Engine: 2.1 Carb B21A: PCV System with aftermarket Webers Help please.

[spease1984]

classicswede I have the option of both but what is the difference if I connect the 123 Distributor to the Weber Carb instead of the manifold? I thought by connecting it to the manifold I was retarding the timing?

If the distributor has to be connected to the manifold then I will connect the crankcase breathing to the carburettor then??

Once all setup and it passes it's MOT then I will play about with the jets and finally have a rolling road session.

[Clan]

Originally Posted by spease1984

classicswede I have the option of both but what is the difference if I connect the 123 Distributor to the Weber Carb instead of the manifold? I thought by connecting it to the manifold I was retarding the timing?

If the distributor has to be connected to the manifold then I will connect the crankcase breathing to the carburettor then??

Once all setup and it passes it's MOT then I will play about with the jets and finally have a rolling road session.

The 123 is a computerised ignition advance/retard timing unit which needs data input to match your ignition curve , the difference is that when you connect the Vac pipe to the manifold it senses the vacuum there all the time in all throttle position so is a good indication of the load on the engine .. IF you connect the pipe to the nipple on the carb , yes it will work in the same way EXCEPT when the throttle is shut there is NO vacuum going to the ignition unit when it should be near max vacuum reading to sense load properly .... so it must go direct to the manifold and preferable somewhere in the middle of the 4 branches to get a smooth pressure reading , if you put it in just one port , the reading is going to jump around all over the place with each pulse of air from that port .

[classicswede]

That basically explains it.

The original distributor is a mechanical advance system

The 123tune has a built in MAP sensor for the ignition table. Connecting to the carb would tell the 123 that you are on full throttle when the carb is closed


With your single carb just connect to a common area of the manifold rather than in a runner