2 replies to this topic

[Syma]

So I am restoring a set of twin HS2 carbs to replace my single HS4 carb. I am almost done and they are looking amazing but I just noticed that there is no vacuum port to go to my vac advanced distributor. Looking for opinions on my options.

1. use a carb spacer with a port on it

2. I have a vac port with threaded end so I could drill and tap the plug on the manifold

3. I could find the proper vac port and install it on the carb. I found instructions online for location and drill size plus I could confirm the measurements off of a friends carb.

4. do nothing and cap the vac port on my distributor. (not sure if this will cause and issue)

 

Thanks in advance 

[timmy850]

The standard HS2 vacuum advance port is on the outside of the throttle blade, so at idle you get no vacuum = no advance. If you take the vacuum from the manifold side of the throttle blade you get full advance at idle (which is how some cars do it). 

 

The early Cooper setup had one carb with the vacuum port to provide advance. Later Cooper S had no vacuum advance at all. If you don't use the advance you don't need to block off the port to the distributor, it'll just stay at the base setting

[Syma]

The standard HS2 vacuum advance port is on the outside of the throttle blade, so at idle you get no vacuum = no advance. If you take the vacuum from the manifold side of the throttle blade you get full advance at idle (which is how some cars do it). 

 

The early Cooper setup had one carb with the vacuum port to provide advance. Later Cooper S had no vacuum advance at all. If you don't use the advance you don't need to block off the port to the distributor, it'll just stay at the base setting

Since my carbs don't have the port on the side maybe for now i will run without vacuum while I look more into drilling and adding one to the proper location. http://www.spridgetg...com/TA0139.html