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fresh motor no spark, help!

Posted By: SS/ Demon

fresh motor no spark, help! - 08/18/15 03:11 AM

I just put a fresh motor in my 71 Dodge Demon. It is a 340 that is 13.5:1 compression solid roller race motor. I went to start it for the first time in the car and it slowly cranks over with no spark. The ignition consists of a digital MSD AL6 powering a Mallory super mag 2 coil with a Mopar direct connection tach drive distributor. The ignition worked previously with a different distributor (since sold) and the tach drive came out of a working running vehicle. So I go to crank the car and I have no spark but upon performing the MSD checklist for checking if the modules are bad, the unit passes without faults. I have jumped the purple and green wires and have ample spark. I have spun the distributor with a drill and got 5. # volts AC at about 2000 rpms which is more than enough to trigger the MSD. I have since spun the distributor hooked to the MSD with ample spark. But when placed in the car and I try to crank it I am unsure if there is enough cranking force. I am using a starter from a Dodge Dakota 3.9. I am wondering if this could be a major factor in not triggering the distributor which has had 4 pickups in it (all new) and 2 new reluctor wheels. Will an aftermarket high torque starter work as the motor has high compression and spring pressure? Any help would be greatly appreciated. Thanks in advance.
Posted By: RapidRobert

Re: fresh motor no spark, help! - 08/18/15 05:44 AM

it sounds like the MSD and the dist have both past muster. what is left (assuming they are OK) is how you have it wired. Not sure how much cranking you wanna do with a new cam breakin looming before regooping the cam. Not sure if 13.5 is above what a reg starter can handle but I'd WAG no especially since the ign is down there is no compression building from the mixture being fired, just what you would get from a compression test
Posted By: ruderunner

Re: fresh motor no spark, help! - 08/18/15 08:59 AM

What you got for battery cables? Is battery fully charged? Sounds like you may not have enough electrical oomph to crank and spark.
Posted By: Dean_Kuzluzski

Re: fresh motor no spark, help! - 08/18/15 10:45 AM

Starting circuit is a separate circuit from the ignition circuit.
Did you remove the inner valvespring for cam break-in?

I'd hook up a battery charger while cranking the motor. Battery may be marginal as mentioned.

You should be able to hook up a sparkplug to the coil output wire (that would otherwise go to the center of the distributor/rotor), ground the electrode of the sparkplug, crank the starter, see every spark generated by the distributor as it spins. Verify that, plug things back together as intended, and if the distributor is in the motor right, it should fire up.
Posted By: SS/ Demon

Re: fresh motor no spark, help! - 08/18/15 12:17 PM

The motor was already fired up on the dyno broken in and made 8 pulls before going in the car. Also the Battery cables are double 00 gadge. I also am currently charging the Battery today. Plus the MSD is wire as follows, heavy red wire gose to the Battery kill in the trunk right off the Battery.the heavy black wire to chassie ground ,the little red wire is hooked up at switched 12v at the fuse box, the whte and grey are dead ends, the purple and green go to distributor, and orange and black to coil so it is a really simple set up.
Posted By: therocks

Re: fresh motor no spark, help! - 08/18/15 04:12 PM

Did you paint the motor?I had no spark when I put mine together.The dist wasnt getting a ground because of the paint.Rocky
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