Distributor Advance

[knapmann]

So when I managed to get my engine sort of running I couldnt get it to idle. It would idle high and low and never went back to where it was when I pressed the pedal. It has the correct 007 distributor for a 69S. I suspected maybe the distributor advance was sticking or something but I dont have a timing light to prove it.

I took my distributor out today to see what the advance mechanism felt like and gave it a lot of spray cleaner and lubricant. I cant decide if its ok just from handling it. If you twist the rotor to its full advance stop and simply let go it snaps back like it should, however, if you twist it to full advance and slowly release it gently by hand about 50% of the time it sticks somewhere in between and doesnt fully return unless you give it a helping hand. Intuitively I would think that any amount of sticking is no good.

On this note, are there any reputable UK distributor rebuilders?

[jwhillracer]

As long as the main spindle isn't worn, it could be worth fitting a Classic Retrofit CDI box, locking the advance and programming it through the box. The 2 litre S engine responds really well to accurate ignition timing.

Cheers
JW

[knapmann]

As long as the main spindle isn't worn, it could be worth fitting a Classic Retrofit CDI box, locking the advance and programming it through the box. The 2 litre S engine responds really well to accurate ignition timing.

Cheers
JW

Good info to have, I like options, I will look into it. Would you generally agree that any sticking is bad? Im thinking that as engine revs only drop relatively slowly when you release the throttle its the same as releasing the advance on the rotor slowly by hand, i.e. the sticking im seeing/inducing is likely to be happening in actual use.

Ive read a few people who say the 2.0S needs accurate timing. Ive also read this thread where the seemingly knowledgeable person who rebuilds distributors commercially says that "The 69S distributor. It carries the same curve as a 2.2 but is completely inappropriate for the motor. Too aggressive. A 67S curve would be better." he then goes on to say.... "One model specifically that will benefit is the 69S as it has too much compression and too aggressive of a curve. That one would get a completely custom curve. Something that is not possible with the original dizzy." I dont suppose anyone knows anything more about this... it kind of makes me think it would be good to get something on which I can adjust the advance and try different settings as opposed to rebuilding the original distributor which is obviously not adjustable.

https://www.early911sregistry.org/forum ... stributors

[jwhillracer]

I know with my one, it was worth spending time to get the dwell angle and timing as near spot on as I could. It made a great difference to the torque and drivability of the car. If the advance is sticking, you are likely to be over-advanced in the situations where you have backed off or braked, and then accelerated away again. The new box ought to help the car’s performance as well.

JW

[mycar]

Surely the advance curve, whether correct or not, will have little bearing on how the engine ticks over ? I would say that a timing light would be a good investment at this stage. I always sent my distributors to the States for rebuilding but I know that PRS have a Sun machine and are able to rebuild distributors.

Before you send the distributor away (or buy the excellent 123) tune your car. Adjust the valves, check the fuel delivery is in spec and time the engine correctly.

[PeterK]

Ordinarily yes, but If the dizzie weights, etc are randomly sticking then you may well have too much advance at tick over. Resetting timing at this point without fixing the 'sticking’ will have you chasing your tail


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[knapmann]

Ordinarily yes, but If the dizzie weights, etc are randomly sticking then you may well have too much advance at tick over. Resetting timing at this point without fixing the 'sticking’ will have you chasing your tail


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Exactly what I think I have been doing, chasing my tail. I set the idle think all is well rev it a bit... oh no idle is crap now... reset it again, rev it a bit...

I know i need a timing light really. Ill buy one before I spend any serious money but Im starting to think my distributor is the root of my issues.