is there a mechanical advance that might be confusing you?

The places (slots at least) that you are pointing to don't look like there would be any noticeable play unless those tangs are way worn, and that would be obvious.

What happens when you grab that gear and twist the rotor?

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On 4/28/2019 at 11:12 AM, stakeside said:

I noticed excessive play in the rotor rotation.

I am afraid I don't know what you mean.

 

If the distributor is in place, are you saying you can rotate the rotor back and forth quite a bit?

 

I found my timing wandering around. The problem was the distributor mounting in the block. It was loose. Movement of the entire distributor resulted in variation in timing. It's not like that now!

 

Remember that the rotor is always driven and doesn't ever get to "coast" or slow down.

 

The distributor rotor will have some rotation possible by hand because of the springs etc. in the mechanical advance mechanism under the top plate in the distributor. Is that all in good condition?

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3 hours ago, Spinneyhill said:

The distributor rotor will have some rotation possible by hand because of the springs etc. in the mechanical advance mechanism under the top plate in the distributor. Is that all in good condition?

 

Spinney, he says that it has a manual spark advance.

I am thinking like you that there is a centrifugal advance as well.

 

 

6 hours ago, JACK M said:

What happens when you grab that gear and twist the rotor?

Try this. It will eliminate all the parts that you show and possibly confirm a mechanical advance

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I am not familiar with this engine but it appears to me that the shaft with the slotted ends (marked 2 and 3) probably drives the oil pump and therefore would have no bearing on any slop/movement in the rotor.  Have you checked the distributor shaft/bushes for wear ?  If not this is where I would be looking.

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Got me stumped.

I cant figure 15 degrees of slop in that mechanism unless there is a lot of play between the cam and distributor gears.

Or as Stude suggests, loose bushings in the dist. itself.

Heres an idea, put the distributor in without the oil pump shaft and see what the rotor does. If as you say the rotor and gear are solid to each other and you still get the movement it has to be either the gears or the bushings. But you should be able to tell if the dist shaft is sloppy in the housing due to bad bushings.

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3 hours ago, JACK M said:

Got me stumped.

I cant figure 15 degrees of slop in that mechanism unless there is a lot of play between the cam and distributor gears.

 

 

Yes this could account for some of it and replacing the distributor drive gear could help, however, unless you want to replace the cam shaft not much else can be done in this area.

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Just my 2¢ as soon as the engine starts all of the slack closes up and is not a problem. Some what like the old steam trains as they. Started up each coupling would click as the slack was pulled up afterward  there would not have any slack. Just set the timing per the manual and let it rest.

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Thanks for all your input AACA folks.

I am trying to resurrect a DA6 and have been trouble shooting it. I have got it to fire but it will not hold idle. Guess next item is the carter BB1 carb adjustments. 

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