512 BBi tdc sensor | Page 2 | FerrariChat

512 BBi tdc sensor

Discussion in 'Boxers/TR/M' started by pshoejberg, Oct 14, 2020.

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  1. Newman

    Newman F1 World Champ
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    #26 Newman, Oct 19, 2020
    You need a distributor machine and each of those 4 springs / buttons are responsible for a specific rpm band. The springs are of differing length as are the sleeves for the buttons and some have shims under them. Sounds like you're on the right track and get a new steel shielded upper bearing.
     
  2. 2dinos

    2dinos F1 Rookie

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    #27 2dinos, Oct 19, 2020
    Peter, those springs are all tuned. You'll never know what went on in there, but assuming it was done with a distrib machine, there's a story for each piece. Try not to mix up the parts and how it was assembled. Those pins are not necessarily all supposed to touch at the same time. The springs work together to shape the advance curve. Recall spring constants add when in parallel, and add reciprocally when in series. Your final setting after proper spring selection is done with washer like shims typically .05 - .2mm. This really needs to be setup on a distributor machine. Again, that assembly is tuned like a - - - - (Add your favorite instrument here :)). If you purchase a brand new set of parts that are all shiny and equal length springs does not mean the advance relationship to RPM will be correct. You need to replace the broken parts and bad bearings of course. Check the movement especially at zero advance for play as this is your idle. Smooth advance through the range must be without any sticking. You'll notice corrosion etc on the precision steel parts in there. This is the maintenance aspect. The environment in there when the car is running is very harsh. Especially on a 12 cylinder distributor.

    To check the advance on the BB / BBi (No points), you'll need an external pickup setup to trigger the distributor machine light. Not too terribly complicated. The curve is in your BBi owners manual (page 74 iirc).

    How we love them so!
     
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  3. 2dinos

    2dinos F1 Rookie

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    #28 2dinos, Oct 19, 2020
    Hi Peter, I just re-read your message. I can't say for certain the distributor advance curve is causing your problem, but sounds like a good baseline to have sorted out at this stage in your project. It might be sticking as it advances. Those broken plastic bushings you discovered could be the culprit.

    Regards,
    Bruce
     
  4. pshoejberg

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    #29 pshoejberg, Oct 20, 2020
    Thanks all for the good hints gents, this community is great. I have been reading up on distributors and learned a thing...-:) One of the learning's are: If it works, don't fix it! I have fixed all the worn parts and kept the springs and shims in place as per original. It makes a lot sense when you follow the sequence of the spring loaded buttons coming into contact with the distributor cap and compare it with the ignition curve. I changed out the two "long" pins due to wear on the cones and I replaced the worn and broken nylon slide bushes with brass bushings. Now the assembly is tight again with no slip. I plan to re-install the assembly as it is and test it on the engine before I decide whether I need to put the distributor on a bench. I kind of feel tempted to build my own test bench, but that's a project for a dark winter period.

    Best, Peter

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  5. turbo-joe

    turbo-joe F1 Veteran

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    #30 turbo-joe, Oct 20, 2020
    just put the distributor in and test on the engine the advance curve. if it would be 3 ° more or less I would say keep it. very important is that on max rpm the advance is ok. if too much early igniton it could damage the pistons - but this you will hear shortly before by knocking, so as if you use fuel with too less octane.
    or when you have been riding 2 stroke bikes you will remember the noise shortly before the engine blocked :( don´t ask me why I know ;) this never happened to me with a 4-stroke engine but often I have heard this knocking when I used bad fuel or the ignition advance was to much to early or too much boost from a turbo

    don´t forget to put some grease to the brass bushings and also where the weights go on the pins and where the distributor 12 teeth rotor is rotating on the shaft

    so peter you not like a cooffee with me ;)
     
  6. pshoejberg

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    #31 pshoejberg, Oct 20, 2020
    All moving parts in the distributor are now greased up with high quality / high temp grease. It would be great to have a coffee and kick some tire's in south Germany Romano but I would prefer to bring the whole car. A trip of that length most be performed in a BBI. Last time I passed your location was in the Dino heading for the Modena Gathering and I promised myself not to repeat long distance driving in the Dino for the next few years.

    Best, Peter
     
  7. 2dinos

    2dinos F1 Rookie

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    #32 2dinos, Oct 21, 2020
    Ten years ago. I took the Boxer on a 10 hour drive. Scenery wasn't much to look at. Maybe in a couple of spots, but overall a hard drive with traffic. Sadly, I don't think the BBi improved the experience. Have since enjoyed shorter more scenic roads with calmer traffic, and the car definitely transformed the experience.

    Your point about if "it works, don't fix".... maintenance is under a separate column. Cleaning and fresh grease is a very good thing. Had you not gone in there, you wouldn't have discovered the broken plastic bushings. BTW, inspect the drum where the pins contact for divets. Lack of grease increases the wear here and this make the advance do weird things. You can carefully polish this to help. The pin heads need to slide smoothly.
     
  8. pshoejberg

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    #33 pshoejberg, Oct 21, 2020
    I have read several of your old distributor related threads lately Bruce and learned about the wear issue in the distributor drum. Luckily there were no wear at all despite the wear on the pins, so no need for any welding and grinding. Two new bearings are heading my way tomorrow so hopefully some testing late tomorrow pending good weather. 10 hours driving in a classic car in one go is also too much for my taste. I always plan for maximum 600 km/day and lots of coffee breaks. That said, comfort wise I prefer the BBi over the 308QV and the Dino. The BBi seems more quietly and the aircon actually works quite well. Maybe I'm getting old-:)

    Best, Peter
     
  9. 2dinos

    2dinos F1 Rookie

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    #34 2dinos, Oct 21, 2020
    Hi Peter,
    I can relate -> -> -> Long live air conditioning! That's another thing to watch. On my BBi, there was (and still more than I'd like) voltage drop through the A/C fan switch. Cleaning that up made the A/C appreciably more effective, but I'm reading about 1 volt + a little :rolleyes:.

    I have similar interests, V6, V8, Flat 12. My little Dino - Fiat is now fully restored and I pretty much only drive to car shows - Not super comfortable parking it, or driving it for that matter as I don't trust other drivers. I used to run the Virginia City Hillclimb in my 308 which is a 4-5 hour drive one way going ~250+ miles with 2 or 3 snack breaks. I think the 308 GTS is fairly comfortable, but when we arrived, I was just exhausted. Then 2 days running the hill followed by the drive back. I'm always impressed with the usability of the 308. Now mostly the 308 gets cleaned and waxed but when I find the time to take her out, the memories come to life. What a great great car! My kids find the BBi the most comfortable, and their favorite overall. The torque from that monster motor is a blast.

    How we love them so!
    Bruce
     
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  10. pshoejberg

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    #35 pshoejberg, Oct 25, 2020
    Her comes a short update on my fault finding endeavor. I installed the new bearings in the distributor and assembled the ignition again and started the car up with no issues. When I measured the advance with a scope light I noticed immediately that the marks on the flywheel was significant more stable both at idle and at 5000 rpm. I take that is a result of the new sliding bushings. The advance marks where spot in idle (1k) and at 5K rpm. Unfortunately the engine hesitation is still present and unchanged under acceleration, so the problem still exist. Time for the big tools...went to the attic and found my old digital oscilloscope and downloaded extensive amount of user manuals and trend curves for automotive use. This has turned into a winter project.

    Best, Peter

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  11. turbo-joe

    turbo-joe F1 Veteran

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    #36 turbo-joe, Oct 25, 2020
    good to read that the advance curve is ok at idle and at 5000 rpm. what about at 2000, 3000 and 4000 rpm?

    why winterprojekt? within short time you know what is wrong ( if it is a matter of the ignition )

    please make a photo of the pattern to see if it is only 1 or 2 cylinders or all

    you also may put the scope on each cylinder and see if the scope works fine on all. if not then you know where the problem is.

    under acceleration when driving or also when accelerating in neutral?
     
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  12. 2dinos

    2dinos F1 Rookie

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    #37 2dinos, Oct 25, 2020

    I concur. Spin that thing on a machine, then you'll know. It could be flat, than move like a switch at 3600 rev's. That's no good.
     
  13. pshoejberg

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    #38 pshoejberg, Oct 26, 2020
    Thank for input and your are all correct gents. Advance between top and bottom of the rpm range is evenly important and need to be checked. I did a rough check with a scope gun to ensure I didn't blew the engine up when test driving. Just don't have the right tools available at this very minute and that's basically why it turned into a winter project (Driving season is anyway about over here on this latitude). To answer your question Romano, the hesitation/stumbling seems only to appear when the car is being driven / accelerating in gear.

    Best, Peter
     
  14. turbo-joe

    turbo-joe F1 Veteran

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    #39 turbo-joe, Oct 26, 2020
    then I would say it is a problem of fuel - too lean.
    so try what I already have written and spray some fuel on all connections between the fuel distributors and the cylinder head.
     
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  15. pshoejberg

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    #40 pshoejberg, Dec 4, 2020
    Here is a short update regarding my engine issue with slight hesitation during acceleration. The problem is now solved. I had a sneaking suspicions that a unstable timing system could be the culprit as had some of the contributors in this thread. Based on that I went all in and changed out the MSD AL6-2 ignition to a similar but programmable version. What a transformation! Car started in first attempt, steady idle and pulling completely steady from idle and up in all gears....I'm amazed. Thanks to all for very competent and helpful input.

    Best, Peter

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  16. turbo-joe

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    #41 turbo-joe, Dec 4, 2020
    great that you found the mistake
    so the MSD AL6-2 ignition could not be programmed?
     
  17. pshoejberg

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    #42 pshoejberg, Dec 5, 2020
    Last edited: Dec 5, 2020
    There are two versions of the MSD box. The one I converted to first were the standard non programmable version. Using this box you still need to maintain the original advance system. I have now converted to the programmable version of the box where you can delete the original advance system and program your own advance curve via a PC. I have then locked out the distributor and phased the rotor to fire exactly across the distributor terminal half way through the advance curve (@21 deg). I have programmed the advance curve so it is identical with the curve in the user manual for BBi. Every modification is completely reversible in a few minutes should anyone wish to convert the ignition back to the mechanical advance system.

    This is the adventure:

    First removal of the advance weights

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    Then +- 5 degree facing of the rotor position relative to the reluctor wheel. The rotor shaft can be pressed out and turned approximately 5 deg.

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    Then locking the distributor shaft. I used a small metal plate and tag welded the rotor shaft to the distributor cup on both sides:

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    Then uploading the advance curve from the PC into the MSD box and go for a ride.

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    Next up is to fit the ignition into the Digiplex box.

    Best, Peter
     
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  18. turbo-joe

    turbo-joe F1 Veteran

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    #43 turbo-joe, Dec 5, 2020
    would it not be better instead of welding to block with screws?
     
  19. pshoejberg

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    #44 pshoejberg, Dec 5, 2020
    Last edited: Dec 5, 2020
    Screws might be a less intrusive modification admittedly but I want to ensure the rotor stays put. The whole setup is still kind of a test regime. The programmable ignition is build for max 8 cylinder engines so you have to tweak it by multiplying the rpm's with a factor of 1.5 times the actual rpm's of the twelve cylinder engine. Same goes for max amount of advance you can obtain. The box is good for 25 deg but I loose a factor 1.5 of that equals around 17 deg advance max and I need 22 deg (10 to 32 deg) to be in compliance with the original advance curve. For now I run 15 deg advance in idle and let it build up to 32 deg at 6400 rpm. You can pull out further advance if you install a map vacuum sensor and I am considering that.
    Best, Peter
     
  20. turbo-joe

    turbo-joe F1 Veteran

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    #45 turbo-joe, Dec 5, 2020
    you only can adjust the timing ( at a 8 cyl. ) from 0° to 25° or from 0° to plus/minus 25 °? because then you would have for a 12 cylinder 33 °
    if you run 15° or 10° in idle makes not much difference, only the idle rpm are a little higher. important is the advance at 6400 rpm
     
  21. pshoejberg

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    #46 pshoejberg, Dec 5, 2020
    8 cylinder: max 25 deg change, 12 cylinder = max 17 deg change. I have made a comprise now with 14 deg advance in idle and 31 deg advance at 6400 rpm. The car runs very well with this setting. See my latest curve below and note that the curve is a retard curve so all values must first be divided with 1.5 and then subtracted the 31 deg static ignition setting to give actual advance figures:

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    And you are absolutely right Romano, the idle is slightly increased.

    Best, Peter
     
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  22. pshoejberg

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    #47 pshoejberg, Dec 5, 2020
    Here is the curve expressed in excel for those who have interest.
     

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