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distributor diagnosis

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Does this distributer look bad, the shaft below the rotor( not sure what it is called) looks pretty chewed up in sections,

iit is a 69' 521 with j15 engine, im having some rough running backfire issues, and was going to install new points and condenser

but wondering if the condition of that shaft means i should replace the whole thing, Have been able to find dizz for the j13 and j16, are either of these the same as this one on j15? 

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Look ok. The shiny areas are lobes like on a camshaft. The points wear block is pushed up to go over these and the points open. The dark areas are just grease where it doesn't rub.


Gap new (or old) points 0.018" to 0.022" Timing is 8 degrees BTDC



Back fire?? Out the exhaust???

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Hard to say from that photo. If you wipe the cam down we could maybe tell. If that is rust it may wear the points rubbing block quickly. In any case if the dwell meter is at 49-52 degrees it is good



Wiggle the shaft side to side. Any play in it will wreak havoc with the spark.

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just checked that is just grease, fairly clean when removed no wiggle side to side little up down, truck had been sitting long time when i found it, ive done a bunch of work but have not yet addressed the distributor, i will check gap and am wondering if there is any general maintenance even if it is not the cause of my rough running issues

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Checking the gap is only accurate with new points, because as they run a crater and peak naturally occur with the contact points. For this reason use a dwell meter.


Maintenance calls for new points & condenser every 12 months/20k kilometers.


Some old timers file the points, then re-check them with a matchbook cover (which are about .020 inch thick).

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