nick1

i've removed my emisisons, and was just wondering what to do with the 2 vacum lines that go to the thingies on the distributor. should i block them off, route them together, or just leave them be???

rxtasy3

iTrader: (2)

if ur not going to have vac advanced, leave those on the dist open, do not plug them.

nick1

should i have vac. advancing? or is it not possible now that i've removed my emissions?

drittens

http://maz_tutorials.ten15.net/

they plug the distributor lines into the carb plate.

nick1

by carb plate do you mean that "spacer thingy" that sits between the carb and the intake with all the vacum lines coming off it? if so, i don't ahve that thing anymore, i removed it

drittens

yeah, so i dont know, sorry - I tried.

REVHED

Why on earth would you remove it?

nick1

because i removed all my emissions. plus actually the real reason is the carb/intake i bought didn't have it so i left it that way. as far as i can tell, its not needed once you remove all your emissions, and not just the rat's nest but everything.

this is really the only problem i've run into, but if its not necessary, then im not worried. but doesn't the vacum advance help with performance? or should i basically just leave it advanced all the time now that i don't have the vacum? will that affect fuel economy?

Weed Wacker

You can leave the "distributor thingies" unhooked and open to the air. you wont have any vacuum advance like everyone else said which could be a good thing depending on your setup. But try to find a carb spacer because it should still give you better bottom end and maybe a little better fuel economy, just plug all of the vacuum nipples on it. The reason for taking the vacuum advance off is so that on a car that has more timing in like a ported motor or something, it doesn't give too much timing and start to detonate, thus shortening the life of the motor a great deal.

Rx7Kidd

if you hook them together and adv the timing you get some hp gains. dont really know about if you get a spacer if it really helps on fuel economy.

vipernicus42

iTrader: (4)

Do as everybody else says and leave them open to air

Rx7Kidd, what basis to you have for "hook them together..." ? They're actuated by pressure. If they're not hooked to a controlled vacuum source they should be left open to air because if you block them (or plug them to each other) your timing will change with the relative atmosphereic pressure. Open to air = equalizing pressure inside and out = no timing change. (as I understand it).

hp gains from vac advance vs. non vac advance on a stock port is debatable, they're probably negligible.

However you *will* notice your fuel gauge needle dropping faster w/o vac advance

Jon

Rx7Kidd

well ive done so and it works fine, i mean i know there is no vacuum put to it but it basically blocks it off, so you adjust your timing to adv due to the fact. you can leave them open, wasnt saying you couldnt.

REVHED

Just because you've done it doesn't mean it's correct.

vipernicus42

iTrader: (4)

Do you understand pressure at all?

Fill a balloon with 3 Litres of air at STP (Standard Temperature and Pressure : 20 degrees C and 101.3kPa) and the balloon will be a certain size. (let's guesstimate and say about a foot diameter)

Now raise or drop the pressure in the room with all other variables staying the same. That baloon (which still has the same amount of air in it) will get bigger or smaller (bigger = lower pressure, smaller = higher pressure).

Why? because there's a fight going on between the pressure exerted by the air IN the balloon, and the air outside the balloon in the rest of the room.

The less resistance on the balloon (lower room pressure) the further the air inside the balloon can push the balloon before equalizing.


Now what do balloons have to do with vac advance? Well if you picture those little vac advance thingies little metal balloons that have a movable diaphragm in them which acts as a pressure sensor. The metal casing won't get bigger or smaller, but instead there will be more pressure put on the sensor to try and "equalize" the pressure between the inside and outside, increasing or decreasing the timing.

If it's capped, it'll raise or lower your timing based on ambient pressure (and temperature too actually). If open to the air, the expanding gas will just escape and the pressure inside and outside will "equalize" so you'll never get any unexpected advancement or retardation of the timing.


Now if you can offer me a better explanation than that as to why you should cap the vac advance instead of leaving it open, I'm always open to correction

Jon

Edit: How old are you Rx7Kidd? If your HighSchool has an advanced Chemistry class, it's probably covered in there somewhere. Go ask your Chem teacher about PV/T (The relationship between pressure, volume and temperature) and STP (Standard Temperature and Pressure).

vipernicus42

iTrader: (4)

It also explains why your ears "pop" when you drive in the mountains or go swimming in the deep end. Did you know there are little balloon-like organs in your head?

Jon

no_name

I knew that stuff lol. The vacume lines for the dizzy plug into a t, and then i belive is the second hole from teh left on teh carb spacer. I am removing teh emissions on my car and that is where it goes. You will also keep your vacume advance that way. You are going to have a problem because you have no spacer. The lack of a spacer should also create some other issues, and you are probably losing, or maybe gaining a few hp. If you elongate the route that air has to travel to get to the engine, you change pressure dynamics.

Ted

nick1

any other people have anything to say about the spacer thingy between the carb and the intake? the carb/intake i installed on my "new old" motor just did't have it, and i assumed i didn't need it due to not having emissions, although now i've run into this issue with the dizzy vacum advance....so.

is there anywhere else i could hook the distributor vacum advance thingies to or would that spacer thingy be the only thingy that i can use?

vipernicus42

iTrader: (4)

Don't worry too much about the spacer. If you have no emissions it's not *necessary* as long as you have a good seal between the carb and the manifold.

On mine I tried to remove the spacer and just put the carb there, but the studs are too long and they hit against the carb body. So there'd be a gap either way. If yours is sitting flat, he may have ground down the studs or cut them or something....

Jon

no_name

I would not worry about it, Soviet Canuckistan said it best. As for teh vaume advance I am sure there is a way do get around having the spacer. You could probably drill and put a little tube somewhere in your carb to do the job. You should talk to a machinist, or somone who knows carbs well (I know jack all about carbs), and you could probably jerry wrig something.