Power Timing your Buick V8

Discussion in 'Buick FAQ' started by LARRY70GS, Jan 2, 2005.

  1. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    :D:DOK, make it "First Time at the track with my Buick":D:D Just start another thread in The Bench.
     
  2. MarkusM

    MarkusM Active Member

    40 pages for ignition issues and information, wow.
    Larry you wrote that Buicks have fast burn heads or most of them.
    Did you know if the 300 V8 had them too?
    I'm at a learning stage at Buick 300 engines. I know SBC's, BBC's same on Fords, also Flatheads Ford.
    I read a lot about the 300 engines the last 2 weeks and know that there is nearly no aftermarket for these engines.
    On our engine there is the stock distributor, I want change to a pointless version with all the adjustable stuff my MSD has on my SBC (I changed the non adjustable vacuum can to one adjustable from ACCEL and add 8° of vac advance, also recurved with changing the springs etc.). I found some distributor that will fit.
     
  3. telriv

    telriv Well-Known Member

    You have options with your stock distributor like adjustable vacuum advance, advance limiter plates, one wire electronic ignition conversions, etc. ALL of which I sell.

    Tom T.
     
  4. MarkusM

    MarkusM Active Member

  5. telriv

    telriv Well-Known Member

    Yes I do. send me a PM

    Tom T.
     
  6. MrSony

    MrSony Well-Known Member

    Would the two silver springs make the advance come in at 2200 on any distributor, or only the Buick HEIs, or only your distributor?
     
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    No, those RPM are approximate. Weights vary, so you must check. Easy to do with a light and tachometer.
     
  8. MrSony

    MrSony Well-Known Member

    Two silver gave me about 2600rpm all in with a TA HEI. I have a silver and a yellow and it's around 2100 all in. Still have to adjust the vacuum advance, but it's snowing right now so i really don't want to bother with it. The crane kit is a good kit, I like it. Question: you only have to use the limiter plate if it puts too much vacuum advance in, right? What amount of advance does it put out uninhibited? I didn't find that number in the instructions.
     
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    A lot, at least 20* I would say. If all your mechanical advance is in by 2100, hook up your vacuum advance, rev it to 2100, and use the dial back light to see what your total is. Then subtract. With all your advance in that early, your vacuum advance may put you at mid 50's, and that can frequently cause part throttle ping or surging. In General, mid 40's works best, so 8-12* is what you want.

    The limiter plate is used to reduce the amount of vacuum advance. If you follow the directions, they tell you to attach the plate on end mounting screw of the canister. Then when you rotate the plate, it pushes the link further into the canister. This is undesirable for 2 reasons. One, it retards your initial timing (2* per tooth), and two, it preloads the spring inside the canister.

    A better way to use the plate is to drill and tap a hole in the canister arm AHEAD of the link. That way, the plate limits the distance the link can move, and therefore limits the amount of advance the canister can deliver. You can adjust the spring independently with the allen key through the vacuum port.

    Crane3.jpg Crane4.jpg
     
    MrSony likes this.
  10. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Interestingly enough, the instructions I found don't mention the limiter plate at all, but just an adjustment through the vacuum port. I am wondering if the Crane units are now like the Acell adjustable vacuum advance canisters. The allen wrench adjusts amount and rate of vacuum advance at the same time.
     

    Attached Files:

  11. MrSony

    MrSony Well-Known Member

    So if I install the plate as you describe... Would I need to mess with the allen adjustment at all? It says to turn it all the way clockwise... Is that setting max vac advance? I assume so because it then mentions drive around and back it off two turns if it knocks. I have it attatched to ported vacuum with the adjustment screw all the way in. Drove around and didn't notice any lnocking longing or surging. With the ta HEI my timing must have been around 52*. I have 9.5:1 with a crower level 3... Maybe thats why it can tolerate so much? I'll have to double check it with a light to be sure its working.
     
  12. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    See post 790 above. Did the limiter plate come with your kit? I ask because the new instructions don’t mention the plate. Do your instructions mention it or are they like the ones I attached?

    Previous kits used the plate to limit the AMOUNT of vacuum advance. The Allen key adjustment controlled the RATE. Varying the spring preload controls when the vacuum advance comes in (vacuum level) and how fast it goes away when you punch it.

    I’m not sure if the current Crane canisters have the adjustment all in one via the Allen key like the Acell units did. You should be able to tell with a vacuum gauge and timing light.
     
  13. MrSony

    MrSony Well-Known Member

    My kit did come with the plate and directions on how to use it, must be an older kit. Bought it from summit.
     
  14. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    OK, then you have everything you need to set it up. If you send me an e mail to the address in my signature, I’ll send you some more pictures on how to mount the plate.
     
    Last edited: Jan 14, 2019
    MrSony likes this.
  15. JStov

    JStov Well-Known Member

    Hi Larry I installed a new Buick hei aftermarket distributor and did your power timing procedure and ended up recording the timing at 40 it does go back to the initial point everytime. Idles good with a little sputtering pop out of the tail pipe every now and then not loud) I installed a oem intake and rebuilt Quadra jet 800cfm and took it out for a spin after the install and power timing and it just doesn’t have a lot of power I don’t even think the secondaries are opening. Could this be because of the timing? Btw I have not replaced the springs or bushings should I?
     
  16. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I don’t know what aftermarket HEI you used so it is difficult to answer your questions. Did you disconnect the vacuum advance? If you did, 40* is too much. Without replacing the springs, it isn’t known if you maxed out your mechanical timing. That is important, it might be more than 40*. Make sure the throttle blades are wide open when the gas pedal is floored, it may not be.
     
  17. JStov

    JStov Well-Known Member

    Thanka for the reply, its a street performance distributor ive emclosed a pic. Yes I did disconnect and plug the vacuum adv. I did everthing step by step x2 and when I recorded it was at 40. Yea the throttle blades are barely opening in wot. Im going to check put my choke and possible adj the throttle blades the spring tension the seem to be ok but maybe need to be loossened.
     
  18. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    It is VERY IMPORTANT that you determine that the centrifugal weights in the distributor have reached their full travel out. If you do not, advance will be added at higher RPM. That is the REASON to use the lightest springs to set the total advance (initial + mechanical). The lighter springs let the weights extend to their full travel at a much lower RPM so that you can be sure that your advance is at a maximum and will not advance beyond that. After you have set the total, you can then use the springs that get all your advance in at 2500-3000 RPM.

    If you have measured the total advance at 40* without VA, that is too much. It means you must reduce your initial timing by the amount necessary to get your total advance to 32-34*. Lots of HEI distributors have too much mechanical advance built into them. You cannot easily adjust that, it is what it is for the distributor you have. This can limit the amount of initial advance you can run without over advancing at higher RPM.

    If your Q-jet is not opening fully when the gas pedal is floored, it is one of two things. Either the choke lock out tab is preventing the secondary blades from opening, OR, your throttle cable/bracket is wrong.
     
  19. JStov

    JStov Well-Known Member

    Ok I didnt the springs at all when doing this, I will purchase the parts and and use the lightest springs and set redo hopefully it gets me to that sweet number and I'll check both of those things the choke lockout and throttle linkage, might you have a youtube video on this for newbies like me lol
     
  20. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    It would be very difficult to make a video with good clarity, I'd certainly need more than 2 hands I would think. Having said that, guys make this into Rocket Science and it just isn't.:D If I showed you how to do this in person, you would probably be kicking yourself for weeks. There is a word document attached to the first post. If you haven't downloaded it, do so. It explains how to use a dial back light to do this.
     

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