CU vacumm pipes

[dugcati]

Anyone have a pic of the correct, full vac pipe layout for a CU? The only image I can see in the wiki has pipes missing from the air box

thanks

Doug

[dazwatson]

Can't get to my van until tomorrow, if no replies I will take a picture & post

Daz

[Footprint]

Not a picture, but if it helps:

Vacuum hose on left carb goes to right hand vacuum connection on distributor, (the upward pointing stub on the cone shaped side). Connection from left hand connector on airbox, (via tee piece to balance pipe from behind airbox), goes to left hand connection on distributor, (sideways pointing stub on the flat side).

Vacuum connector on right carb should be blanked off.

Right hand connection on airbox goes to intake diverter, right side of airbox by the bulkhead.

HTH.

[fullsunian]

Doug,
Give me a ring mate....

[The Bobdogs]

Doug,
Give me a ring mate....

Don't listen to him Doug.....his mind it not what it used to be....he's barking mad he is.....

[fullsunian]

Doug,
Give me a ring mate....

Don't listen to him Doug.....his mind it not what it used to be....he's barking mad he is.....

[dazwatson]

Does this help

[dugcati]

perfectly - thanks

Sorry I didn't call you Ian - have not been on the forum since I posted that - not been on until now that is!

[avant-garde]

Hijack alert. Sorry about that but I only have one of those cables on my CU and that doesn't go to where it goes to in the picture!

...I assume it ain't going to make too much difference if the rest are missing. Also don't have the black bendy tube that is shown in the back of that picture coming out of the black round thing with the white wire - is that important? What is it?

Once again sorry to step in but I just couldn't help myself.

[dugcati]

Yes in theory you can get away with only the one the advance pipe which in the pic is the all black pipe coming in from the upper left of the pic and down to the dizzy.

The other pipes serve to actively retard the timing when the throttle is shut off/create a more controlled advance arc, dizzies have a sprung loaded plate which does this... I guess VW needed the retard action to happen faster/more reliably etc.

The white pipe coming in from the upper right in the pic is a warm air diverter that sucks in warmer air from the under engine area (near the fuel pump) when you open the throttle as far as I can tell - the haynes books merely refer to it as a "vacuum unit"

[BOXY]

Damn! must type faster!

The "cables" and "white wire" are nylon vacuum pipes. Has your engine got the right dizzie fitted? Missing vac pipes and the wrong dizzie could explain your van's lack of power. The one that's tee'd off the left side of the air-box retards the ignition timing to 4' ATDC, the one off the left-hand carb advances the ignition from 30' BTDC to 40' BTDC, and the one off the right side of the air-box is temperature controlled and operates the engine air intake. It lets it either suck air in from the engine bay or from the inlet pipe that runs towards the air vent on the right side of the van. I guess it's to help the engine warm up more quickly, but I'm not sure?

If you've got a dual vac dizzie fitted and the vac can is working you really need your timing set-up with all the pipes connected properly.

[Craig G]

The pipe that connects to the carb pipes (?) behind the air box (left hand side as we look at it)...what size do I need and where can I get some from?

Cheers

[Craig G]

The pipe that connects to the carb pipes (?) behind the air box (left hand side as we look at it)...what size do I need and where can I get some from?

Cheers

Anyone?

[BOXY]

Try your local hydraulic hose supplier. I think the nylon tube I used is either 5 or 6mm OD and the short pieces of rubber to join it to the servo / balance pipe was a bit of oil pipe that was a tight fit over the spigot.

[Craig G]

Yeah thats where I'm struggling, it really is a tight fit, not only slipping it on but also trying to manoeuvre my hands around.

Cheers