123 R-V-IE Distributor vacuum question, Stock D-Jet 1.7L in '72 914-4 Options

[Stev914]

Greetings 914 Worlders:

I'm happy to be asking this question when my car is running GREAT. I'm just really trying to understand how the engine works, and I am puzzled by this.

Q. How does the 123 R-V-IE work with one vacuum line when the stock distributor has two (advance & retard)?

Longer story:

My local mechanic recently replaced my stock distributor with the 123 R-V-IE and adjusted the settings. The engine is mostly stock and has the original D-Jet. It's driving great. I note that there is a single vacuum line into the distributor (I assume this is vacuum advance). The other green hose (I'm assuming this is the retard) is fitted with a plug. Car runs great.

I have my old distributor, which has the advance and retard connections, exactly like you see in this video tour by George Hussey:

https://youtu.be/ioJ1yYU5MrM?si=sEvnLv0Z_cDd_h1s&t=220

Again, the vacuum retard hose in my car is just fitted with a plug now. I am assuming that's not a problem, but I am still wondering how the 123 R-V-IE is meant to integrate into the vacuum system. Here's a great illustration I found here on this forum posted by Jeff Bowlsby:



Sorry for the very newbie question.

Steve
1972 914-4

[emerygt350]

I actually like the non-bluetooth. Some of the best info is going to be on this forum but the Haynes and clymer manuals are good to have on hand. Neither will give a whole lot on d-jet though. For that you need to hit pbanders https://members.rennlist.com/pbanders/ and the other d-jet forums. That is probably more than you need right now though. The book by Tim Wilson (on Amazon) is essential. That tells you all you need to understand the type 4.

You can unplug the hose without any issue. Just make sure the port/s on the throttle body are capped. Some have both the retard and advance others only the retard. Just depends on the year. I put a cap on my 123 vacuum port to keep it clean.

You need to verify which ports you have on your tb and you need to verify which program your 123 is using. Then you can know whether you should hook it up or not. I am not too familiar with the 1.7 TB. The front and rear ports I mentioned are specific to the 2.0 TB. The 1.7 was stopped for the 74 year so it might have always had both ports.