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Technical Pontiac help

Discussion in 'Traditional Hot Rods' started by vek, Jul 18, 2017.

  1. vek
    Joined: Sep 10, 2006
    Posts: 14

    vek
    Member
    from New Jersey

    1. installed a new msd ready to run distributor with msd wires and blaster 2 coil in pontiac 400; custom cut the wires; now getting arcing or shock from distributor when trying to set timing. Any ideas on what might be the cause?
    2. Brought engine to TDC and set #1 plug to start engine but can't get the engine to hold an idle or restart without moving timing;
    3. engine backfires when de-accelerating, checked firing order
    4. engine making tinging or rattling noise from water pump; think it is the deflector plates but looking for thoughts
     
    Last edited: Jul 18, 2017
  2. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 7,213

    Bandit Billy
    ALLIANCE MEMBER

    Start by removing the first sentence from your post before it gets the unwanted attention of the soup Nazis. Unless your 400 bird was some sort of weird pre-65 prototype, you my friend are out of compliance. No post for you!

    Second, remember they may be the same firing order as their orange cousins but poncho distributors spin counter clockwise.

    Third, ground your motor. That shock can sting a bit

    Lastly, did you change your plugs when you dropped in the MSD? If you were points style previously you have gap and heat band to address with your plugs.

    You'll get it just go back to basics and start by amending your post.
     
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  3. vek
    Joined: Sep 10, 2006
    Posts: 14

    vek
    Member
    from New Jersey

    Thanks I removed the line, I've also checked the firing order and grounded engine to the frame; grounded distributor to firewall; engine is new rebuild so new plugs, wires and distibutor
     
    Bandit Billy likes this.
  4. oj
    Joined: Jul 27, 2008
    Posts: 6,257

    oj
    Member

    If you are getting arc thru the plug wire(s) you'll have to fix that before anything else.
     
    Bandit Billy likes this.

  5. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 7,213

    Bandit Billy
    ALLIANCE MEMBER

    I had one that looked like a plasma nebula ball when you started the motor in a dark garage. My last MSD required 8 ml suppressor core wires or equivalent. Like OJ said above.
     
  6. repoman
    Joined: Jan 2, 2005
    Posts: 1,276

    repoman
    Member

    My first bet would be a cracked cap. I've seen plenty of bad ones out of the box, especially these days. Go over it carefully. Also, one or more of your ends may be short and the terminal end isn't all the way into the cap. Easy to not notice it slipped.
    2 and 3 sound like timing issues. The MSD is rtr electronically, but the curve needs tuning. On a low-compression Pontiac I would like to have around 12 initial with a total of 36-38. High compression >10:1 I would shave of 4-8 degrees.
    4. Check for pulley interference first. If it's under the cover such as the pump bearings or the divider plate I would pull the whole front cover with the water pump intact to check it out. Pontiac balancers are slip fit so it's not a big deal.
     
  7. vek
    Joined: Sep 10, 2006
    Posts: 14

    vek
    Member
    from New Jersey

    repoman - Thanks for the feedback. I've checked and re-secured the connections on the cap. Seems to be shocking through number one wire when I adjust for timing. When I made the wire I curled the spark plug wire around in the ignition cap terminal. I'm thinking this may be the reason for getting the shock. Think I have to redo the connection in the terminals.
    Got the timing set by adding a timing tape to the balancer and setting to initially 14 degrees. Used an older timing light with out electronic advance adjustment. Was told by MSD that the electronic won't show correctly. Can't believe how sensitive the timing is with this engine.
    The water pump rattle seems to have gone away after breaking in the engine but I have a exhaust leak and sounds like s valve tap. Thinking I may have to adjust valves a little while running.
     
  8. You don't adjust valves on Pontiac V8's, unless you have poly-locks or roller rockers.
     
  9. fyrffytr1
    Joined: Dec 20, 2016
    Posts: 353

    fyrffytr1
    Member

    What source are you using for the vacuum advance? I use manifold vacuum on my 67/69/71 400 motor. 69 block, 67 670 heads and 71 intake and Rochester 4bbl.
     
  10. Joe H
    Joined: Feb 10, 2008
    Posts: 973

    Joe H
    Member

    What type of wires are you using that you need to wind the wire end around a terminal? This sounds like a bad idea.
    Pontiac's often spin the out ring on well used balancers, this will throw the timing off if you didn't check and mark for true TDC using a piston stop. Best advice is turn the distributor so the engine starts ands runs on its own, then drive it under a load to see if it pings. 32-36 total should be about right depending on the fuel type and compression.
    Set the rockers to 1/2 turn past zero lash if using a poly-lock nut. Stock rocker nuts are set to 20 ft lbs, no adjustment needed and don't try to adjust them.
     
    Last edited: Aug 4, 2017
  11. vek
    Joined: Sep 10, 2006
    Posts: 14

    vek
    Member
    from New Jersey

    How do you get rid of the valve tap then?
     
  12. vek
    Joined: Sep 10, 2006
    Posts: 14

    vek
    Member
    from New Jersey

    Using the lower port on Holley street advenger carb
     
  13. vek
    Joined: Sep 10, 2006
    Posts: 14

    vek
    Member
    from New Jersey

    using MSD 8.5 wires, used a timing tape to get the initial timing set to 14 advance
     
  14. Joe H
    Joined: Feb 10, 2008
    Posts: 973

    Joe H
    Member

    If you have rockers making noise, pull the valve cover and see if you can find which one it is. Sometimes you can back off the nut and let it rattle a little then go back tight. The extra clearance may help free up the internal piston in the lifter. You could also have a rocker stud pulling out depending on the heads you have, some have press in studs, others have screw in studs.
    Summit racing sells 7/16" screw in studs with the correct base thread, and correct length. Big block Chevrolets studs will work if you cut the tops off or run valve cover spacers. Poly-locks are also easy to get from Summit, but be sure to get short ones.
    The low buck method is to replace the Pontiac nuts with small block Chevrolet 3/8" lock nuts. They are a one time set, since the locking part of the nut usually buggers up the threads. Either way will allow you to tighten the rockers. Be sure to check the under side of the rocker arm for wear and the ball end of the push rod and rocker arm, both can wear. If after that you still have noise, plan on a new camshaft.
    Does the engine have good oil pressure? There is a plug in the passenger side lifter galley at the back that gets left out when cleaning the blocks. This will reduce the oil pressure to the lifters and cause all kinds of problems. Pontiac's oil from rear main up to drivers side lifters, the crosses at the front main bearing and back down the passenger side lifter galley. If the plug is left out the rear cylinders on the passenger side get little pressure to the lifters.
     

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