23D Ditributor

[Vanden Perre]

Can someone tell me what is typically the gap between the extremity of the rotor and the four things (electrodes? don't know how to call them) in the distributor cap.
In other words how critical can be some radial play on the distributor shaft?
Thanks.
Olivier

[b-havers]

I can't give you the exact measure, but it should be pretty tight to let the spark jump from the rotor to the leads...
Too big gap will reduce the efficiency (?) of the spark, and might prevent the car from starting.

[gerrym]

Gap is quoted as 0.35 to 0.40 (mm) but if my memory serves me correctly, the correct way to gap the points is with a dwell meter. In this case spec is 60 deg +/-3.
Regards
Gerry

[billwill]

Gap is quoted as 0.35 to 0.40 (mm) but if my memory serves me correctly, the correct way to gap the points is with a dwell meter. In this case spec is 60 deg +/-3.
Regards
Gerry

He wasn't asking about the points, he was asking about the high tension gap.

Dunno how you could measure or adjust that though.

[twincamman]

I think he wants to know about distributor rotor shaft bearing wear ----ed

[CBUEB1771]

I think he wants to know about distributor rotor shaft bearing wear ----ed

Other interesting situations can arise. I got an out-of-spec rotor once. It looked fine but actually interfered with the distributor posts (negative clearance). It was very exciting on startup to have the distributor cap bouncing around on top of the housing.

[Vanden Perre]

Thanks for your answers. Indeed he was not asking about the points but about the gap between the rotor and the four electrodes inside de cap .
The problem is: the engine is misfiring like hell and I noticed that one electrode is badly damaged (material missing), another one is slightly damaged and two are OK. I can changed them but before that I want to make sure I get rid of the cause of these damages. When I take the rotor between two fingers I can feel some play. It's difficult to say how much but I would guess max 0.5 mm. (But I may be wrong in one direction or the other). The thing I want to know is how much is a normal play in the shaft of the distributor but of course without any measure it is difficult to discuss on the forum. I may try to borrow a dial gauge and a magnetic base and see if I can estimate the deviation.

Olivier

[gerrym]

Olivier, thanks for clarifications and input from all.

The "spec" I quoted for the points, especially the dwell, is important for accurate ignition, especially at higher revs. With a worn distributor, the dwell will not be accurate.

A good spec to aim for is 0.002" total clearance: 0.0005" would be ideal.

The clearance between the ignition rotor cap and terminals is not set to a specification, but controlled by the manufacturing tolerance of the various components: it is more important in any case to get the low tension side correct, ie consistent dwell. By the sound of your symptoms your distributor needs overhaul or replacement.
Try these guys if you want to have a crack yourself (assuming tools and expertise)http://www.distributordoctor.com/distributor_bushes.htm
background reading http://www.custompistols.com/cars/artic ... ushing.htm

regards

[Tonyw]

Folk's,

If you connect up a dwell meter and rev the engine the dwell should remain constant, if it varies them you almost certainly have worn distributor shaft bushes or a worn shaft, how much is a worry?? not really sure but these distributors are not precision high quality items so some dwell variation will be seen. The dwell is far more important on 6 and 8 cylinder as as you have less degree's for error.

A dwell reading that changes obviously changes the timing for those cylinders that are affected. distrubutors are simple devices and should not cost a lot to repair.

The air gap between the rotor and the distributor cap is not as critical as you might think, remember you have something in excess of 20,000 volts jumping accross it.

Hope this is of some use.

Tony W