Page 150 of 214 FirstFirst ... 50100140148149150151152160200 ... LastLast
Results 1,491 to 1,500 of 2131

Thread: well, the darn thing is out

  1. #1491
    Super Moderator bmorgil's Avatar
    Join Date
    Dec 2018
    Location
    Northwestern Ohio
    Posts
    552
    Wow the coil is inside the box! Something I didn't realize about the military distributor. That would be a great way to generate some RF!

    You are an Artist no doubt. Your drawings both show about the same idea, an extra cap across the points.

  2. #1492
    Super Moderator LarrBeard's Avatar
    Join Date
    Nov 2014
    Location
    Ft. Wayne, IN
    Posts
    1,236
    The capacitor on the distributor input is isolated from the points by the inductance of the LV winding on the coil. I am pretty sure that the "condenser" is about 0.22 uF, 350 - 600 volt rating. I don't know what the "capacitor" value or rating might be, maybe someone will put one on a capacitance meter for us. It is probably rated about 200-volts or so.

  3. #1493
    Senior Member pelago's Avatar
    Join Date
    May 2016
    Location
    easter north carolina
    Posts
    1,075
    Quote Originally Posted by LarrBeard View Post
    Excuse me, Ma’am.

    May I have a large helping of crow – without feathers if you have it. Thanks to everyone who looked at my drawing of the M38A1 ignition and helped me realize that it wasn’t correct. I hope it didn’t mislead anyone.

    To reduce the radio interference in the M38A1, the engineers put ALL of the ignition stuff in a shielded box; the points, “condenser” and ignition coil. To prevent interference from crawling back out of the can onto the 24-volt vehicle wiring, they put the “capacitor” on the input to the distributor – which I believe is Wire # 12 in the harness.

    Hopefully this is a bit more correct.


    yupper, for one used schematics for the trc 75 ( a book) kinda wondered

    am not going to coat the fuel tank inside, went to three places and enough material would be 300.00 us doillars
    Last edited by pelago; 04-16-2019 at 01:09 PM.

  4. #1494
    Super Moderator gmwillys's Avatar
    Join Date
    Aug 2017
    Location
    Alabama
    Posts
    1,819
    If I had to eat any more crow, I'll grow feathers. Great breakdown explanation LarrBeard. Us non radio guys can learn something. When I first got the wagon, put a set of cheap plug wires on it. It ran good, but the AM radio would pick up the interference off the wires.

  5. #1495
    Senior Member pelago's Avatar
    Join Date
    May 2016
    Location
    easter north carolina
    Posts
    1,075
    Quote Originally Posted by gmwillys View Post
    If I had to eat any more crow, I'll grow feathers. Great breakdown explanation LarrBeard. Us non radio guys can learn something. When I first got the wagon, put a set of cheap plug wires on it. It ran good, but the AM radio would pick up the interference off the wires.
    yuppsrr had same thing with my 39 ford before i rebuilt it..

    still arguing with wire number 15, it comes out of loom and there aee two of them??? one goes into the ignition switch to power thru the light plug, the rest of the stuff, but got a hot wire after that??

  6. #1496
    Super Moderator bmorgil's Avatar
    Join Date
    Dec 2018
    Location
    Northwestern Ohio
    Posts
    552
    Quote Originally Posted by LarrBeard View Post
    The capacitor on the distributor input is isolated from the points by the inductance of the LV winding on the coil. I am pretty sure that the "condenser" is about 0.22 uF, 350 - 600 volt rating. I don't know what the "capacitor" value or rating might be, maybe someone will put one on a capacitance meter for us. It is probably rated about 200-volts or so.
    Since that is a US Government contract vehicle, aren't the specs somewhere for the capacitor? Would that info be around? There are some Multi-Meter's with a capacitance setting, you could check a known good one. Of course if you had a known good one...

    LarrBeard pointed out something. The noise capacitor is on the other side of the coil's primary winding. In stereo installs and what not it is common to put a cap on + supply lines. The bigger the better.

  7. #1497
    Super Moderator gmwillys's Avatar
    Join Date
    Aug 2017
    Location
    Alabama
    Posts
    1,819
    I'll see if I can hunt up the National Stock Number for the capacitor in the A.M.

  8. #1498
    Super Moderator LarrBeard's Avatar
    Join Date
    Nov 2014
    Location
    Ft. Wayne, IN
    Posts
    1,236
    Quote Originally Posted by gmwillys View Post
    I'll see if I can hunt up the National Stock Number for the capacitor in the A.M.
    It's good to have someone still in the business.

  9. #1499
    Senior Member pelago's Avatar
    Join Date
    May 2016
    Location
    easter north carolina
    Posts
    1,075
    have two distributors, one has a totally messed up corroded 24vdc intake to distributor the other is new, i rebuilt the distributor with the new parts i had, seems to be running fine timing at correct point.. was told by som3one i respect for his knowledge that the points if they burn up is because voltage to points too high? in a total 24vdc how can this be? and that if distributor not connected to mechanical vacuum at pump this might cause overheating in distrubotor?

  10. #1500
    Super Moderator gmwillys's Avatar
    Join Date
    Aug 2017
    Location
    Alabama
    Posts
    1,819
    On early points system, you would have a ballast resistor in between the key switch and the coil. On a 12 volt system, the resistor drops the voltage to 8 volts to help the points live longer. On a points system, in theory the small distributor caps would have a tendency to spark ark between poles, so the ballast resistor was implemented to reduce the voltage to prolong the life of the points. On the Chrysler big blocks that I had for the derby cars, I would remove the ballast resistor to send full current to the dual points distributor. With all the wide open throttle runs, I never had one failure of the points or coil. With the zoomy headers run through the hood, I could monitor how each plug was firing by the blue flame at the tip. The system was darned near bullet proof in my opinion, because these engines would really take a beating. Using GM products was much simpler. The HEI distributors were simple to wire, but they took up a lot of real-estate near the fire wall.

    Now, the 24 volt distributor is designed to take the abuse of the 24 volts coming into the coil. The coil has a resistor built in, and will help the points live for a long time.

    Doing a bit of research on the distributor in your A1, and with it's weather tight design, it does need forced air vented to the distributor to help to keep the coil cool. One line either coming off the fuel pump/vacuum pump or after the PCV valve will supply you with the negative pressure. The second line is plumbed into the air cleaner. This is why your distributor has two ports, intake and exhaust if you will.
    Attached Images Attached Images

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •