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Distributor Number & timing specs.

Discussion in 'Bay Tech Clinic' started by Cooper62, May 19, 2017.

  1. Cooper62

    Cooper62 Member

    Messages:
    59
    Location:
    Perth
    I have a 1600 dual port in my 75 bay which is running a SVDA distributor.

    The VW number on the dizzy is 043 905 205B, and the Bosch number on it is 0 231 168 001.

    I am having a mongrel of a time trying to find the correct timing information for this dizzy...I have set the timing to 32 degrees BTDC at 3000 rpm, but when it drops back to idle it is reading TDC.


    I have checked heaps and heaps of web pages trying to find the correct settings, and everything is so bloody contradictory....I have even rung Bosch but they had no info on it.

    Some sites say all SVDA dizzys on 1600's should be timed at 7.5 degrees BTDC, but if I do that my advance curve goes way too high, it pings like crazy and runs hot.....Other sites say it should be timed at 5 degrees ATDC.

    Anyone got the correct specs?
     
  2. oldman

    oldman Super Moderator Staff Member

    Messages:
    11,003
    Location:
    Avalon Beach NSW
    Have you checked John Muir's or Bentley for info.?
    Both are my go-to reference manuals for this sort of thing....
    Cheers,
    Mark
     
  3. Cooper62

    Cooper62 Member

    Messages:
    59
    Location:
    Perth
    Thanks for the reply Mark. I should have mentioned in my original post that I have both the Muir & Bentley manuals but I couldn't find what I was after.

    I found a couple of good sites with a large range of Bosch & VW dizzy numbers.. My dizzy is listed on site as a "non US 70's type 2 1.6"...Although this link doesn't provide settings, my dizzy is grouped with a couple of other models which I have found the specs for on the oldvolks web page....They again specify 7.5 degrees BTDC....

    https://www.thesamba.com/vw/archives/manuals/Bosch_Tune_Up_Parts/Bosch_Tune_Up_Parts.pdf

    http://www.oldvolkshome.com/ignition.htm#A1974AFD

    I'll have another play with it tomorrow.
     
  4. oldman

    oldman Super Moderator Staff Member

    Messages:
    11,003
    Location:
    Avalon Beach NSW
    Andrew- 1500king- on here would know, for sure.
    Might be worth contacting him...
    Cheers,
    Mark
     
  5. twincabay

    twincabay Active Member

    Messages:
    559
    Location:
    port maquarie
    I have the same setup x 2 both set at 7.5 static , both run great and dont get hot.
    Whats the quality of your timing light like? Hows it run at 5 ? if it doesnt ping and runs nice I think you have your own answer.
    How well the engine runs then is up to a number of factors especially good ignition ( coil leads ) and well dialed in accelerator pump. Trial and error worked for me small adjust test drive re adjust. Mitch
     
  6. cbus

    cbus Well-Known Member

    Messages:
    13,570
    Location:
    sunshine coast
    I assume engine has been running prev and no issues?
    Have you checked timing previously?

    Checks.
    How many notched does the pulley have.?
    You are timing to case centre line?
    Vacuum line off when checking mechanical advance @ 3500 rpm?

    Check range of mechanical advance on dissy . (vac off)

    They can vary but 0 to 32 is well out of normal range for mechanical.
     
  7. Cooper62

    Cooper62 Member

    Messages:
    59
    Location:
    Perth
    Motor was completely rebuilt about 1 year ago and has run well up until now.

    I have an aftermarket pulley with graduated degree marks. Original pulley had TDC on the front lip, and 5 BDTC & 7.5 BTDC marks on the rear lip of the pulley.

    Setting centrifugal timing to 30 degrees at 3,000rpm results in full timing (with vacuum reconnected) of 42 degrees at 3,500rpm.

    Valve clearances are correct and dwell angle is 47 degrees....Have also tried retuning carby and adjusting accelerator pump to several various positions.
     
  8. 1500king

    1500king Well-Known Member

    Messages:
    1,683
    Location:
    Adelaide, SA
    That is the correct distributor.

    Timing specs are 7.5 degrees BTDC @850rpm, with vac line disconnected from the distributor(and blocked so no vac leak). Should be a notch in the crank pulley(inner) about 13mm to the right of the TDC dimple on the outer lip.

    They achieve full mechanical advance at 3800rpm (21-24 degrees) with 10-12 degrees of vacuum advance on top(only during low load conditions, controlled by the throttle plate on the carb).
     
    oldman and Cooper62 like this.
  9. merrymike

    merrymike New Member

    Messages:
    28
    Location:
    Melbourne, Australia
    Sounds like you need to re-curve your dizzy - maybe get the stop adjusted to bring back maximum advance on it to 21 - 24 degrees.

    If your dizzy is shot I recommend the 123-TUNE dizzy for VWs - get it programmed to meet the curve spec for your dizzy rather than trying to make an off the shelf one not exactly right for your engine work. One of the issues about aftermarket dizzies are they are curved for beetles not buses and the max advance comes in a lot later. They are expensive but I can't speak highly enough of them. You'll also have electronic, computer controlled ignition.
     
  10. Cooper62

    Cooper62 Member

    Messages:
    59
    Location:
    Perth
    I have rechecked and reset everything on my bus and it is running pretty sweet now.

    I set the distributor at the point where centrifugal advance maxed out.

    Although it wasn't leaking, I replaced the vacuum hose that runs from the distributor to the carby. Rechecked points setting and dwell angle to 47 degrees.

    I also removed and completely stripped & cleaned the carby (Solex 34 Pict 3), and whilst doing that I noticed that the accelerator pump linkage had some wear which meant it was not delivering petrol immediately when activated. I slightly adjusted the bell adjusting cam to compensate.

    Also replaced and reset auto choke mechanism.

    Went for a test drive and it still had a very slight ping under load, so retarded the timing only by a degree or two. Went for another drive and it all seems great now.

    Thanks to everyone for your help and advice.
     

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