How to make a progressive work properly on a VW engine.

[pharos]

[Alexseagull]

My engine 1904.
Didn't do any jetting yet
who can advice for the best jetting and emulsion tube to use. the bus won't go more than 75 mph?

[oprn]

Thanks for that! Good to know.
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[mikedjames]

I recently placed a thermocouple into the intake air feed above the carburettor. Using the bus thermostatic hot air feed, which cancels as manifold vacuum reduces, the idle intake air temperature from the 1973 stock bus hot air system is 90-100F. .

I also measured the temperature of the manifold below the carburettor, with a single quiet pack exhaust, where the two ends of the heat riser are symmetrical, rather than one side fed downstream into the exhaust, and I see 140-200F there, so exhaust gas is reaching it even on an EMPI progressive manifold.

It helps explain why I can jet the carburettor fairly lean.
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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[mikedjames]

[[email protected]]

[[email protected]]

You have a crappy intake.
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[Turbod16v]

ok so i put the recommended jets in, it still stumbles/lags off idle but seams smoother through out the revs.

it idles fine just gotta rev it a bit, like it has a 009 in it still, to get moving kind falls on its face from a stop.
svda is functional, tested vacuum signal and distributors armature movement with hand pump.

thinking stumble is related to the bad empi intake as it is pretty darn cold at base and stumble seams to get better if you shut it off and let it heat soak for a bit.

I'm in the toss up of keep messing with this thing (buy better intake), go to dual carbs or a single 40IDA with a GOOD heated manifold.

besides the ever present bottom stumble it is definitely running better now. my 2 aircooled buddies just keep telling me to ditch it but i would like to figure this thing out for once but at the same time I don't want to spend to much or modify to much in the process which is also making think it just isn't worth investing more into unfortunately.
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1971 westy tin top that got a 74 up pop top bolted on

[Turbod16v]

[Wildthings]

[Turbod16v]

[Wildthings]

Maybe one or two steps richer to start on the mains and go back to the smaller air correction jet on the secondaries.

Or you could try putting the 160 air get on the primary side and using the 165 on the secondary. Then initially go with one step richer in the main jet and keep with the 180 main on the secondary.

I would buy a 140 and 145 main jet for the primary main and maybe a 190 for the secondary main, but not put the 190 in until trying out the smaller air correction jet coupled with the 180 main.

Have you made sure your timing is correct?

[Turbod16v]

sorry,
it stumbles and lags lower rpm and lacks top end pull plus hill climbing power.

has better midrange after changing the jets I could.

[Wildthings]

You don't say how it is running, but if running moderately well then just take small steps in the direction you think it needs to go. Be sure to keep good records of what you do.

[Turbod16v]

Looking for advice on my setup before ordering jets. I am guilty of never tuning these things and avoiding them but now trying to figure them out!!

I popped my carb open and found it had all original jets.
I didn't know motor was a 1760 till splitting case to reseal!!
I had a old weber i was able to get one bigger jet out of (180 air)but need to get the idle ones sorted and mains but want to be sure on what to order first.

71 bus
1760 dual port motor
110 cam
flamethrower svda
generic intake heat just runs under bottom of manifold from exhaust ports.

currently it has.

Jet P S
idle 55 70 (both Still stock jets)
air 165 180 (P stock, changed S from a 160 S)
main 137 180 (P stock, changed S from a 140 S)

elevation generally under 4k, 1,3k at home.

Go with the recommended 45 55 idles, 160P air and maybe a 190S main?

Thank you!!
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1971 westy tin top that got a 74 up pop top bolted on

[Oldschoolbmx]

Thanks for posting this! I did a lot of searching on my Progressive issues I never found this page until now, luckily I found a Link to Aircooled.net and your article on the carb that was a HUGE help!!!

How do you tell if you have a real Weber? I think I do as it has a Weber sticker. It is lazer ecthed on the base plate 32/36DFEV 160 and 1206. I DO have a vacuum port.

I have a 009 distrbutor that I will switch out. Any other good choices besides the Pertonix on your page?

I have no heat. My intake is Scat, and I am confident the heater tube only goes across the bottom. I think I need your intake and linkage (my linkage sucks).

Does anyone have pics of how to route oil for pre-heat, not knowing what they were I gave away my heat risers and have no place to mount them anyway.

Once this is all taken care of will work on jetting...

[LCDR O]

This is my solution to provide clearance to my progressive carb electric choke. Cut. 48mm hole and weld a fan shroud plug. Cut and glued a round rubber piece from an old tire inner tube.

[LCDR O]

Not Bob Tomlinson's book, but good references in pdf:

http://240260280.com/Tech/Carbs/Weber/docs/Haynes/...;%20SU.pdf

https://www.lainefamily.com/images/WeberTuningManual.pdf

[LCDR O]

[oprn]

I just read the first few pages of this thread. Excellent!

I have always thought that a progressive would be a good compromise between the stock carb and all out one barrel/cylinder set up for a mild engine. My '76 Rabbit came with a Solex/Zenith progressive that had a nice feel to it once I got it sorted out. VW warrenty would not addess the drivability issues but the carbs did work if tinkered with enough.

I have been put off by the negativity surrounding the Weber progressives but John has cleared up the causes for that attitude in my mind. I have an engine rebuild in mind for my sand rail soon. Just going with a stockish 1600 DP, wanting to get a bit more zip but not interested in carbs in the rear wheel's line of fire. This will get the air cleaner out of harm's way and a nice throttle feel for those tricky situations on the hills and trails.

Thanks John!
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)