Jetting 34ICTs for 1776

[Stufenheck]

Its likely that after 1800 mile drive the engine has vacuum leak.
The intake gasket may have been compromised after 5000 miles of high engine temperatures.
If there is balance tube or hose check it for spits in line or cracks in the pipe.

The F78 emulsion tube seems to ask the idle jet do more of fuel enrichment and there is not enough fuel flow in the fuel circuit for the main jet to come on sooner.
The F5 emulsion tube seems to do a better job in this regard. In my car it made a noticeable different in how well it drove.
Simple test is try driving the car without one of the idle jet installed. What you find that idle jet does most of work below 3K RPM.

Also ambient air temp and humidity affect the engine performance.
When driving from North SF Bay area out to Central Valley, notice that the engine behave differently to the point once in the central valley, needing to perform a carburetor adjustments.
Stopping safely on the side of the road then attaching a portable tach and adjusted volume screws to get highest RPM.
Once at my destination I would repeat the volume adjustment before turning off the car.
The only thing I would attribute the change in temperature of 20-25 deg and decrease in humidity.

[kangaboy]

Well i just took the carbs apart. In the float bowls there was some type of gelatin. Really weird. I guess some left over carb cleaner mixed with the gas or something and then set. I have never seen it before. Either way, i cleaned them up, and will be getting ready to re-install them. Im going to make sure the floats are set correctly, then just block off the balance tube ( i tried to put some vacuum on it with my mouth and it leaked, so may have been the initial problem). Ill re-install it later, but just for now i wanna get this thing idling again. Ill be putting everything back together and letting you guys know what happens....

[kangaboy]

ok, well got everything back together. changed a fuel filter, and bought vacuum caps to cap off the vac ports for tuning. fired it up and the same thing. it idled for one minute, then worthless.
The throttle shafts have a little play in them, could this be causing a vac leak through the shafts? I cant explain this situation at all. It worked before i took it apart, and now its worthless.

[kangaboy]

So what should i do now?
I have already taken everything apart and cleaned and remounted it...
It runs great off of idle, and i can drive it, but it cant idle.
One time I thought i had it good to go, but come to find out the right carb got stuck open a little, and the throttle screw was like 1/8" off the stop.
I have no more ideas, can you guys help?

Im tempted to ditch these durn things and get some Kadrons, or a single mount 44 or 40 IDF.

[Stufenheck]

From what I recall ICT with throttle shaft play require a little more volume adjustment to compensate for shaft vacuum leak.

Here are a few ideas that you may want to try.

Do the intake manifold have balance port? If so make sure to connect both them together. Helps with idle performance.

Try to remember if the ICT have a port line on the base if so make sure these are plug. Possible source of vacuum leak from crack or split plug.

Do you have a synchronizer with dail gauge? To balance air flow between carbs. Can start with high idle the adjust down slowly to get an idle at 1000 RPM when cold and 1200 when warm up.

[kangaboy]

I have a snail sync, and i have actual vac ports coming off of the carbs, not the manifolds, and they are capped (for now until i get them idling, then they will have a balance tube "T"ed to the SVDA). I guess ill just turn the idle adjustment screw in until they idle, and get bigger jets when i figure out wtf is happening.
Any other ideas?

[Stufenheck]

I have a snail sync,

Are you able to fit it snugly in the carb throat?

i have actual vac ports coming off of the carbs, not the manifolds, and they are capped (for now until i get them idling, then they will have a balance tube "T"ed to the SVDA).

Do not connect the SVDA distributor to the these vacuum ports, but due connect them together. ICT's lack proper vacuum port for the distributor vacuum advance.
Also the ports may be to small to balance intake pulse between two cylinder heads. Most single carb intake require balance ports that are 1/4"- 5/16" ID for dual port and to >1/2" ID for single port heads.
See attached picture type 4 ICT intakes with engine vacuum ports.

60 idle jet is all is need to get the car to idle.

In the being of this posting the distributor was an 009.
Did car run better after installing SVDA?
SVDA distributor still using points? if so check the gap?

[kangaboy]

Alright, got some updates.
I went and just turned the idle adjustment screws till the thing would idle. I got it to idle with both screws turned in 5 turns, which is insanely high.
Both carbs are now connected via balance tube. I checked the tube and it is solid with no leaks.
While the car is idling, which is about 1100 rpm, it fluctuates a bit in rpm. It will drop for about 10 seconds to about 600rpm, then bump up to 1200rpm, then back down to 600 rpm after a few more seconds. I can turn the mixture screws in or out all the way, and there is no change what so ever. I put the snail sync in and the carb reads something ridiculously high like 25 or 30. Funny that the car actually idles higher when i stick the snail sync in, which points towards a vac leak.
I sprayed both carb areas with wd-40, and idle didn't change at all.
Another thing i noticed is that 3-4 side valve cover is much cooler than 1-2 side after running for a few minutes.
I double and triple checked firing order, valve adjustment, and wires.
I was using the walmart "lubricant" to check for vac leaks, and i dont know if it is flammable enough to show a vac leak. I have checked mostly everything, and the only thing i can think is that the throttle shafts are causeing a big enough vac leak to cause this problem.
Now i think i need to figure out who can re-bush these bastards and HOPE that is what the deal is...

[Stufenheck]

If you need to rebush your ICT contact Mark Harvey.

His website and Samba ad links.

http://www.carburetorclinic.com/services.html

http://www.thesamba.com/vw/classifieds/ ... id=1223596

You may also want to add larger balance port to intakes.

At least the size on this Type 3 ICT intakes.

MVC-630S.JPG

[kangaboy]

ok, so this is the fourth weekend of working on these buggers.
I was figuring vac leak, so i took everything apart...again.
I got the carbs off and was playing around with them, when i noticed that the left one wasnt shooting out gas when you hit the throttle. The right one shoots a bit, but i think the left one is clogged. I checked the jets, and took them out and swapped them between the two carbs an put them back, and still the same thing. Its like when you pump the throttle and accelerator pump, it just shoots gas around in the float bowl. Like its trying to go somewhere but is getting backed up or clogged and not going out of the accelerator pump like it should.
So i guess im going to try and get some really fine wire and root around in there for a while tomorrow and see if i can unclog some stuff, seeing as i dont have an air compressor. If that jet or line is clogged, than hopefully my idle circuits are clogged as well, which would put an end to this whole issue when i get them unclogged. I let you guys know what i come up with in the morning.

[kangaboy]

Finally!
I took the time to clean out every single pathway, and every jet, and sprayed up every little hole and actually found out where each of them go...so all in all i know a little more about 34ICTs now.
Any way it idles at around 1000rpm now, and both carbs are set at about 8 on the snail sync. Im going to take a run to the beach and see how it all works out.
I have a few more questions so tune in shortly for those

[Stufenheck]

Finally! I took the time to clean out every single pathway, and every jet, and sprayed up every little hole and actually found out where each of them go...so all in all i know a little more about 34ICTs now.

Glad to hear you sorted out the issue with ICT's.
There good carburetor when properly set up.
Track down the source of any debri in the fuel system including rubber & tunnel fuel lines and gas tank.

[kangaboy]

So the weber guide says that if u turn the idle screw in more than three times in total to bump up the idle jets. Mine r turned in about 3 1/2 to 4 turns, so should I bump up the jets a bit? And how do you know if you need to change the other jets to supplement the idle? I'm looking for mpg here, not brute force or hp.

[Stufenheck]

You can try next size idle jets, but recommend replacing the F78 emulsion to with F5.
http://www.piercemanifolds.com/SearchRe ... Search.y=0
What is your current jetting?

[kangaboy]

Im going to go,
170 Air,
145 Mains,
60 Idle
Any thoughts or comments?