Rotor Arms

[Leo]

Recently I experienced sudden unexplained loss of ignition. The car just cut out at a junction and refused to fire up. There was fuel coming out of the pump and a spark across the points but it just would not start. Then about 20 minutes later the car fired up as if nothing was wrong.

I decided to replace all the ignition components, Coil, Leads, Distributor Cap, Points, Condenser, Rotor Arm and Plugs.
Although my suspicions were that the Rotor Arm was the cause.
These components were ordered from a Major Minor Supplier advertising in Minor Matters and arrived very rapidly and at a very reasonable price.

Now the problems, the Rotor Arm supplied will just not fit on to the distributor cam, I think you would have to hit it with a hammer to make it fit.
I had another Rotor Arm that I had bought about a year ago for my previous Minor from a different specialist Minor supplier and that would not fit because the lug on the inside was to big.
Both these Rotor Arms and the one on the car look to be the same make.

Is there a problem with Rotor Arms for Minors?
They are so cheap it is hardly worth complaining but in my mind it does give the supplier a bad reputation. I would much prefer to pay more for these components with the quality assured.

I also found that the Distributor Cap supplied was very difficult to fit and have decided to obtain a better quality one from another source.

In desperation I have ordered a Rotor Arm from the Distributor Doctor, I have used his in products on my other classic ( a Rover p4). They are good quality and give no problems.


Leo 1969 Traveller and new to the Club Forum

[Orkney]

have you called the supplier to see what they say ? seems odd that the ca is a bad fit too - makes you wonder if its a non standard distributor ?
If you stick a photo on here someone will be able to tell you pretty quickly if it doesnt look normal.

[aupickup]

yes first option ring the supplier and see what he says and check the dizzy is correct

[Packedup]

I've heard lots o bad things about the current repro arms for the 25d dizzies. So far I've been OK with mine, but then the car does very low mileages. The arm was a bit of a poor fit though (typical motor factors pattern one, might have been an Intermotor).

If you Google Rarebits4classics they have had 25d arms made to original specs which in theory makes them a far higher quality item than the cheapo ones most places stock.

[dalebrignall]

you might have the later 45d type distributer . i have on mine had the same problems till i did some resarch.the 45d has a flatter dizzy cap than the 25d and the rotor arm os straight rather than curved there is a marked differance

[Leo]

Thank you all for your advice.
I have now found out what is wrong.
The spring inside the pattern rotor arm is not curved and will not allow the rotor arm to slip over the cam without using a lot of force.
I have managed to get hold of a new old stock Unipart Rotor Arm and that fits perfectly. The Unipart one has slight indentations stamped in the spring which allow it to fit without undue force.
When The Distributor Doctor Rotor Arm turns up I will carry it as a trusted spare.
Also delving into my hoard of spares I found a new distributor cap, probably 20 years old but unused. That has gone on the Moggie and I will carry the pattern one as a spare

Leo

[bmcecosse]

Only if the 'pattern' one fits! I would use it - and carry the new-old-stock one as my spare.

[Kevin]

I would still let the supplier know in cae they are not aware of the problem with the parts because if no one tells them they may be none the wiser for some time.