Rotor arm won't come off

[ashaughnessy]

I can't get the rotor arm off my distributor. Supersprint with the bosch (I believe) leaded distributor with the "side-exit" cap. It has lucas electronic ignition. The rotor arm is the type with the four metal "skirts". A good pull won't pull it off. Is it held on by something or do I just need to pull harder? This is the first time I've tried to remove it in 11 years ownership!

Anthony

[Tony Martyr]

I don't know your engine but the rotor arm on my k series was held on by a screw going radially into the flat of the stub shaft

[oilyhands]

Mostly rotor-arms just push on although they can sometimes be very stubborn, the K series is unusual in that it is bolted onto the spigot, BMW rotor arms are alos bolted on. I think your one is just a bit tight, some have the slotted drum attrached to the rotor arm, with others the rotor arm and drum are separate, the ones with the drum attached are always *ing* tight since they rely on the rotor arms alignment to spin accurately.

 

Oily

[Paul Turner]

My guess is that your Bosch dizzi has suffered the same problem as mine did in the early 90's i.e. the rotor arm can move slightly on the shaft (it seems to get worse in time) and since the chopper is part of the rotor arm there is a timing variance (mine was approx + or - 4 degrees, enough to cause either severe pinking or zero performance). The cure was replace the rotor arm at approx. 2000 mile intervals and hope or replace with a Lumenition kit, guess what I did. There also seems to be a cure that I did not consider.

[Roger King]

This ignition system is beset with rotor arm problems. I can't believe you've run that long without a failure!

 

The rotor comes loose on the shaft due to wear of the lug, the metal skirt comes loose from the plastic rotor too. Both cause the ignition timing to go walkies.

 

We have seen several where the owner has glued the whole assembly together to get round the problem. Could it be that your rotor is glued onto the dizzy shaft?

 

If you've had the car from new, you'd know the answer, if not, you'll have to find out.