Distributor Advance Limits
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    Project 1450 supporter... Site Supporter My location RallyBob's Avatar
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    Distributor Advance Limits

    Here is a listing of US-spec distributor advance limits for 1.9 litre engines. One item worth noting is that automatic-equipped versions of these model year Opels had different advance rates (the advance occurred sooner), which was accomplished by using lighter tension springs on the mechanical advance. This was to help improve acceleration. Part numbers for the distributors for automatic-equipped cars were different than the same-year manual-equipped cars, but they were otherwise identical in operation. Except for 1975 Opels, all US-spec 1.9's had the static (idle) timing set to 0 degrees BTDC (before top dead center). Note that the engines had less and less total timing as the years progressed, in the interest of reducing exhaust emissions. Opel 1.9 litre engines tend to make the most power with a total timing figure of between 34-36 degrees.

    1968 - 32-36.5 mechanical advance
    19.5-22.5 vacuum advance
    51.5-59 degrees total

    1969 - 32-36 mechanical advance
    11.5-14.5 vacuum
    43.5-50.5 degrees total

    1970 - 32-36 mechanical advance
    11.5-14.5 vacuum
    43.5-50.5 degrees total

    1971 - 28-32 mechanical advance
    7-10 vacuum
    35-42 degrees total

    1972 - 28-32 mechanical advance
    7-10 vacuum
    35-42 degrees total

    1973 - 28-32 mechanical advance
    1-5 vacuum
    29-37 degrees total

    1974 - 28-32 mechanical advance
    1-3 vacuum
    29-35 degrees total

    1975 - 25 mechanical advance
    5 degrees static timing
    no vacuum advance unit
    30 degrees total

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    7,000 Post Club My location wrench459's Avatar
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    Stock Bosch Distributor Numbers

    Bosch distributor housing numbers

    1.1
    1966-67.................150 003
    1968......................150 006
    1969(to6/69)...........167 004
    1969(after6/69).......167 023
    1970......................167 009
    1971......................167 004

    1.5
    1968......................167 001

    1.9
    1968.............................167 001
    1969(mtrans to6/69)........167 005
    1969(atrans to6/69).........167 006
    1969(all after 6/69)..........167 024
    1970-71.........................167 007
    1972 mtrans....................176 012
    1972 atrans.....................176 011
    1973..............................176 012
    1974..............................176 012
    1975..............................170 140

    Si vis pacem, para bellum "If you want peace, prepare for war"

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    Owner of EZ2Wire.com My location GoinManta's Avatar
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    1968 - 51.5-59 degrees total

    1969 - 43.5-50.5 degrees total

    1970 - 43.5-50.5 degrees total

    1971 - 35-42 degrees total

    1972 - 35-42 degrees total

    1973 - 29-37 degrees total

    1974 - 29-35 degrees total

    1975 - (+5 static) 30 degrees total
    Anyone have the spec for the 2.0L or the 2.4L distributor.

    Quick back story. I am using a mechanical advanced 75 Distributor.

    EFI acted flaky and I replaced the AFM.. started running much better, but was still a bit tough to start and running around town I was pinging bad.

    So I checked the timing and realized I had it set by ear (hard to get a look at the mark through the EFI setup) and it was at +30 as opposed to +10 degrees..

    Which at +25, and +10 static is +35

    Now that I am back to the +35 range, it runs better but now has a slight bog.

    Mid range was better when I had it at the +30 static, but top end is smoother and no pinging.

    So wondering

    1 - Should go to a 2.0L Distributor

    2 - Go to one of the older styles to get more advance

    3 - Just add a few more degrees to the static

    4 - Maybe find a different spring to get a bit more in the distributor.

    5 - Lastly it seem counter intuitive.. but go down to +5 static and only 30 total advance
    Last edited by GoinManta; 08-12-2015 at 09:53 AM.
    CURRENT
    '71 Opel Kadett 4 Door 36D (2.0 L w/ EFI & Auto) - "Mary Ann"
    '74 Opel Manta - "Barbara"
    '05 Pontiac GTO

    In the past owned:
    '06 Pontiac GTO
    2 Bitters (#491/#439)
    '73 Commodore GS
    ATLAS ( 74 Manta w/ 2.8L LK5 )
    '73 Blue Max Manta Luxus
    & at least 20 other Opels

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    ggl
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    Quote Originally Posted by GoinManta View Post
    5 - Lastly it seem counter intuitive.. but go down to +5 static and only 30 total advance
    I don't have a definitive answer for you but here's what I've learned while messing about with my Accuspark setup

    Modern fuels burn faster than the stuff we had 40 years ago, you can get away with less total advance

    Higher compression requires less advance, reduce by 1 degree pr point you've raised the CR

    Full throttle operation requires less advance than you might think, most people run too much total advance

    During partial throttle operation more advance = more responsive engine

    As a result many owners in the TR6 community converts their vacuum retard distributors to vacuum advance distributors to improve cruising throttle response and fuel economy and there's even a kit to do this yourself

    Pinging happens before you can hear it so even at only a hint of pinging you're probably 5 degrees or more too advanced for that condition. There's no performance advance in itself to run a lot of advance, you only need whatever it takes to get you to maximum cylinder pressure at the ideal time, which for most engines is around 17 degrees ATDC, it's as simple as that really and once you accept that you just need to find that *least* amount of advance that will get you there

    Personally I would give some thought to testing a distributor with vacuum advance, assuming of course that the FI manifold has a proper ported vacuum port for this application.
    "I hate RallyBob"


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    Owner of EZ2Wire.com My location GoinManta's Avatar
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    Quote Originally Posted by ggl View Post
    I don't have a definitive answer for you but here's what I've learned while messing about with my Accuspark setup

    Modern fuels burn faster than the stuff we had 40 years ago, you can get away with less total advance

    Higher compression requires less advance, reduce by 1 degree pr point you've raised the CR

    Full throttle operation requires less advance than you might think, most people run too much total advance

    During partial throttle operation more advance = more responsive engine

    As a result many owners in the TR6 community converts their vacuum retard distributors to vacuum advance distributors to improve cruising throttle response and fuel economy and there's even a kit to do this yourself

    Pinging happens before you can hear it so even at only a hint of pinging you're probably 5 degrees or more too advanced for that condition. There's no performance advance in itself to run a lot of advance, you only need whatever it takes to get you to maximum cylinder pressure at the ideal time, which for most engines is around 17 degrees ATDC, it's as simple as that really and once you accept that you just need to find that *least* amount of advance that will get you there

    Personally I would give some thought to testing a distributor with vacuum advance, assuming of course that the FI manifold has a proper ported vacuum port for this application.
    Thanks, I have a tree that I can add to it to get it advance.

    Will look at what I have hanging around and play with them.

    Great thing is that its not too hard to replace the distributor with no fuel pump in the way.

    But sounds like 71-72 might just work perfectly..
    CURRENT
    '71 Opel Kadett 4 Door 36D (2.0 L w/ EFI & Auto) - "Mary Ann"
    '74 Opel Manta - "Barbara"
    '05 Pontiac GTO

    In the past owned:
    '06 Pontiac GTO
    2 Bitters (#491/#439)
    '73 Commodore GS
    ATLAS ( 74 Manta w/ 2.8L LK5 )
    '73 Blue Max Manta Luxus
    & at least 20 other Opels

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    ggl
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    Quote Originally Posted by GoinManta View Post
    Thanks, I have a tree that I can add to it to get it advance.

    Will look at what I have hanging around and play with them.

    Great thing is that its not too hard to replace the distributor with no fuel pump in the way.

    But sounds like 71-72 might just work perfectly..
    Looking at the numbers that's where I'd start if you want to play with vacuum as those would be "safe" numbers but today's cars actually run quite a bit of vacuum advance using the MAP (manifold air pressure ?) sensors. I've tried to simulate this through my ignition curve as my system doesn't have provisions for a MAP sensor so I'm running a bit more mid range advance as that's where you'd spend your time cruising and that seems to work out quite well

    Btw, remember that it needs to be ported vacuum in the case of our mechanical distributors and not manifold vacuum
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    Owner of EZ2Wire.com My location GoinManta's Avatar
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    Ahh.. so I need before the throttle body..

    Looks like I could tap the PCV line for that purpose ( PORT labeled C )
    Attached Images Attached Images
    CURRENT
    '71 Opel Kadett 4 Door 36D (2.0 L w/ EFI & Auto) - "Mary Ann"
    '74 Opel Manta - "Barbara"
    '05 Pontiac GTO

    In the past owned:
    '06 Pontiac GTO
    2 Bitters (#491/#439)
    '73 Commodore GS
    ATLAS ( 74 Manta w/ 2.8L LK5 )
    '73 Blue Max Manta Luxus
    & at least 20 other Opels

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    ggl
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    That looks like it could be a good spot, I honestly can't help you much there as my ZS carbs has provisions for both so I haven't needed to research this, I just know the difference.

    You can of course test the effect of this mod without actually changing the dizzy, just advance the timing 10-15 degrees or so to simulate the vacuum advance and go for a drive using only partial throttle and see how it feels. Just be careful not to go full throttle or load it up too heavily at lower revs or it will ping badly.

    I've never really understood the benefit of the vacuum advance until Wrench pointed me in the right direction a while back and as I understand it pretty much all modern cars have it, just "slightly" more advanced using sensors and computers.

    Vacuum retard on the other hand, as it was found on my emissions restricted low comp TR6, doesn't seem to have much benefit other than to reduce emissions under closed throttle conditions. I don't drive much with the throttle closed so I don' feel guilty about disabling it .....
    "I hate RallyBob"


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    7,000 Post Club My location wrench459's Avatar
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    Ported and manifold vacuum are two different animals.

    If you use manifold vacuum you'll need to decrease the initial at idle speed.
    This is great for big block Chevys,Ford,Olds to lower starter drag.

    Si vis pacem, para bellum "If you want peace, prepare for war"

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    ggl
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    Quote Originally Posted by wrench459 View Post
    Ported and manifold vacuum are two different animals.
    Geez Dan, we've already covered *that* bit .....

    What I meant was that I wouldn't know how to correctly set up a ported vacuum nipple for a vacuum advance distributor, as in does it work the exact same on a FI manifold despite the lack of a venturi, meaning, can you just hook up to any vacuum port above/ahead of the throttle plate ?

    I've haven't had to look into that since my ZS carbs have connections for both so I can run a distributor with either, or even both ..... Lucas made one of those too.

    Yes I know, Google is your friend, trust the Google
    "I hate RallyBob"


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    7,000 Post Club My location wrench459's Avatar
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    Quote Originally Posted by ggl View Post
    Geez Dan, we've already covered *that* bit .....

    What I meant was that I wouldn't know how to correctly set up a ported vacuum nipple for a vacuum advance distributor, as in does it work the exact same on a FI manifold despite the lack of a venturi, meaning, can you just hook up to any vacuum port above/ahead of the throttle plate ?
    Throttle body's don't have the choke place...so your stuck with manifold vacuum.

    Si vis pacem, para bellum "If you want peace, prepare for war"

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    ggl
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    Quote Originally Posted by wrench459 View Post
    Throttle body's don't have the choke place...so your stuck with manifold vacuum.
    Neither does many carbs, like the ZS carbs on my car, but we still have ported vacuum but I'm guessing it as something to do with the venturi ?

    If so I seem to have led Charles down the wrong path because I can't see how vacuum advance could work off of manifold vacuum
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    Owner of EZ2Wire.com My location GoinManta's Avatar
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    Quote Originally Posted by ggl View Post
    Neither does many carbs, like the ZS carbs on my car, but we still have ported vacuum but I'm guessing it as something to do with the venturi ?

    If so I seem to have led Charles down the wrong path because I can't see how vacuum advance could work off of manifold vacuum
    I guess the key would be do I get enough vacuum OR is it that I would get too much vacuum ? or the vacuum would be at the wrong place wrong time..?

    I guess I could still play with the other distributors.. but no vacuum just run off their slightly elevated mechanical advance.

    As right now I have 25 max with the 75 distributor.. and if I went to one of the others (I Found 4 distributors in my garage cleanup.. )

    I believe if I leave the pods connected but don't hook up the vacuum they will run like the 75 as a mechanical only distributor. I would have two options.. Pre 71 which is 32-36 or 71-74 which is 28-32. I assume the variance is in the springs and why you replace one of the springs in the 75 and it becomes a 25 with no variance.

    So right now I am at +10 Static and a +25 Mechanical or 35 total.

    Its loosing a bit in the middle and off the line.. so I could go to

    +10 Static and a 71-74 (28-32) That gets me 38-42 range..

    Long story short.. I have options to play with.

    What I would love to know is what the specs of the 2.0L and 2.4L Distributors are.. As I have a 2.0LE injection and a 2.4L Cam.. so I might want to emulate their distributor specs for the smoothest and best performance.
    CURRENT
    '71 Opel Kadett 4 Door 36D (2.0 L w/ EFI & Auto) - "Mary Ann"
    '74 Opel Manta - "Barbara"
    '05 Pontiac GTO

    In the past owned:
    '06 Pontiac GTO
    2 Bitters (#491/#439)
    '73 Commodore GS
    ATLAS ( 74 Manta w/ 2.8L LK5 )
    '73 Blue Max Manta Luxus
    & at least 20 other Opels

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    Member My location guyopel's Avatar
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    Have you had any luck talking to Juan about his dist. products? This could give you something to work with maybe. HTH
    John
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    Quote Originally Posted by GoinManta View Post
    I guess the key would be do I get enough vacuum OR is it that I would get too much vacuum ? or the vacuum would be at the wrong place wrong time..?
    The last one, wrong time. Manifold vacuum is high during closed throttle operations and drops as soon as you open the throttle plate. Ideal for vacuum retard which reduced emissions but worthless for partial throttle operations.

    It works in a computerized ignition system of course since the computer knows all the variables, ported vacuum is the "analogue" version of this. It may still work to a certain degree of course but seeing as Opel dropped the vacuum advance as soon as they moved to FI ..... chances are it won't.

    Time to install a MAP sensor Charles and give Juan a call as suggested above, go all computerized
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    Owner of EZ2Wire.com My location GoinManta's Avatar
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    Quote Originally Posted by ggl View Post
    The last one, wrong time. Manifold vacuum is high during closed throttle operations and drops as soon as you open the throttle plate. Ideal for vacuum retard which reduced emissions but worthless for partial throttle operations.

    It works in a computerized ignition system of course since the computer knows all the variables, ported vacuum is the "analogue" version of this. It may still work to a certain degree of course but seeing as Opel dropped the vacuum advance as soon as they moved to FI ..... chances are it won't.

    Time to install a MAP sensor Charles and give Juan a call as suggested above, go all computerized
    I may.. I THINK looking at the BMW setup I have, they may have included one in their LU setup.. Hoping another 318 shows up shortly to the pick-a-part.. Want to get another Opel setup with it too.
    CURRENT
    '71 Opel Kadett 4 Door 36D (2.0 L w/ EFI & Auto) - "Mary Ann"
    '74 Opel Manta - "Barbara"
    '05 Pontiac GTO

    In the past owned:
    '06 Pontiac GTO
    2 Bitters (#491/#439)
    '73 Commodore GS
    ATLAS ( 74 Manta w/ 2.8L LK5 )
    '73 Blue Max Manta Luxus
    & at least 20 other Opels

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    Wedge head's have a very predictable spark curve NO matter which STOCK camshaft is being used!
    Once you get past that you can move forward.
    Last edited by hrcollinsjr; 08-14-2015 at 07:31 AM.

    Si vis pacem, para bellum "If you want peace, prepare for war"

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    20S Bosch 0231 170 188(points)0237020042(electronic:
    Initial timing: 5deg/800rpm(no vac)
    Mechanical advance: 5-12deg/1500rpm, 14-21/2500rpm, total:22-28/4000rpm
    Vacuum advance(only):12-17deg begin 120mbar end 265mbar.

    20E Bosch 0231170235(points)0237020040(electronic)
    Initial timing: 10deg/850rpm(no vac)
    Mechanical advance: 5-13deg/1500rpm, 10-17deg/2000rpm, total:15-21/3000rpm
    Vacuum advance(only):12-17deg begin 120mbar end 265mbar

    AFAIK, 2.4 is microprocessor controlled ignition(digital map). Distributor is just a solid shaft that sends HT current to each wire(like the Mercedes M103 engine).
    HTH.
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    Owner of EZ2Wire.com My location GoinManta's Avatar
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    Thanks, is the 2.4L system separate of EFI or incorporated into it..? I.e. Could it be run stand alone.

    Anyway, listening to ggl, I did something what would seem counterintuitive.

    I retarded the Kadett to +5 from +10, and Ill be damned. Just what she needed even less advance. So I'm at only +30 total. Might drop it to TDC later and see if that helps or hurt.
    Last edited by GoinManta; 08-15-2015 at 06:23 PM.
    CURRENT
    '71 Opel Kadett 4 Door 36D (2.0 L w/ EFI & Auto) - "Mary Ann"
    '74 Opel Manta - "Barbara"
    '05 Pontiac GTO

    In the past owned:
    '06 Pontiac GTO
    2 Bitters (#491/#439)
    '73 Commodore GS
    ATLAS ( 74 Manta w/ 2.8L LK5 )
    '73 Blue Max Manta Luxus
    & at least 20 other Opels

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    Quote Originally Posted by GoinManta View Post
    Anyway, listening to ggl, I did something what would seem counterintuitive.

    I retarded the Kadett to +5 from +10, and Ill be damned. Just what she needed even less advance. So I'm at only +30 total. Might drop it to TDC later and see if that helps or hurt.
    Awesome, I'll share some of the appreciation with Wrench as it was a couple of his "weird" posts that clued me into the "less is more" when it comes to ignition curves. My TR6 is currently running about 7 degrees less total advance than the factory specs and it's happier than ever and revving more freely.

    As for the FI on the 2.4 I found this post from RB on the subject http://www.opelgt.com/forums/engine-...tml#post135584
    Last edited by ggl; 08-15-2015 at 06:29 PM.
    "I hate RallyBob"


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