Headers installed, no EGR Valve, how do route vacuum hoses

[Mswilkes81]

I just bought my second classic Bimmer after 20 years. I picked up a 1978 e21. The vehicle has headers already installed and i noticed it does not have an EGR valve. how would the vacuum lines need to be routed/plugged in order to make this work.

[epmedia]

I just bought my second classic Bimmer after 20 years. I picked up a 1978 e21. The vehicle has headers already installed and i noticed it does not have an EGR valve. how would the vacuum lines need to be routed/plugged in order to make this work.

Hi and welcome to the forums.

Leave #1 distributor (vacuum retard, inboard port) connected as shown with the timing valve #5 and throttle body vacuum. *Important: this inboard port on the canister connects to the outboard port of the timing valve. Test this timing valve - it should snap open after several seconds of warm-up to allow vacuum to pass through it and the engine idle speed should decrease a bit.

Leave #9 vacuum valve connected as shown.

Not shown in the diagram is 4th gear vacuum advance components - Keep these. Distributor vacuum canister outer/lower-port connects to the top-port of an electric valve on the firewall. The bottom port of the electric valve connects to the throttle body where the #4 thermo valve would connect. You don't need to use the #4 thermo valve without egr, just bypass it.

Make sure the vacuum canister on the distributor holds a vacuum on both ports - if there's leakage, it's a vacuum leak and the vac advance/retard functions won't work. Plug all the unused vacuum ports.
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Alternatively:
You can experiment without vacuum retard (cooler exhaust temp at idle without vac retard). You can experiment with vacuum advance connected directly to the throttle body (instead of only 4th gear). Leave #9 connected unless you experiment removal of #8 and #9 (I've not tried this experiment).