I have a vacume advance dizzy.. I also have a 76 TB with no vacume advance port.. but a place for one. I dont quite understand how a vacume advance works, so therefore I dont know what I need to do to get mine to work. I have both "nipples" on the advance mechanism with nothing on them.

I could take some pics.. but I think that will get you guys going..

Any help?

Im totally confused..

The 75 & 76 throttle body has only one vacuum port. The diz may have two. run a hose to the distributor side of the vacuum can, and leave the other open.

The vacuum advance port is located above the throttle plate not below it. At idle (high vacuum) the retard needs to work not the advance! As the throttle opens it pulls a vacuum on the port above so it advances the timing( duh, vacuum advance). At higher rpms the mechanical advance is full in at 3500 rpms, the vacuum advance operates from 1500 to 2500.
Its pretty easy to drill a hole for a piece of steel tube (the right size is IIRC-4mm). Using a drill stop, gauge the depth of the hole and drill it. Then drill a small hole all the way thru, I think this is the smallest drill in a small drill assortment. Tap in the tube and knurl around it to seat it.
I have done this and it does give you alittle more zip at low rpms.


Geoff

What is the difference between the Bosch 005 and 009 distributor? My understanding is that the 009 is needed for carb conversion. Does the 009 have the advance and retard? Which on is this one?

Geoff, I've heard that a 1.7 throttle body is better than the 2.0 of later years. I have a 1.7 that has two vacuum ports. Is this the reason? Are they a direct swap?

My '75 2.0 has two ports on the throttle body. It also came with the CAT, air pump and EGR valve.

Hmmm, I don't know who told you that as the 1.7l (40mm)TB is smaller and for a side draft setup. The 2.0l is 45mm and you can install the advance port with minimal skills...

The 009 is a piece of shit and I don't recommend it for type 4 motors. Use the stock one or a 050 or a Mallory unit. The 009 dizzys curve is not right for these motors.


Geoff <_<