| Author |
Message |
Nicklastl
Samba Member
Joined: July 23, 2024
Posts: 48
Location: Denmark
|
 Posted: Fri Jul 11, 2025 11:34 am Post subject: Distributor for bus type 4 with dual webers |
 |
|
Hi guys
I'm kinda confused of what to do.
Im rebuilding my 1700 bus type 4 and i have installed a dual weber 34 ict setup, and i've been told that i can't run with my OEM Vacuum distributor.
I've been recommended a Distributor 009 with Centrifugal Advance.
But i've also seem to remember to have read somewhere, that this wouldn't work great on a bus.
What are your guys appinion?
Best regards
_________________
'73 Westfalia Project
https://www.thesamba.com/vw/forum/viewtopic.php?t=794180&highlight= |
|
| Back to top |
|
 |
boxer74
Samba Member
Joined: July 03, 2011
Posts: 857
Location: Ontario, Canada
|
| Posted: Fri Jul 11, 2025 12:21 pm Post subject: Re: Distributor for bus type 4 with dual webers |
|
|
Get a 123 ignition distributor with vacuum and run it to one of your manifolds.
_________________
74 Super
84 Westy |
|
| Back to top |
|
|
Zed999
Samba Member
Joined: March 04, 2018
Posts: 1387
Location: UK
|
| Posted: Fri Jul 11, 2025 12:41 pm Post subject: Re: Distributor for bus type 4 with dual webers |
|
|
| Use your OG distributor, it might not be perfect but it'll work better than an 009. |
|
| Back to top |
|
|
Willin
Samba Member
Joined: October 10, 2019
Posts: 257
Location: Bozeman Mt
|
| Posted: Fri Jul 11, 2025 12:41 pm Post subject: Re: Distributor for bus type 4 with dual webers |
|
|
I'm happy with the CB Magnaspark.
It's a tight fit, and you will have to change the distributor drive gear position.
There is only one position it will work on the Type 4.
I can give details if you go that direction.
_________________
73 bus. Org. 1700 with dual Weber 40 idfs, bus header with Empi qp muffler, CB magnaspark 2 " ready to run kit". |
|
| Back to top |
|
|
Nicklastl
Samba Member
Joined: July 23, 2024
Posts: 48
Location: Denmark
|
|
| Back to top |
|
|
Murt
Samba Member
Joined: October 01, 2017
Posts: 535
Location: Kent, England
|
| Posted: Fri Jul 11, 2025 11:21 pm Post subject: Re: Distributor for bus type 4 with dual webers |
|
|
Engine looks really nice. 
So it's x2 on the 123 or even the Magnaspark.
We have an old saying in the UK. "Don't spoil the ship for a ha'porth of Tar".
_________________
1966 VW Beetle ‘Jules’
1967 Kombi Splitscreen ‘Barney’
2018 VW Caddy Maxi R Line
2017 Golf GTD saloon
2008 VW EOS 2.0 TFSi |
|
| Back to top |
|
|
mikedjames
Samba Member
Joined: July 02, 2012
Posts: 3304
Location: Hamble, Hampshire, UK
|
| Posted: Fri Jul 11, 2025 11:26 pm Post subject: Re: Distributor for bus type 4 with dual webers |
|
|
The 123TUNE lets you use manifold vacuum for vacuum advance .. program it to shut vacuum advance off at 1200 rpm and then it acts similarly to having ported vacuum.
Also lets you program for weaker vacuum if thats what your carburettors do.
Or use a modern black box with vacuum advance in the timing map, this can do the same trick.
The 009 is the last thing you would want to fit on a heavy bus.
_________________
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 |
|
| Back to top |
|
|
Nicklastl
Samba Member
Joined: July 23, 2024
Posts: 48
Location: Denmark
|
|
| Back to top |
|
|
Nicklastl
Samba Member
Joined: July 23, 2024
Posts: 48
Location: Denmark
|
|
| Back to top |
|
|
Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7822
Location: Videbaek Denmark
|
| Posted: Sat Jul 12, 2025 1:23 am Post subject: Re: Distributor for bus type 4 with dual webers |
|
|
If you wanna spend a lot of money for nothing, go ahead. The ONLY 123 which is worth its money is the BT or USB. I prefer the BT.
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
|
| Back to top |
|
|
celtune
Samba Member
Joined: January 31, 2010
Posts: 32
Location: Austria
|
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23105
Location: Oklahoma City
|
| Posted: Sat Jul 12, 2025 8:21 am Post subject: Re: Distributor for bus type 4 with dual webers |
|
|
The original distributor will work. It has both vacuum and centrifugal advance.
It may need to be tweaked/adjusted but work better with no more or less work than putting a 009 in.
Will it have as much adjustability as a 123....no....but not knowing what else is in your build...compression, cam etc.....
Ray |
|
| Back to top |
|
|
Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7822
Location: Videbaek Denmark
|
| Posted: Sat Jul 12, 2025 9:48 am Post subject: Re: Distributor for bus type 4 with dual webers |
|
|
| raygreenwood wrote: |
The original distributor will work. It has both vacuum and centrifugal advance.
It may need to be tweaked/adjusted but work better with no more or less work than putting a 009 in.
Will it have as much adjustability as a 123....no....but not knowing what else is in your build...compression, cam etc.....
Ray |
I do not recall ever having seen a dual vac dizzy on a 1700/1800/2000 D jet. Is that a US thing?
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
|
| Back to top |
|
|
Zed999
Samba Member
Joined: March 04, 2018
Posts: 1387
Location: UK
|
| Posted: Sat Jul 12, 2025 10:46 am Post subject: Re: Distributor for bus type 4 with dual webers |
|
|
|
All the ICTs I've fitted have a suitable vacuum port for your original distributor. |
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23105
Location: Oklahoma City
|
| Posted: Sat Jul 12, 2025 11:31 am Post subject: Re: Distributor for bus type 4 with dual webers |
|
|
| Alstrup wrote: |
| raygreenwood wrote: |
The original distributor will work. It has both vacuum and centrifugal advance.
It may need to be tweaked/adjusted but work better with no more or less work than putting a 009 in.
Will it have as much adjustability as a 123....no....but not knowing what else is in your build...compression, cam etc.....
Ray |
I do not recall ever having seen a dual vac dizzy on a 1700/1800/2000 D jet. Is that a US thing? |
Yes. The vast majority of US D-jet systems had a dual vacuum unit. In many cases when working with a 411/412/914 with a 1.7L....the vacuum retard is a redundent nuisance.
It had an issue with dropping the idle timing too low...depending onwhat other systems it interacted with. The automatics had the vacuum throttle kicker system to allow decoupling of the torque converter when coming t oa stop with your foot off the gas.
And, both manual trans and automatic trans had a deceleration valve (vacuum actuated on manual and electronic actuated on automatic).
Every time the throttle closed and the vacuum retard came on line, it can fight with these other two systems. To get them to work took very fine adjustments all around. Add into this, the PCV valve system in the oil breather and you could get some annoying drivability issues off the line and at shift transitions as the engine got some wear at moderate miles and changed vacuum signature.
But yes....most had a dual vacuum cannister. And...some did not and some had their vacuum cannister replaced with a single by dealers (more common on 914) depending on where you were geographically.
Add into that, the vacuum advance unit only commonly found on 914 and some 412 with #917 stamped on the arm. This was an adjustable advance limiter with a set screw to limit the vacuum advance because it could re-establish at part throttle and high rpms.
But vacuum retard did have some merit depending on how you adjusted your timing. Typically, good adjustment was to set idle speed with throttle fully closed and distributor position adjusted to give you ~8-10* BTDC with vacuum retard functioning.
Then set your timing at 27 BTDC at 3500 rpm...standard....with vacuum ADVANCE disconnected.
The retard was very useful for pulling excessive "re-established" advance back on high rpm overrun/deceleration. If you set it up this way and there was enough effect....you "COULD" disconnect the deceleration valve as the function was similar.
Ray |
|
| Back to top |
|
|
|
