News

Distributor Advance Rebuild

Discussion in '365 GT4 2+2/400/412' started by SouthJersey400i, Jan 7, 2020.

  1. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,191
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    I have two recent threads about doing the New England 1000 after doing a quickie "fix" to my distributor advance and another thread about fitting the only available distributor caps.

    While changing distributor cap it was clear that my advance mechanism was not all it should be; it seem to have two positions and nothing in between. It was very sluggish to move in any case. Note that this distributor was rebuilt by a shop in 2014 and car did maybe 14,000 miles since.

    So out came the distributor. I learned during the NE 1000 event that a good friend of mine now actually rebuilds and sets up Marelli distributors. His name is David North and he lives in North Jersey and has been active with FCA for many years. He has a 1984 400i 5-speed with 180,000+ miles! He takes it to a lot of long distance events. I contacted him just before Christmas and other than a few days of commitments he said he could turn the rebuild around in under a week.

    Here are some before and after pics and a list of the work he did. Note Dave has two 'old school' Sun Distributor machines.

    Before pics:
    Image Unavailable, Please Login Image Unavailable, Please Login
    Note the distorted plastic bushes above.

    During Rebuild:
    Image Unavailable, Please Login Image Unavailable, Please Login
    Note the replacement "bronze" (?) bushes above.

    Final Assembly: (not much to see so I left out the assembly pics.

    Here is a list of the work Dave performed.
    Image Unavailable, Please Login

    Cost of work including shipping + $512.

    I think the new metal advance guides and the lubrication pad are likely the most important item for the longevity of smooth timing advance.

    Dave provided a before and after advance curve showing how poorly mine was operating (but car running okay). Note: the RPM and advance numbers are distributor numbers; both numbers are double for the crankshaft. (I think the file is attached but I did not embed in document.) I converted the final numbers to crank RPM to use while doing timing adjustment in the car.

    As part of this project I invested in a new timing light; my previous one ended in the boat bilge and it got flooded! New one is: https://www.amazon.com/gp/product/B000EVYGV4/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1 I am very happy with it as you can read RPM and advance on same screen on back of the 'gun'.

    Once installed in car it was easy to set timing. Dave kept my paint marks in tact, so the initial advance was about 5 deg versus 8 deg target at 800 rpm idle. Te first thing I noticed was the quick response of the advance to changes in throttle both up and down. I noticed that the advance seem to run a bit below the target degrees vs RPM but that is mostly due to me laying on my back and wife adjusting throttle from above! I set the idle advance at 9 degrees. Motor is running smooth but have not done a road test yet.

    Here is how to reach Dave and please tell him that I was his referral.
    David North <davenorth73@gmail.com>
     

    Attached Files:

  2. james.colangelo

    james.colangelo Karting

    Jan 28, 2008
    212
    Detroit, MI USA
    Full Name:
    James Colangelo
    Great post and information thank you for sharing!
     
  3. Ak Jim

    Ak Jim F1 Rookie
    Rossa Subscribed Owner

    Dec 23, 2007
    4,667
    North Pole AK
    This is probably a dumb question but how do you set the timing? I mean I know how to set the timing on a normal car where you point the light down at the crank pulley and then reach over to the distributor and tweek it and then tighten up the hold down.
    How in the world do you do this when the timing marks are on the bottom of the engine and the distributor is hidden under the cowl?
     
  4. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,191
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    How to do the timing? I call it "the up down, up down"! You check timing below, clamber up to the distributor, probably on a stool, guess an adjustment and crawl back down and see how good your guess was. Two people make it a whole lot easier. To check the advance at higher RPM requires a second person sitting in the car to raise the RPM at some pre-agreed levels (it will be too loud to talk).. Before checking advance you do the idle setting. Checking the advance at higher RPM is only confirmation your advance mechanism is working correctly or not; there is no way to adjust that in the car. This is one of the great pleasures of owning a 400 series car. You lay on the floor with car on jack stands or on a lift, with two sizzling hot exhausts on either side of you and your co-worker (wife) is running the motor up to 5000 RPM!
     
    Ak Jim likes this.
  5. Ak Jim

    Ak Jim F1 Rookie
    Rossa Subscribed Owner

    Dec 23, 2007
    4,667
    North Pole AK
    Have you had a chance to drive it yet?
     
  6. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,191
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    No, I am in the middle of my annual winter R&R. Car is on lift now checking all suspension, brakes, some fluid updates, etc. I am moving right along and not had any negative surprises. It should be on the road late Feb, weather permitting. (In spite of my FChat "handle" I now live in the Finger Lakes.
    Ken
     
  7. Ak Jim

    Ak Jim F1 Rookie
    Rossa Subscribed Owner

    Dec 23, 2007
    4,667
    North Pole AK
    Let us know how it runs. This is on my to do list. Also they can make it so one distributor controls the spark and therefore the advance for both sides of the engine.
     

Share This Page