1800: bosch distributor 0231153003

[grant 1800]

Hi,
My b18 motor has been back firing on a slow start after sitting for 10 or 15 minutes after driving 500 feet or so. I have also experenced ocassional run on when turning the motor off. I pulled off the distributor cap and gave the rotor a light twist to see if the mechanical advance was hanging up. To my suprise the rotor turned 360' with very little effort. This i asume is not suppose to happen. What is wrong with the distributor. Now I am not even sure it is pointing the right direction.

[Volvorama]

The rotor arm should have a raised portion when you remove it and look underneath. It fits in the slot on the distributor shaft. Possible faults you have are:
A - damaged or incorrect rotor arm
B - damaged distributor
C - damaged drive from camshaft / oil pump

I'd guess A as B and C would have other consequences. Does the car not run at all now?

[grant 1800]

Originally Posted by Volvorama

The rotor arm should have a raised portion when you remove it and look underneath. It fits in the slot on the distributor shaft. Possible faults you have are:
A - damaged or incorrect rotor arm
B - damaged distributor
C - damaged drive from camshaft / oil pump

I'd guess A as B and C would have other consequences. Does the car not run at all now?

A-I know the rotor is correct. The car has been running on that rotor for at least 600 miles.
B-The points, weights, and springs turn with the rotor. Can these parts come loose and turn without the drive.
C- The distributor was reinstalled 600 miles ago after a complete engine rebuild by phil singer. The drive looked good at that time.
I have not tried to start the engine because I am not positive the rotor is positioned exactly right.

[Volvorama]

Is the rotor turning around on the shaft of the distributor or is the shaft itself able to turn more than a few degrees?
If the shaft is free to turn then something nasty has happened.
If the springs, points and base rotate with the rotor that's really wierd....

[Derek UK]

It's still possible that the rotor is the wrong one. Some will appear to fit but the drive peg doesn't hold in tight. Some are too short or are a loose fit. Sometimes possible to lift the rotor just a fraction and it will turn if it's the wrong one. The body of the rotor should be quite long and be a smooth tight fit with the drive peg fitting snugly. The width of the brass piece does give a bit of lee way. I'd try a known good one first, possibly a new one from one of the usual suspects.
Congrats on your Singher engine, should be a nice one.

[grant 1800]

Update:
I pulled the distributor and found that the dogs on the distributor were barely engaging the drive gear. If you twisted the rotor the dogs would slip out of the drive gear. I was able to lower the distributor 1/8" into the clamp housing. Now the dogs fit down into the drive gear and the distributor shaft cannot slip out of the drive gear. Tommorrow I will finish putting everything back together and start it up. Thanks for your help

[CLIVERALLY]

Yep. Had this with a customers Jaguar. He had removed the dizzy but did not have it seated correctly ...still an easy job for once