Alternative firing order on 5.9 magnum?

[Crawford]

as I was replacing my spark plug wires I noticed today before i changed any that the firing order was different from factory, not sure why. But I changed it back to the factory 1-8-4-3-6-5-7-2 firing order. The firing order on my truck was set 1-6-2 ---- for some reason, can't remember the others.

Has anyone heard of swapping the firing order on a magnum?

[m37dsl]

This might get ugly...

[rocklobster87]

um. . does it still run?

[Crawford]

Originally Posted by m37dsl

This might get ugly...

Probably.


Rocklobster - I haven't thrown the intake manifold back on the truck yet to find out.

when it was 1-6-2 etc. it had a fairly smooth 850-900 rpm idle. even w/ a blown out plenum gaket.

[Elwenil]

The only real reason to change the firing order is if the distributor driveshaft was put in wrong and even then that doesn't change the order, it just moves it around the cap a little bit. To my knowledge there is not an actual "alternative" firing order for a Mopar small block.

[Crawford]

Originally Posted by Elwenil

The only real reason to change the firing order is if the distributor driveshaft was put in wrong and even then that doesn't change the order, it just moves it around the cap a little bit. To my knowledge there is not an actual "alternative" firing order for a Mopar small block.

i didn't think so either. we'll start her up n see how it runs.

[crashnzuk]

You know #1 is the drivers side front cyl right? Drivers bank is 1-3-5-7 and pass bank is 2-4-6-8. Just thought I'd share in case you are a Ford man
Travis..

[NMike]

some special cams have the firing order changed, but i have only heard of that on chev motors.

i suspect you checked it wrong or someone put it together wrong.

[Crawford]

Originally Posted by NMike

some special cams have the firing order changed, but i have only heard of that on chev motors.

i suspect you checked it wrong or someone put it together wrong.

I had a friend sitting there with me, let him check it too, he also noted it was 1-6-2.

at this point, I'm kinda surprised it ran so smoothly, You could not notice it running any different from my friends 01 5.9L

[clinta]

if it ran so smothly why is it tore down?? I say quit wasting time on here get out there and put it back together and then YOU will have something that you can try to diagnos. other wise this is all speculation and you are wasting your time along with everyone else that throws some cockamame idea your direction.

BTW the cams that they are speaking of are normally run in a circle track engine that swap 4 with 7 and then the order is 18736542

[Crawford]

Originally Posted by clinta

if it ran so smothly why is it tore down?? I say quit wasting time on here get out there and put it back together and then YOU will have something that you can try to diagnos. other wise this is all speculation and you are wasting your time along with everyone else that throws some cockamame idea your direction.

BTW the cams that they are speaking of are normally run in a circle track engine that swap 4 with 7 and then the order is 18736542

installing plenum kit from hughes so it stops burning all my oil..

everything should be back on tomorrow. once I get the throttle body back i'll fire it up.

[Crawford]

started the truck up real quick tonight, ran perfect. oddly enough it doesn't lope anymore..... still sounds like theres a sucking noise once i kill the engine for a very brief moment but it's loud enough with the filter off.

[rocklobster87]

Originally Posted by Crawford

The firing order on my truck was set 1-6-2 ---- for some reason, can't remember the others.

cylinders 1 and 6 are companion cylinders, there is absolutely no way these cylinders could be consecutive in the firing order of a running engine. say your #1 cyl. fires at 8deg BTDC on its compression (idle), your #6 cyl will then fire 90 crank degrees later, just under 1/2 of the way through its intake stroke. At higher rpm, the #6 cylinder will fire around 1/3 of the way through its intake stroke. Regardless of what the rest of your alleged firing order was, if by some miracle this motor did run, it would have made no power, and your #6 intake valve would have been cooked like a christmas goose. Not to mention the catastrophic backfiring you would have experienced through your intake manifold.

Im glad to hear that it runs, but there just had to have been something wrong with your initial observations.

[Crawford]

Originally Posted by rocklobster87

cylinders 1 and 6 are companion cylinders, there is absolutely no way these cylinders could be consecutive in the firing order of a running engine. say your #1 cyl. fires at 8deg BTDC on its compression (idle), your #6 cyl will then fire 90 crank degrees later, just under 1/2 of the way through its intake stroke. At higher rpm, the #6 cylinder will fire around 1/3 of the way through its intake stroke. Regardless of what the rest of your alleged firing order was, if by some miracle this motor did run, it would have made no power, and your #6 intake valve would have been cooked like a christmas goose. Not to mention the catastrophic backfiring you would have experienced through your intake manifold.

Im glad to hear that it runs, but there just had to have been something wrong with your initial observations.

It's the only explanation. Thanks rock, that helped a lot.

[Crawford]

what I don't get, is when i have it in gear at stop light, it seems like the motor is bumping/vibrating like it is making a large ammount of power, it shakes the whole truck when i put it in park the bump or the vibration calms down a bit. could i be feeling a missfire? once i get on the gas every things good & smooth, it idles like normal though audibly.

[rocklobster87]

what are you idling at?

[Crawford]

Originally Posted by rocklobster87

what are you idling at?

in gear around 600ish