Distributor spindle tolerances; original and accuspark comparison

[JonE]

I've just compared my new accuspark distributor unit and a good DK4A, and if I grasp the central spindle, I can't move the Lucas - it rotates nicely but there is obviously an extremely good fit in the bearings. 

There is a discernable sideways movement in the NEW unit. Its good and loose, but if I grasp it, I can make it move 1/2mm or so from its axis, enough for it to make a slight noise. i.e. its just generally "a bit more loose". 

Is that a normal tolerance for this sort of unit? i.e. what do others' new units do please?

[AustinWood]

For distributors with points movement in the spindle is bad news as it affects the trigger point and the dwell.
However with the magnet sensor I doubt if it makes any difference to the performance.

[bob46320]

You don't mean that do you ? 0.5mm slop - is that the whole distributer or the spindle inside the distributer. If its inside, I would have thought that it would alter the timing erratically when running. I suppose there is a big difference between a Contact breaker unit and an opto electronic unit, but it still seems a lot.

[Ian Williams]

The play sounds ominous Jon, if the advance mechanism in the Accuspark units is also poor quality and wears quickly you will soon be back to square one. I think the chief advantage of these new units is probably the fact that the advance curve is controlled by unworn parts rather than the fact that they are electronic. A worn Lucas DK4 scatters the timing all over the place, however as I have mentioned in the past, this can be rectified.

[JonE]

For distributors with points movement in the spindle is bad news as it affects the trigger point and the dwell.
However with the magnet sensor I doubt if it makes any difference to the performance.

That's why I was a bit wary of posting... but I'd be interested in others' views with new units. 
It is difficult to quantify the movement, but it's enough to give a v. slight 'waggle' when grasping the bit that the rotor arm attaches to, inside the distributor, yes... or grasping the cog at the bottom of the unit and moving it sideways with the distributor in your hand.

[Ruairidh Dunford]

There does appear to be play in the new units but it certainly does not affect performance, in my experience.

These units are well tested with several fitted now covering in excess of 3000 miles each. If problems occur it will be well reported but I would suggest your unit sounds very similar to the ones I have here and would suggest therefore that it will be fine Jon.

[Zetomagneto]

I would have said .5 mm/ .020” is excessive, I wouldn’t be happy with a new unit with that much play.
Jon can you check the play with a dial gauge at a right angle to the spindle.

[jansens]

I just went and checked mine. It's new, never fitted. No sideways play I could see. About .3mm up and down. I don't have an original to compare against. I do have a converted VW unit (also unused) and that was the same, no side to side play, just a little lengthwise.

I don't know about A7 dizzys yet but I do know when I rebuilt my MGB I had the distributor refurbished but the timing was still a little variable with the mechanical points. I changed to electronic contactless points (Pertronix from memory) and the timing became rock solid. 

Simon

[Mike Costigan]

I, too, have a new, unfitted, unit, and it matches Simon's: zero sideways movement, slight vertical movement.

[bystander]

Is there a good reason for play like this in a new unit, or is it just poor quality control/ sloppy manufacturing practice? No implied criticism - just curious to know.