Building a Stock ish Type 1 engine for the 1971 VW Bus?

[richparker]

I’m running a 30mm pump with a Burg relief cover and I see 40 psi when cold and around 25-30 when warm and idling. Haven’t seen any pressure over 40 when cold, warm or at speed. I Understand that as a rule of thumb it should be 10 PSI per 1000 rpm, but my builder and all the others I’ve talked to about it all agree that it’s fine.
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’71 Westy build
Adventure thread
’65 Deluxe Build

[Danwvw]

I am having an Issue with the NDIX-32 Zeniths running way too rich! See it in the last 10 seconds of this one minute long video. Look closely down the throat of the carburetor and see that when the engine revs fuel dribbles out the main's. Both carbs are doing this, I think float levels are ok, maybe not? This right one has 2 or 3 millimeters higher fuel level than the Left Zenith which measured 23mm down, the Spec. is 19mm down. Also I have checked the fuel pressure and it's 2.5 lbs however it drops when the engine is revved. The Engine other than running very rich is running and idling beautifully! Sorry the video isn't longer the camera shut off again.

Link

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[SGKent]

I had that happen on an Opel GT when the gasket I chose had a different hole placement than the original and I missed it. If you have foam floats the height means nothing if they are soaked and heavy.
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"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[Danwvw]

I am thinking through what you just said, and I appreciate your commenting, very few people are running Zenith's anymore, it's hard to find anyone that's interested.
On my Zenith NDIX-32's the main fuel circuit is pretty straight forward the main jets for all practical purposes are located low inside the float bowl, the main fuel passage and what they have labeled in the diagram below as the "Main Spraying Assembly" also press fit into the body. The Main nozzle slopes down into the Auxiliary Venturi coming out there a what looks like is just about the same level as the fuel level.
It makes me wonder if the 19mm fuel level spec. down from top of the body is correct?
The only thing I can figure is the float levels are high maybe like you mention it's heavy floats or something. Also I need to check that my 1.15 Main jets haven't been drilled out and that they seat well in the body and fuel isn't getting around them somewhere. This all means pulling the carbs from the car for sure. I did find this page 356 Registry and it says to set the fuel level with 1.5mm washers I used .037" fiber washers that is less than 1 mm so this gives me hope it is just the fuel level set too high.
356CarburetorRescue Diagram.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Danwvw]

Found this: Ron Ladows Zenith Tuning Info.
"Adjusting the float level is first and very important. It is measured with a special tool or the ‘tail’ of a caliper after removing the carb top. It is also measured to the top of the meniscus; at the top where the edge of the fuel fades in to the wall of the container or ‘jumps’ to the tail of the caliper. The spec for all Zeniths is .728″ (18.5mm) +/- .04″ (1mm) below the carb body gasket surface"

This method of measuring fuel level should help get it lower too!
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Danwvw]

Today I took the tops off the Zenith NDIX-32's and installed more washers also measured float weights and checked fuel height before, will have to open them up again to get fuel height reading with the added washers.
Zeniths both still dribble Gas but not as bad, #2 hardly dribbles now but it had the lowest fuel level as the car was not level. (Fuel level estimates before, Left Carb 18.2mm, Right Carb. 19.67mm)
Almost out of threads:

Left Carb Float measured about 1 Oz. others 1.005 and 1.050 Oz.

#3 fuel measurement 15.05mm before adding .61mm for a total of 2.8mm of washers to the Left Carb:

#4 Fuel measurement 21.35mm before changes:

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Danwvw]

Just finished the "Test Drive" Mixed results. Seems to run plenty strong however it may have a problem with #2. I leveled the car and revved it, #2 is popped a little but #2 is not dribbling like the others. Also getting an acceleration delay now when I give it throttle. I think there's been something wrong with #2 all along and the reduced float level just shows up the problem.
When the new idle jets arrive 0.45's currently 0.50's I will pull the carbs off the car for the installation and do some cleaning. Also I can install 2.30 Main air corrections jets currently they're 2.10's and see if that helps the dribble.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Danwvw]

Leveled the car better and took fuel level readings near the front to back center of the carbs. After the readings below were taken installed (1.3mm Washers Rt Carb) (2.2mm Washers Lf Carb) No readings on the new settings yet, But in the test drive the car ran strong without the hesitation I was getting with the previous settings. I can still see drops of gas coming out of the mains, not too bad though, drops of gas seem to break up better. Probably will remove the carbs and give them a full cleaning next.

21.87mm reading on the Rt. Carb with the 1.5mm Washer:

Rt Carb Measurement Location:

22.44mm reading on the Lf Carb with 2.8mm of Washers:

Lf Carb Measurement Location:

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Danwvw]

Out for a Sunday Drive, 1679cc Running Nicely!

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Danwvw]

With Homemade Electronic 6 Volt Voltage Regulator installed inside the Bosch mechanical regulator housing:

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Danwvw]

Hi, Everyone, I wanted to ask for information about fuel Pumps, This "stockish 71 Bus engine" with dual Zeniths shown above has what I think may be the Original Fuel Pump on it and I have the WW kit but have not installed it yet. Normally it's got about 2.5 lbs of pressure. But it does loose about 1 lb of pressure when the engine is reved. Is this a problem? Also it leaks oil around the shaft.

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[SGKent]

sounds like a supply issue - check the sock in the outlet to be sure it is not restrictive.
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"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[Danwvw]

"Stock"? The screen in the pump? Yeah, it's all been gone through but it could need cleaning again. I did put a metal inline fuel filter on it weeks before and the gas tank filter got cleaned last year along with all new gas lines. It does deliver gas pretty slow though to where the rubber fuel line connects to the metal line where it comes out near the engine under the car. I know because I drained the tank when I swapped engines. It was just a slow flow taking maybe 5 minutes to drain the last gallon. If this is a problem then I probably need to eliminate the pet-cock, Are Pet Cocks too restrictive for Dual Carbs? The other thing is it's still running too rich too as I have yet to re-Jet as I had planned.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Alan Brase]

This is where spelling matters. Steve said "sock", not "stock".
He means the thing under the fitting at the bottom of the tank. Early ones were brass screen soldered up.
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Al Brase
Projects: 67 sunroof bug, 67 Porsche 912 Targa, 70 Westy
Dec 1955 Single Cab pickup WANT 15" BUS RIMS dated 8/55, thru 12/55
To New owners: 1969 doublecab, 1971 Dormobile
Vanagons:
80 P27 Westy JUL 1979, 3rd oldest known US
83 1.6TD Vanagon, 87 Wolfie Westy daily driver, swap meet home

[Danwvw]

Thanks Alan for catching my misunderstanding, You guys might be on to something as last year when I rebuilt the Pet Cock I did accidentally break off an inlet tube and I soldered it back on.
Looks like the short tube was left alone, I should try measuring that fuel pressure drop again with it on reserve.
This video is one I took before making this post so it would have been with the pet cock in the up position "Long Tube"
(Note! I Later discovered My fuel pressure gauge is out of calibration and reading 1 lb low so it was actually about 2 1/2 lbs with what looks like from this old video a 1/2 lb drop in pressure revved.)

Link

Last Year:

Before Breaking it:

Repaired after breaking it:

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Alan Brase]

I'm guessing this petcock is not on a bay window, tho the thread seems to be in bay window forum.
Great job choosing the Zenith carbs. Good German stuff, but a bit of a learning curve.
Also, good for you knowing and mentioning the screen filter inside the fuel pump.
I'm currently working on a petcock bus, a 1956 single cab.
I often thought it might be better to leave the sock out, then put the filter UNDER the tank At least that would get the problem sediment into an easily removable place.
And here's my biggest point: If you SOLDERED on the petcock, you may have damaged the rubber which might be now partly plugging the passage. Time to put a new rubber part inside the petcock.
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Al Brase
Projects: 67 sunroof bug, 67 Porsche 912 Targa, 70 Westy
Dec 1955 Single Cab pickup WANT 15" BUS RIMS dated 8/55, thru 12/55
To New owners: 1969 doublecab, 1971 Dormobile
Vanagons:
80 P27 Westy JUL 1979, 3rd oldest known US
83 1.6TD Vanagon, 87 Wolfie Westy daily driver, swap meet home

[Danwvw]

"Alan" Thanks for the reply, I think the problem is more the tube size at least in my case, mine may be restricted due to the silver soldering I did. I should just replace the whole pet cock. When I rebuilt it it didn't want to stay together very well it would pop apart sometimes, I finally used screwdriver grip in the retaining ring, also it doesn't stop turning if forced either past the 12:00 or the 3:00 O Clock positions. I worry it may pop apart again with a full tank of gas! What a disaster. I wish I had never messed with it. Originally it was blocking the fuel almost totally but I had blown my air hose up the fuel line from the engine and it cleared it. But I rebuilt it anyHow. Just hope it's together right.
Yes I know I built this engine for the 1971 Bus but now it running in the 1960 Beetle, Maybe I should request it get moved to the Performance forum. It does really run sweet. It's Quite. It Pulls nice and strong. But does seem to only be able to use first 1/2 of it's throttle. That seems to be better now on the Highway though, Pulls strong past 55 mph in 3rd but really it's got good torque so shifting at 45 mph to 4th the engine takes over from there quite well.
The Zenith's make a lot of noise inside the car when I open them up. Sounds a bit out of Carb balance but it's not? Maybe it is? Temps are pretty even.

I might just do away with the Pet Cock and carry a gallon of gas in the car. Wonder if later vw tank fittings would work to eliminate it?
The Zenith's when it hits reserve seem to stumble a lot but don't completely conk out for a few blocks.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Alan Brase]

I think split bus petcocks are on the internet for sale and made by the OE manufacturer! How is that possible?
WRT Zeniths: they made 60 and 75hp DIN on porsche 1600N and 1600S engines. Maybe different venturi sizes? That's about 82hp SAE. Enough for me and more than my air cooled Vanagon. Perhaps uneven sound is valve lash? Timing advance gotta be right, also, but it really sounds like you are running out of fuel.
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Al Brase
Projects: 67 sunroof bug, 67 Porsche 912 Targa, 70 Westy
Dec 1955 Single Cab pickup WANT 15" BUS RIMS dated 8/55, thru 12/55
To New owners: 1969 doublecab, 1971 Dormobile
Vanagons:
80 P27 Westy JUL 1979, 3rd oldest known US
83 1.6TD Vanagon, 87 Wolfie Westy daily driver, swap meet home

[Danwvw]

I did go back and set the Timing and did a really tight .004" Valve setting. The carbs are just naturally noisy on the intakes! I had an 356A with them, I think if I put an A-Barth 4 tip on the Beetle it would sound like I remember that "A" Sounding.
The 1600 N 356A Zenith 32's had 24mm Venturis and the 1600 S went with 25mm ventures and the S90 I think ran 28mm ventures. I have a couple of 28's and they are hardly a Venturi almost straight!
Currently I have 25mm venturi's in it. Remember though the Porsche 356 A Cylinders were just 83mm. This VW engine has 88mm.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Alan Brase]