72Challenger 440-4 speed

[Paul72chal]

Hi everybody, been a member for e few years now but haven’t spent a lot of time here. I’ve been restoring a former 318 automatic 72 Challenger and recently got the newly re-built 440/833 put in. I’m trying to get it fired up, but are just getting backfires so far. I’ve squirted gas into the carb, maybe I need to try starting spray. Haven’t cranked a new motor in 40+ years. Any ideas?

Thanks

 

[Carolinachallen]

Maybe double check the firing order, and possibly move the distributor a little bit one way or the other. I assume you can see a stream of gasoline in the carb when you open the throttle.

 

[moparleo]

If everything is adjusted properly the engine should start immediately. If it doesn't DON'T keep cranking it. You are only going to cause damage to the bearings etc...
Compression, fuel, timing/ignition.

Verify TDC.
Verify distributor is indexed properly, proper firing order,
Verify ignition has spark with switch turned to on position,
Verify proper spark plug type/gap,
Fuel in float bowls ( use a squirt bottle and small hose to fill thru the vents)
Verify accelerator pump functions,
Battery fully charged ( 12.5 V or higher)
Do this outside, not in garage etc.. Fumes, fire possibility.
Have fire extinguisher, bucket of water with a towel soaked etc.. just in case.
Have a friend with you to get an extra set of eyes for leaks etc...

 

[Paul72chal]

Thanks to all for the responses. I’ve read in another thread about it being “180 degrees out”. What does that mean, and how do you fix it? This is it, short the cap.

 

[HooToTheCore]

180 out means that your #1 cylinder is on the exhaust stroke instead of the compression stroke when the distributor is set to fire on #1.

Remember crankshaft goes around twice for each rotation of the camshaft.

 

[chilsam]

Thanks to all for the responses. I’ve read in another thread about it being “180 degrees out”. What does that mean, and how do you fix it? This is it, short the cap.

sounds 180 out...try puting # 1 dist wire on opposite side of dist directly across from fact #1 then run the firing order n order from there in dist rotation...if its 180 out it will fire up....THEN pull dist after putting the #1 piston on compression stroke "FIRING" and put it back in correct position...or you could just leave it and drive it ???..You'll have to verify firing stroke by taking cover off n watchn intake valve open then close...forgot that if u pull the dizzy in fix rotor position n replace

 

[70chall440]

Ok, so do this

rotate the engine by hand or bumping it with the starter until the timing mark on the dampener is aligned with the timing mark

pop the distributor cap off and see where the rotor is pointing, if it is not pointing at/near the #1 spark plug terminal then you need to move the distributor (loosen the retaining bolt and rotate it) UNLESS it is pointing at the opposite side as the number 1 terminal. If this is the case the distributor is 180 degrees out.

If that is the case, then you need to remove the distributor, rotate it 180 degrees and put it back in and put the distributor so that it is pointing at the #1 terminal.

Then verify the firing order making sure that you are going in the right direction (big block rotates counter clockwise).

At this point the engine should fire, may not run but shouldn't spit through the carb repeatedly. At this point it will be a matter of ensuring the carb is working, the plugs are functioning correctly, etc. and it should start and run.

 

[HooToTheCore]

You can't simply rotate the crankshaft to TDC and assume that #1 is on the compression stroke. It could be on the exhaust stroke. That is how you can get it 180 out. You must observe the valve positions (both closed) at TDC, then you can determine which wire on the distributor cap is #1 (where the rotor is now pointing).

 

[Paul72chal]

So sure enough, I 180’d the distributor and it fired up instantly. I’ve got a pretty aggressive cam, it timed out around 12 BTDC.

Thanks again for the support, this is an awesome group.