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mturner7 Samba Member
Joined: April 04, 2022 Posts: 20 Location: Northern CA
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Posted: Thu Jul 28, 2022 2:49 pm Post subject: My Weber IDF 40's don't have a vacuum port |
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Hi Everyone, This vacuum connection to the weber carburetors has been talked about 100 times, but I need to address it again.
CAR/Engine:
1) Porsche 914-4: 1975 1.8L big bore build, dual IDF 40 Carbs
2) I have Weber 40 IDF 19 's with no vacuum port
3) I have a Pertronix 1 SVDA Distributor, 12 VOLT with electronic points
4) I have two sets of intake manifolds
- One set has a port already drilled and plugged see photo
- The other set does not have a hole/port
5) Since my new Pertronix 1 SVDA Distributor, 12 VOLT has the combination of centrifugal and vacuum advance installed, Can I just remove the plugs in the intake manifold and add the vacuum line with a "T" back to the distributor? Someone said that the vacuum connection has to be above the butterflies?
7) That's the way it is connected in my 1974 Porsche 914-4 2.0L car, except the car has dual weber 44 IDF's with a vacuum port on the bottom of the carb itself.
Please help, I'm in the middle of my build and coming close to installing the carbs, intake's, and distributor.
p.s.: I have two sets of intake manifolds, the holes that connect to the carbs are different on the two sets.
- 48mm for the short ones
- 40mm for the long ones
The 48mm ones were on the engine with the weber 40 IDF's
The 40mm ones were on a car with Weber 44 IDF's
The 48mm ones have the port driller and tapped.
Will it matter which one I use>? 40mm hole or 48mm hole? |
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Starbucket Samba Member
Joined: April 30, 2007 Posts: 4032 Location: WA
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Posted: Sat Jul 30, 2022 2:56 pm Post subject: Re: My Weber IDF 40's don't have a vacuum port |
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No photo but remove the plugs and put a barbed nipple and connect both carbs with a 'T' to the dist. so you don't get pulsing. |
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mturner7 Samba Member
Joined: April 04, 2022 Posts: 20 Location: Northern CA
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Posted: Sat Jul 30, 2022 3:20 pm Post subject: Re: My Weber IDF 40's don't have a vacuum port |
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You have to select the "Gallery" Button to see the photo
Last edited by mturner7 on Sun Jul 31, 2022 1:07 pm; edited 1 time in total |
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Starbucket Samba Member
Joined: April 30, 2007 Posts: 4032 Location: WA
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Posted: Sun Jul 31, 2022 1:00 pm Post subject: Re: My Weber IDF 40's don't have a vacuum port |
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You will want to use 40s with 40s so you will have a smooth flow through the heads you will get turbulence with the 48s. Just drill and tap the 40s for vacuum fittings. |
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mturner7 Samba Member
Joined: April 04, 2022 Posts: 20 Location: Northern CA
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Posted: Fri Aug 05, 2022 11:33 am Post subject: Re: My Weber IDF 40's don't have a vacuum port |
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Starbucket wrote: |
You will want to use 40s with 40s so you will have a smooth flow through the heads you will get turbulence with the 48s. Just drill and tap the 40s for vacuum fittings. |
Thx Starbucket, that's what I figured, but this combo (40mm carb and 48mm Intake) came off a running 1972 Porsche 914 1.7L. Weird that they would have done that, unless they had a set of 48 Webers on there at some point and never changed out the intakes.
Thx -Monte |
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mturner7 Samba Member
Joined: April 04, 2022 Posts: 20 Location: Northern CA
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Posted: Fri Aug 05, 2022 11:39 am Post subject: Re: My Weber IDF 40's don't have a vacuum port |
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I Have an update from AirCooled.net:
Problem Solved!
================================================
Monte,
Just plug the port on the SVDA Distributor, and time it to 8 BTDC at idle.
OR put a port in an intake, and time it to 8 BTDC at idle HOSE OFF (then connect hose after timing, and then sync carbs).
John
ACN
================================================
Customer Service, Aircooled.Net <[email protected]>
Monte Wrote to Aircooled.Net:
I purchased the "Pertronix 1 SVDA" Distributor, 12 VOLT (Flamethrower I Points replacement device installed), D186504 from you guys. I Haven’t installed it or taken it out of the box at this time.
It turned out the weber carburetors I’m using are the early model IDF 40’s, without a vacuum port.
1) Can I just plug the vacuum port on the distributor and call it good?
2) Drill out the carburetors and add a vacuum port?
3) Get a different distributor?
4) Get different carburetors?
Someone online said I have to have the vacuum port above the butterfly’s, not below them or in the intake manifold. Can you shed some light on that?
Thank You -Monte |
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SPTom Samba Member
Joined: December 30, 2021 Posts: 26 Location: São José dos Campos --SP Brasil
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Posted: Mon Nov 21, 2022 3:27 pm Post subject: Re: My Weber IDF 40's don't have a vacuum port |
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Hi Monte,
I'm in a similar boat as I got some old Italian IDF 40s but no vacuum advance. Which way did you end up going? Plugging or porting? How were the results?
Thanks,
T |
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mturner7 Samba Member
Joined: April 04, 2022 Posts: 20 Location: Northern CA
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Posted: Tue Nov 22, 2022 1:16 pm Post subject: Re: My Weber IDF 40's don't have a vacuum port |
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SPTom wrote: |
Hi Monte,
I'm in a similar boat as I got some old Italian IDF 40s but no vacuum advance. Which way did you end up going? Plugging or porting? How were the results?
Thanks,
T |
Hey I went with the plug on the vacuum port on the distributor, works great. Monte |
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