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Fri Nov 21, 2008 8:56 am

I have been working on a set of Weber 34 ICT's for a while now and they are really trying my patience.

Here are some specifics to the engine they are mounted on:

1776 w/ 40x35 unported heads. Compression set at 8 to 1. Cam is a Scat C25 w/ 1.1 rockers. Exhaust is a 1 3/8 header and single muffler. This engine is in a Type 3 Fasty. Carbs are, of course, Weber 34's, with the main jets: 140, idle: 60, with all else stock from factory.

Now the problems and what I have done so far. The engine, at idle, runs fine. With it heating up, begins to stumble at take-off and wants do die. The carbs leak fuel past the needle valve and seeps out the throttle shaft. Gas will also drip from the venturi nozzle. Mid-range driving seems soggy at best. The engine does not belch out black smoke but does puff it out when revved. When this engine is put in gear (its an auto) it acts like it wants to die. In nuetral or park, it does fine but revs high. It did backfire bad but did stop once valves were set right. The engine, once hot, runs on when shut off. Not all the time, but does on occasion.

Now, what I have done. The carbs were not flat on the bottom and were machined flat to seal properly to the manifolds. Carbs were rebuilt and had the floats set to 6/13mm. I have checked and adjusted the valves to .006 and even set the timing at 7.5 degrees. (has a 009). Sparkplug gaps were checked at .026". Points gap is .016". I have adjusted the carbs to Redline and Pierce Manifolds website and still no luck. Carbs were sync'ed and show 10/11 on the snail. Way high, I know. I take it to 6/7 on the snail and it dies. I pulled off #1 and 3 spark wires and no change in idle.

What have I missed? A possible vacuum leak between the heads and manifolds? Too rich in the mains? Idles? Any help would be appreciated on this matter. I am lost...

Thanx...

Fri Nov 21, 2008 9:33 am

Have you measured your fuel pressure?

If the fuel pressure and float adjustments are correct, and the floats are not full of fuel, you might have leaky float valves.

Scott Novak

Fri Nov 21, 2008 9:50 am

I will be ordering a Holley low-pressure regulator for the vehicle. It does have a rotary pump but I don't know the pressure. Thanx...

Fri Nov 21, 2008 10:55 am

veedubcrazy wrote: and even set the timing at 7.5 ATDC. (has a 009)..

every single 009 is different. you should set it at max advance first. between 28-32 degrees BTDC @ 3500 RPM. once you've done that, see what your timing is at idle and that is what it is FOR THAT 009.

Fri Nov 21, 2008 11:06 am

bon2198 wrote: veedubcrazy wrote: and even set the timing at 7.5 ATDC. (has a 009)..

every single 009 is different. you should set it at max advance first. between 28-32 degrees BTDC @ 3500 RPM. once you've done that, see what your timing is at idle and that is what it is FOR THAT 009.

Well, on the pulley for the Type 3, there is no way to know the max advance of 28 - 32. Unless there is something I don't know...

Fri Nov 21, 2008 11:31 am

veedubcrazy wrote: bon2198 wrote: veedubcrazy wrote: and even set the timing at 7.5 ATDC. (has a 009)..

every single 009 is different. you should set it at max advance first. between 28-32 degrees BTDC @ 3500 RPM. once you've done that, see what your timing is at idle and that is what it is FOR THAT 009.

Well, on the pulley for the Type 3, there is no way to know the max advance of 28 - 32. Unless there is something I don't know...

well that dizzy might very well be part of the problem, because if you can't set it to max advance then it's not being set correctly.

Fri Nov 21, 2008 11:41 am

You could use a dialback timing light.

Or you could add timing markings to the pulley.

Personally I'd recommend confirming where top dead center is. I remove the number on spark plug and CAREFULLY insert a rod into the spark plug hole, then while pressing the rod against the piston top, rotate the crank back and forth just a little bit by hand and feel when the piston is at top dead center. Then I check the marks on the pulley to see where they line up.

The steel rod I use is a hitch pin for my trailer hitch. It's too long to fall all of the way into the cylinder. The end of the pin is rounded so it won't scratch anything. You want to be very careful with this and not rotate the crankshaft too far or you will damage something.

This discussion shows some photos of pulley marking.
http://www.thesamba.com/vw/forum/viewtopic.php?t=291949

After yo have determined where the top dead center mark is on your pulley, you can remove the pulley from the engine. Then measure the circumference. Metric measurements make this easier. Divide the circumference by 360 and you have the distance per degree. So I would take the number of millimeters per degree and multiply that by 30 and measure that distance from the top dead center mark and I would file a small notch into the pulley. I'd also multiply the mm per degree number by 25 and 35, and also mark out 25 degrees and 35 degrees on the pulley. So you would have marks at 25, 30 and 35 degrees. I'd paint the marks that I filed so that they are easy to see.

Your spark timing at full advance will probably be set between 28 and 32 degrees approximately.

Scott Novak

Fri Nov 21, 2008 11:51 am

Scott Novak wrote: You could use a dialback timing light.

Ahh, I will get one. :D

Fri Nov 21, 2008 2:01 pm

i have duel 34 solex's on mine and i was having the same problem , and i also run an electric pump, that was labeled at 2-4 psi . i tested it and it was putting out like 5 1/2 psi , way too much for small solex's or webers. i put a regulator on mine and now have it reduced to 2 1/2 psi and it fixed the problem.

Sun Nov 23, 2008 12:33 pm

i had a very similar problem and i ended up setting my timming at 34 deg. btdc and checked the fuel press and fixed that, the car ran fine after that. those are supposed to be the simplest carbs but gave me the most hell try a degreed pully only 25 dollors. good luck just my experience

Sun Nov 23, 2008 3:23 pm

veedubcrazy wrote: ...The carbs leak fuel past the needle valve and seeps out the throttle shaft...

There's your problem. If fuel is leaking out throttle shaft(s) the bushes are worn - will be a pig to set up until they're replaced as when fuel is not leaking out, air will be leaking in and fuel air ratio will be out.

I'm not up on type 3 engines. Do they have mechanical or electric fuel pump? If its mechanical and same as 1600dp type one engine you definately do not need a fuel pressure regulator, ICT's will run fine on stock vw pump.

Sun Nov 23, 2008 4:36 pm

On 68-73 type 3s it was an electric EFI fuel pump, but.... he already said he's got a rotary electric pump in there now.

When the engine is running, there shouldn't be any drippage from the throttle shafts. Not unless the carbs are really really worn, with an overflowing bowl from float/needle/pressure issues. (And this one might have some issues like that, but I'd get the total advance and fuel pressure issues dealt with first)

One can do the old ether test to see just how bad the throttle shaft bushings are - get the idle set up smooth and then spray a little ether starting fluid right at the throttle shaft and note how much the engine speed changes.

hemi wrote: hell try a degreed pully only 25 dollors.

He can't, unfortunately, as it's a type 3, and their timing marks are part of the cooling fan assembly.

-Andy

Sun Nov 23, 2008 5:13 pm

Guys, I am going to be getting the Holley regulator tomorrow and try putting it on Tuesday. I am also going to swap out the 009 with my 010 and see if that does anything.

IIRC, the fuel pump in now is the same as it would have been for the fuel injection. Not 100% on that though but it is an elec. pump up front...

I will keep posted here...

Sun Nov 23, 2008 5:20 pm

veedubcrazy wrote:
IIRC, the fuel pump in now is the same as it would have been for the fuel injection. Not 100% on that though but it is an elec. pump up front...
...

Hopefully you don't have the stock pump in there! The EFI fuel pump is entirely inappropriate for carbs!!! It's designed to operate to a regulated 28-35PSI. That's over 10 times as much as you're going to need, plus without the original Bosch fuel pressure regulator shuting fuel to a return line, that pump might give a lot higher pressure than that.

Sun Nov 23, 2008 5:24 pm

Yes, I know...but not 100% on that. Hopefully I will know more Tuesday...

Sun Nov 23, 2008 7:02 pm

I recently picked up a weber itc34 at the swap meet for 5 bucks dont know much about it.

Tue Nov 25, 2008 7:55 pm

Okay, I have put in the Holley FPR (12-804) and it was not too bad an install. One thing I noticed right off was that the carbs did not drip from the venturi nozzles as before. Nor was there any weeping of gas from the throttle shafts. Not bad for a $29.99 investment. Still idling high like a vacuum leak exists.

I will look into that on Sunday...

Sun Nov 30, 2008 4:30 pm

Okay, seemed to have cured the high idle, not sure where though. The intakes were taken off and made sure the contact surface to the heads were flat. They were. Replaced the old intake gaskets with thick ones with a bit of grease to aid in the next removal. Replaced the gaskets between the carbs and intakes with good thick ones.

Also replaced the throttle shaft seals as well. New spark-plugs were installed as well. The off-idle stumble is gone and the top-end accel is back. The jetting in the carbs are 60 idles, 140 mains. All else is stock.

It still runs on after shutting off but thats timing, I beleive...

:D

Sun Nov 30, 2008 6:04 pm

veedubcrazy wrote:
It still runs on after shutting off but thats timing, I beleive...
:D
Get a tac and check the base idle of the engine and then check the timing