Dwell setting to no start
 

Hi. My 1970t was running great, new MSD Street Fire installed with points. I've set the dwell, checked it, set the dwell, checked it, then no start? I got a spark to the distributor body when checking the dwell by mistake but no fuses are out. Why is it not starting? Could it be that I set the points twice without setting the timing in between? Try moving distributor to get a start? Too late here now to be starting cars will try in the morning but any ideas/suggestions before I try? Cheers

Try gently spreading the points so you can slide a trimmed Q-Tip, damp with MEK/Lacquer thinner, between the contacts. I've seen no-starts occur if a tiny amount of distributor cam grease contaminates the points. I hope that you didn't fry your new electronics by shorting something out!

Double check your wiring to the points make sure the insulator (where the wire connects to the post passes through the distributor housing) is installed correctly and not shorting out.

Changing the dwell changes the timing.
Set dwell then set timing and see how it goes.

Any chance the distributor is 180 degrees out..??

I'm also hoping I didn't fry anything. The engine didn't stop when it sparked, it just wouldn't re-start after the last dwell was only about 20 degrees. I opened them up again, no start.

Points are probably not in contact with the dist shaft. Loosen the dwell angle screw, move it in and then see if it starts. If your dizzy is old like mine you might have a lot of play in the shaft.

not enough to keep it from running.

have you checked for spark

the points are nothing more than a ground switch. when the ground is removed, points open, the CD unit fires.
as far as the points gap, they just need to open and close. the dwell is not critical. the 10yrs I had my 77s I NEVER set the points with anything other than eyeballing them.
you can bypass the points and wiring by grounding the points wire from the CD unit and removing it. there are instructions at MSD for TSing.

if the dist is 180 out you will usually get a loud backfire, but still check it.
(have you been removing or have you removed the dist since it last ran)

check the wiring to the coil. mine ran with the wires backwards on the coil but that does not mean they all will. check grounding.

this is a dumb one but I went thru a phase of this, did you put the rotor back on.

just to be clear:
was it running THEN you put the MSD on and it will not start or was it running with the MSD and you started messing with the dwell?
what else have you done to it

No, it was starting just fine before I moved the points for dwell. Thanks though

Yes it was running with the MSD installed then I attempted to set the dwell, then it wouldn't start.

Rotor button on.

Distributor has not been out.

Will check for spark in the morning.

Cheers

did the wire from the points come off of the connection inside the dist

are the points completely opening and completely closing.

I would pull the connector on the MSD with the dist set so the points are closed make sure you get a ground from the connector to the dist.

are you getting power to the MSD.
did you bump one of the fuses on the relay panel, (cant remember if power for the CD goes thru them).

Not sure what you mean about pulling the connector on the MSD to bypass the points. What would this achieve or prove?

Points opening and closing turning by hand.

Fuses look ok.

What I don't understand is if I shorted something that caused the MSD to fail, why didn't it immediately stop the engine? Surely this would have happened. Same with the coil, if it fails while the engine is running the engine would stop wouldn't it? Why just not start again? Loosing sleep!

Check the green shielded wire, messing with it lets the demons under the insulation.

Coming from where?

Just repeating what I say below but would the engine not stop if the MSD or coil had a fault while it was running? It just would not re-start.

Primary wire to dizzy, that shielded sucker has caused woes beyond belief. You were messing with the points and wiring.

Ok, so after not sleeping and waking at 4.30am to take out the points, clean them, eye ball the gap, then waiting until a reasonable hour to attempt to start it, it started. WAHOO!!!! I will not be adjusting the dwell again, just the timing to do after work...

I had the same problem when I tried to set my dwell. I forget what the exact condition was but it can only be one of two, either the points never opened or never closed. Easy to check with a ohm meter, put one side to ground and the other to your points wire, with key off rotate the engine by hand and check to see that they open and close. Set them with a feeler gauge and forget about it, consensus is dwell isn't important on a MSD.

Good job! And, yes, if the points were contaminated but the engine was running, once the car was shut down the car went into a no-start condition, that is possible.