hey im about to attempt a quad carb conversion on my mates 1200 ute. ive got some mikuni 29mm smoothe bores and was just going to make up a manifold with a single pipe going to each carb but im puzzled as to what i should do with the pcv valve that goes onto the standard intake manifold. would it work if i just plumbed this into one of the pipes? any advice would be good

cheers
benno

dont put it in simple twin weber setups dont use pcv's

ah to nice. thanks a lot

The 'simple twin Weber' instalations are also illegal for no other reason than the fact that the engine no longer complies with the relevant ADR [ADR27, 27A, 27B, .. depends on the year of manufacture, check your compliance plate] The PCV is a requirement of the act since it was original equipment on the engine.

If you run a pipe across the top of your intake runners, front to rear, closed at the front end & threaded for a PCV valve at the rear, with a small connecting hole between each intake runner & the pipe, you will be at least seen to be attempting to comply with the requirements of the act. It will also act as a balance pipe for your quad setup.

You will also be doing your engine a favour since it was the invention of the PCV system along with improvements in engine oils that all but brought an end to sludge buildup along with oil contamination with water & sulphur [resulting in mild sulphutic acid in the crankcase] & a number of other nasties that get past the rings on even a new engine.

If you use the bike carbs you will also have no ported vacuum for the distributor, but that may not really matter because your vacuum signal may be very low anyway.

ah right thanks for that dodge i might just do that. could i just plumb the distributer vacuum into the pipe that i have going across the top of my runners for the pcv also?

Bad idea.

What's needed is for the distributor to see NO vacuum at idle. In a standard engine, this is when the vacuum is highest, so it was necessary to make a special port in the carb that drew vacuum from a point that was located just above the throttle plate when it is closed.
When the throttle is opened, this port can see manifold vacuum, but when closed, it is exposed to atmospheric pressure & there is no vacuum advance.
This is why it's called 'ported vacuum'

Your only option is to do without vacuum advance & simply cap the fitting on the vacuum canister.

ah right okay. i really only know the basics about this sort of thing. you guys know your stuff thanks a lot