72 Demon not starting

-

Airborne_Tanker

Well-Known Member
Joined
Mar 11, 2012
Messages
279
Reaction score
35
Location
Louisiana
Hello everyone so I’ve been working on my 72 trying to get it up and running. I installed a MSD 6AL and Coil on it and not getting anything. I have spark the Holley red fuel pump is regulated and holding 7psi, the carb is spring fuel. Only thing I can think of it timing. The engine wasn’t built by me so I’m sure if the cam specs but I pulled the timing cover off and looked at the timing marks and at TDC for number 1 both dots are at 12 o’clock. I rotated the engine over by hand watching the valves and verified it is definitely on the compression stroke there. Closed that back up installed the MSD distributor left the cap off to wiggle the rotor to make sure it triggers and it is. I know the common issue is the MSD not getting constant power so I wired mine to a toggle switch to make sure it stays at 12v. Rotor is pointing directly at my number one plug wire when it’s all hooked up and nothing. Not even trying to start. The engine ran great before I brought it in to do maintenance that hasn’t been done on the car in decades. I’m out of ideas at this point other than swapping in the 340 cam I have in a spare engine.
 
The new MSD have a really high fail rate so even if it is new dont think it is good.
 
The new MSD have a really high fail rate so even if it is new dont think it is good.
That sounds about right with quality control that’s been going on for a few years. I’m on the fence of yanking everything out that’s “new” and put the old stuff back in.
 
It’s passed all of their “tests” they say do and if it does what they say it’s supposed to it’s good.
 
If it ran before then its not your cam or timing chain. Have you pulled the distributor and turned the rotor 180 deg, set it back in and tried to start it? Did the Oil pump drive move up at all? That can throw off timing too if it comes up too far and moves a tooth or two.

How good is your engine ground? What do you have for grounds?
 
Pump shaft could have possibly moved engine is grounded with a strap to the chassis and engine to battery.
 
I installed a MSD 6AL and Coil on it and not getting anything. I have spark
FIRST:
On the factory Mopar the ignition system is split at the ignition switch, into TWO modes; crank and run. For an aftermarket ignition system, these usually have to be joined under the hood. AND, the tach has to run off it's own signal.
Check your MSD instructions as to how this is all done.

Ok then

>If you have spark at the right time, on every cylinder, DURING BOTH "CRANK",AND "RUN" MODEs
>the carb has fresh, uncontaminated, fuel in the bowls, AND
>your CCP is more than 60psi, AND
>The engine is both sucking and blowing,
>Then it has everything it needs to run............ except;
We don't know if the plugs are still working. and
Starting an engine on 60 psi is a lil tricky. Everything has to be working just right. It starts way easier at 160psi.

My guess is
(if the MSD is sparking during crank-mode),
1) that your plugs are gas-flooded, and/or
2) your rings are dry and/or
3) the throttles are not open far enough, and/or
4) the choke is not doing it's job properly.

My Opinions are
>you need to pull the plugs and look at them, and
>while they are out, put some oil back in the cylinders.
>IMO, and I have proved this, sorry Dano, the engine does not actually care where the oil-pump drive is, IF, you just reclock the wires in the cap, to the new #1TDC compression, rotor position.
> if the D is out 180*, and the engine is NOT flooded, it will backfire out the carb, when cranked.
>To aid in making CCP you can set the cranking timing anywhere in the window of 10 to 25 degrees.......... the more timing it has, the more throttle it's gonna need, to ensure the transfers will deliver after she sputters to life. somewhere around 16* will be fine.

To clear a fuel-flooded engine;
>one that has had the cam previously broken in, and
>this assumes, that the CCP is adequate.
> But, if the engine has very poor CCP, you're gonna need to re-oil the cylinders first.

Here's what I do;

1) I take a really long screwdriver, clean it, then stick it down into the carb, all the way to the bottom of the plenum. This ensures that BOTH the choke, and the throttles are in Clear-Flood mode. Then;
2) do not touch the gas-pedal, and start cranking
3) It's gonna start firing on maybe just one cylinder, do not release the key, unless it's shooting flames out the carb, just keep cranking. Soon another cylinder will clear and join in, just keep cranking. After three or four are popping out the exhaust, she'll probably start running. Just keep cranking until it starts reving up on it's own, then release it to "run" mode, and let it clear itself out. (no you can't hurt the starter, it has an overrunning clutch system in it, that prevents starter damage)
If the rings have oil, this cranking business may only take 15/20 seconds. But if the CCP is way down, it may take way longer.
4) once the rpm gets to be over about 2000rpm or so, let it continue running, but go take that screwdriver out.
5) as the rpm comes down; 1) don't let it stall, and 2) Crank up the curb idle to keep it over say 1200 for a while. then
6) without regard to the actual ignition timing numbers, just advance the timing until it revs up to the highest it gets to be, then crank the rpm back to 1000>1200, then readjust the timing by ear, to not labor the engine; don't worry, she'll tell you.. After she is warmed up and sounding pretty good, bring it down to say NOT LESS than 800.
7) now bring the no-VA, Idle-timing back to ~10>16, and reset the idle speed and mixture screws as may be required, (Towards 16* for a cammed engine, and towards 10 for a stocker.)
8) if an auto-trans, check the auto trans fluid level as per the rules. Then,
shut it off, and check all the other fluids. If the oil is thin and runny or smells like gas, change it. Top up as necessary, look for leaks.
9) ready for a test-drive; Well, except you gotta check and reset the Power-Timing as may be required. If that action kills your idle timing, then you got some modifying to do. If the Power-timing gets over 36* degrees stay out of the Secondaries.
If you experience detonation, on the test-drive, STOP! back out of the throttle, go home and fix the D.
10) But if the cam has not yet been broke in, then you better not use the above method. We need to light that thing off right.
 
Last edited:
plugs are definitely flooded just pulled them out going to grab some oil and an oil can to put some in the cylinders.
 
Back yard way. Do you have compression and rotor position all in one test.

Take number 1 plug out and take the distributor cap off and lay it to the side.

Hold something over the spark pug hole to cover it. Have someone turn it over while your holding some pressure on the spark plug hole . See where the rotor is facing every time you here the air from cylinder one. Where ever that rotor is facing that is Number one. Now you'll have an Idea of how far off your wires are.
 
Yea that’s the way I did it earlier this morning it’s as close as I can get it. It’s charging right now and I’m good to try to clear out the gas it’s probably flooded right now.
 
Shut off the fuel to the carb. Until after you here it at least try and fire up with whats in the carb. This way you are sure its not flooding itself.
 
I’m going to get back after it after the Army Navy game today. Worst case I’ll put my Mopar ignition back on it.
 
-
Back
Top