Need help with points distributor. 73' 620

[wilfvelez]

Before this starts out of control. Yes, I'm looking into getting a D4K Dizzy. Yes I know points suck. Now that I have that out of the way. I need help with this 620. I got it a week ago and after going through the truck I m ready to fire up and bang no spark. I don't remember how the distributor should look inside since the last time I worked on one with my dad was over 30 years ago. I can tell something is not right. There was only one wire connected to the distributor. It was connected to the condenser and the points. I have power to the coil but with the switch on there is no power to the one wire connected to the distributor. It also look like someone messed with the timing as well. I would like to hear the engine running before I get into brakes and distributor upgrades. I have a service manual but it doesn't get me any details as of which wires should have power where the grounds go etc. I need a picture of what right looks like and some wiring guidance to the distributor. My guess is that some wires were crossed somewhere. Thanks in advance for the help guys.

[datzenmike]

Well find the ballast resistor.

 

There will be a Black/White stripe wire to one side. A Black/White stripe wire from the other side to the + Positive side of the coil. This is from the ignition switch and is hot when the key is in the ON and the START position. With the key ON it will read battery on the in side of the ballast and somewhat less on the coil side.

 

There will also be a Black/Red stripe wire on the + Positive side of the coil. This is hot only in the START position of the ignition switch.

 

In operation there is 12 volts to the coil during START from the Black/Red wire, but when the key returns to the ON position power to the coil has to go through the ballast resistor to drop it to about 8? volts. Without the ballast resistor the points would burn out in about 50 miles.

 

There are two wires on the - Negative side of the coil but explaining the dual points is.... pointless. All you need to know is the Black wire goes to the points in the distributor. If you find the Blue/White wire just pull it off the coil and ignore it for now.

 

 

Points. Set the points rub block on one of the cam lobes and adjust the points gap to about 0.022". As the distributor turns they will close and open on the top of the four cam lobes.

 

 

Set the engine to TDC compression stroke on the number one piston. Take distributor cap off. The rotoe should be pointing to the number one spark plug wire above it on the cap. Firing order is 1 3 4 2 in a counter clockwise direction. Check the wires go all the way to the correct plugs. If you have gas in it, it should start. Once started set the timing to 5 degrees BeforeTDC

[wilfvelez]

Thanks that makes lots of sense this one only have one point. I will trace these wires next time and give a feed back.

[banzai510(hainz)]

look up YOUTUBE on points adjustment.

 

key on you will get 12volts at the blk wht wire at the ballast. then current goes thru and get about 6 volts (if no voltage then ballast maybe broke).  if NO 12volts at the Blkwht wire either key switch loose fuse pop or wire off at the ballast.

 

 

EZ ck is pull the center coil wire from dist cap and place near ground try to start and ck for spark. If not most like points is not opening or constanly grounded or condenser shorted

 

Now if you have spark then ck the fuel valave lash and timming

 

olddatsuns.com has everything in the tech section

[wilfvelez]

Thanks guys, cleaned everything put new points and condenser. Gauge them to 0.022 and she started the first try. Ran her for good 20 minutes. Brakes are completely busted from the booster on down, but that and the floor pans will be in another thread.