Carby Help

[pyrohamish]

What happens if I disconnect and these pipes and just block them off?

[altezzaclub]

You might solve a few niggling problems that occur by blocking all of them except the vac advance on the distributor, and I kept the charcoal canister vac as well.

 

I cut a 4" nail into 10mm pieces and pushed them up each hose. Looks fine, doesn't leak.

 

They were Toyota's attempt at anti-pollution on a carb much too old for it, and like most carb setups they get useless very quickly. Everything changed once fuel injection and computers got going.

[pyrohamish]

Can I just run the vacuum line from the dizzy to the intake manifold?

[altezzaclub]

I can't remember Hamish- Look up ported and manifold vacuum, I'm not sure which one the stock 4K runs, but its probably ported.

 

That means the vac drilling goes in right beside the throttle flap, so it is covered at idle. So you have no vacuum at idle, strong vac as you first open the throttle, and less vac as it opens more.

 

Manifold vac is strongest at idle and gets less and less as you open the throttle.

 

So your timing with ported vac is 8deg at idle, no vac, and the instant you open the throttle you get say, 15deg advance from the vac. Car gets up & goes..

 

Your timing with manifold vac could be 8deg at idle, but it would decrease all the time as you opened the throttle. Not so effective at adding acceleration.

 

When you're sitting at say 80kph and cruising with your foot lifted almost off, the vac advances the timing so the motor gets time to burn the very weak mixture in the cylinder. That gives you the most power from the small amount of fuel going in. When you boot it to overtake someone the vac collapses and timing goes back to whatever the dizzy has with the centrifugal weights controlling it. That stops it pinking and gives the correct advance for power.

 

When you go downhill with your foot right off, the manifold vac gives lots of advance to clean the weak mixture out with a good burn. The port vac will not do this quite as well.

 

(If you swap from your 8deg ported vac onto the manifold vac line the idle speed will jump a shitload of revs as you suddenly get max vac advance. That's the sort of effect vac advance has.)

 

Try both and report back with the effects!