123 Dizy

[guitarman]

I have recently had my 164 tuned and it runs far better. The 164 distributor has both advance and retard- something I'd not seen before. I think it is to satisfy the American market, however whilst reducing emissions it seems to use more fuel! A whizz my friend showed me ( which he has used on several of the American cars he's owned) is to remove the retard pipe from the carbs and permanently block it, then to tune up in the normal manner. Power is up and fuel consumption has dropped noticeably! I don't entirely understand the physics of what he's done- but hey it works!

[guitarman]

ps- There is a 164 dizzy on ebay right now!

[arcturus]

I'm holding on to my old dizy just in case I ever have a problem with the 123. Electronics are tempermental!

[swedishandgerman]

Originally Posted by guitarman

I have recently had my 164 tuned and it runs far better. The 164 distributor has both advance and retard- something I'd not seen before. I think it is to satisfy the American market, however whilst reducing emissions it seems to use more fuel! A whizz my friend showed me ( which he has used on several of the American cars he's owned) is to remove the retard pipe from the carbs and permanently block it, then to tune up in the normal manner. Power is up and fuel consumption has dropped noticeably! I don't entirely understand the physics of what he's done- but hey it works!

I would disconnect the retard pipe and permanently block it too

Basically, the purpose of the vacuum unit is to alter the timing of the spark in relation to how varying mixture ignites. At weak mixture, such as at vacuum at low rpm and small throttle openings, the spark timing needs to be advanced. As such, the vacuum advance unit advances the spark timing. This results in better response from low rpm and increased fuel economy

To burn strong fuel mixture, ignition retard is advantageous. As such, some cars were fitted with vacuum units that retard the timing under heavy vacuum such as engine braking, changing gear quickly and going downhill. These vacuum units do nothing for performance and power, but improve exhaust emissions slightly

From experience, vacuum retard units play up and can cause bad running and well increase fuel consumption

They are fitted to twin carb B20's (078 distributors). These types are frequently seen to have been disconnected and the vacuum port bunged. They do nothing to the way the engine performs, but frequently decrease efficiency. Get rid, in my opinion! The mechanical advance mechanism in the distributors provide good advance for good performance

[woolfie1948]

Is it
Retard pipe coming from carbs?
Advance pipe coming from manifold?

Are you saying you would disconect and plug both (as when setting the timing with a light) and leave both plugged permanently, or just one?

To answer an earlier question I have used the pencil rubbing method to get the number embossed into the distributor body to get 231 142 001.

[swedishandgerman]

Originally Posted by woolfie1948

Is it
Retard pipe coming from carbs?
Advance pipe coming from manifold?

Are you saying you would disconect and plug both (as when setting the timing with a light) and leave both plugged permanently, or just one?

To answer an earlier question I have used the pencil rubbing method to get the number embossed into the distributor body to get 231 142 001.

I think the advance pipe comes from the carbs and the retard comes from the manifold. I'm not 100% certain on that though

There are 2 ways to check. I would say that the advance pipe is the one that sticks out the front of the vac unit and the retard is the one that sticks out the back

Otherwise, with the engine running, you could suck on the pipe. If the engine speed increases,it is the advance. If it is the retard, the engine speed will drop

Just disconnect the retard one and see if it makes any difference on the way it drives. You need to keep the advance pipe connected as that improves efficiency and performance

How are you getting on with the shaft? Once free, you should notice that you should be able to grab the rotor and twist it a few degrees. There should be a good amount of resistance and it should spring back with a definite sort of "clink". If you are unable to do that satisfacorily, let me know because I'm reasonably confident that I can get hold of an 001 distributor that I could recondition for you - thank you so much for getting the Bosch number for me

[woolfie1948]

Just been out and put the timing light on with both pipes plugged.
When revved hard the timing marks did not move much so I think the earlier suggestion that the mechanical advance or retard has jammed is the answer. Confirmed by my attempt to turn the rotor by hand - it moves very little.
It looks like my choice is now to bid on the ebay one or have mine reconditioned. I tried thin oil but cannot get it to turn so maybe something has broken inside.
Many thanks to all who have responded - I would still be interested to get an answer to my question about one or both pipes to be plugged and which one is which.

[woolfie1948]

Thanks swedishandgerman
We seem to be crossing with our responses
Would you like to call me? 07831388189