Curious about how to set the carbs up.The timing is close but may be out slightly.I started by turning the air mixture screws all the way in and than backing both off by 2 1/2 turns to start. I let the car idle and than I move 1 side until the car runs rough than back off the other way about 1/2 turn.I did the same for the other side. It runs ok but pops through the exhaust every now and than.It gets better when I take the throtle linkage off.I think my biggest problem is seting the idle speed screw. Is there something I should do prior to starting any other alignment?I read the procedure but I am stumped. What typically causes it to pop through the exhaust?I did check the vacum on both sides and they are real close ( within 1 of each other).

By the way it seems to smoke through the breather. If I take the oil cap off it has a ton of pressure coming out?

An exhaust leak.

You have an exhaust leak - probably- and you are pressurizing the crankcase - not good - do you have any breather hoses from the heads or the oil cap area, where do they go?

Make sure to sync the airflow for the left/right carbs. You want them flowing the same amount at idle and you want both carbs to hit WOT at the same time.

How about a few pics of the setup?

Here's how I sync duals. . .

First ensure all your linkage is connected and symmetrical (cross bar type linkage) you want your drop links to be as close to straight up and down as possible as well as even between the left and right side. If one is at a severe angle compared to the other, you will have problems because one carb will always lag or lead the other later.

Then, with engine running, disconnect one of the linkage arms so that the carbs are totally separate and sync the air flow through them with a syncrometer.

Then reconnect the linkage arm and tighten it into place. I find it better to do this with the engine idling so I can hear changes as I connect the link. Re check with a syncrometer to ensure they are still even at idle and exactly where they were before the linkage was attached. If anything has changed, adjust the linkage arm to get it even again at idle.

Then put your finger on one carb throttle arm and closely watch the other while you gently blip the throttle with the other hand where the cable attached (that is really important because if you use another part of the linkage to blip the throttle, it could be twisting and flexing the linkage in a way that it does not normally flex while driving). See/feel that both arms are beginning to move at the EXACT same time. This will ensure that you have a smooth throttle response off idle.

Next with the engine OFF, ensure that at WOT both throttle arm hit their stops at the same time. If they don't, the Geometry of your linkage arms is off and you will need to re-adjust things so that they can both get to WOT at the same time AND idle at the same time.

Once you have the linkage perfect, then you can move to the mixture screw fine tuning. I prefer to do this with my eyes closed so that I can concentrate on the engine speed better, but that's just me (IMG:style_emoticons/default/smile.gif)

Hope this helps. . .

Here is the only pic I have right now with the engine out of the car.I just recently installed new rings, bought new carbs, and installed elctronic ignition. It only started to smoke real light out of the breather after making adjustments to the tim ing and valves. Do these engines typically have pressure and smoke where I described? How concerned should I be?

I think this is a slightly improper description, which I've seen reiterated many times. The symmetry of the linkage is irrelevant as long as the butterflies are both closed completely at idle and hit WOT at the same time. I fear that emphasizing the symmetry leads people to focus too much on the looks of the linkage and takes away what they should be focusing on, the actual operation.

I've heard of people pulling out tape measures to equalize their linkage. Which is the WRONG approach. I've synched a linkage that was certainly NOT symmetrical, but hit idle and WOT perfectly.

I'm not trying to attack you, Nate. Just a general perspective of mine.



---Joe,

You should get some air flow from the crankcase breather. You would be best served by investing in an actual breather box. What you might be noticing is that as the oil vapor coalesces in the cone filter you've got, it starts to get blown out into the engine bay as vapor. Your setup will absolutely cover the engine in a ugly, oily spray within a few hundred miles.

Is the motor new or old? 1.7?

Its an old 1.7 that had no compression on a couple cylinders when I got it. I agree that it is more vapor than actual smoke. Deffinently vapor from the oil cap.What causes this to happen and should I be concerned. Like I said it did not happen until I adjusted the valves and timing.Also all of my hardare for the exhaust is tight? Im not sure where I could be getting a leak? It`s a little pop and sometimes mostly has a low ressanance sort of base like a drum.
Where do I get a breather box? Sorry for all the questions at once.

Try this.



Just had a crazy problem an this fix it, just like a VW setup.

Jake Raby sells a breather box.
Chris Foley sells a breather box.

But if you're looking for something quick and dirty, this one from CB Performance will work. And you can find them used on TheSamba.com for even less.

The exhaust can seem tight and still have a leak. Getting the pipes to seal to the heads can be a PITA!

A little trick I learned from fiid & mightyohm is to hook up your ShopVac so it's blowing, then carefully tape the hose (or use a friend) blowing into the exhaust (blowing backwards towards the heads). Then you can crawl under the car and hear/feel where it might be leaking.

Sometimes people think they can feel for leaks with the motor running, but the air from the cooling system is always blowing there, so you can't feel anything.

And things may have 'changed' since you set the timing/valves because now the motor is running better and perhaps you have hotter exhaust, or some other condition that was bad for performance, but was preventing the backfire. Problems masking problems.

You have to take the long systematic approach and deal with each problem as it becomes apparent. Everything done right is a step forward, even if it feels like a step backwards.

My new ignition came with a vacuum advance. I hooked the lines from the carbs to the distributor advance. I placed a "t" between the carbs and ran it to that way. Should I bring vacuum from both carbs? I have the ports on the manifolds blocked off still but I guess I could run a hose from them. What are these ports for anyway?

The port with thr red cap should NOT be used for vac adv

if you exhaust is leaking, get a small 2*4 and hold it flat against the tailpipe with the car running. It will make the noise really loud so you can trace it.

Rich

Get a non-contact thermometer and check the exhaust temperature you will find
the rear two cylinders are running cool as compare to the front cylinders by
tying the two manifolds together this will cause the rear two cylinders to draw
gas now. I just went through this,that's why VW tie them together to correct
the problem at idle.

So am I actually going to link both carbs together where the red ports are than t it off somewhere between or are they run seperately?

Just connect them together.

Easy enough--how about for the vacum advance. Should I have placed a "t" between both carbs and ran it to the distributor. Thats how I did it and to be honest, other than the poping it runs pretty smooth.

I understand what you're saying and your right; no need to be identical so leave the tape measures in the tool bag. (IMG:style_emoticons/default/smile.gif)

I only bring that up because I see all the time where a client will bring in a car with duals complaining that they just won't run right and they have one drop vertical and one at about a 45 degree angle. . . (IMG:style_emoticons/default/rolleyes.gif) They have no idea that it makes a difference. You get the drops closer to each other and magically things begin to fall into place and work as they should.