What is the firing ordering of a 20 liter duel head cam?

Answer 1

Without a lot more info on what motor you have it is impossible to tell you what your firing order is, and i would only Google it anyway (which i guess you can do yourself)

So instead i have given you a way to work it out for any motor.

I'm not sure if you meant to say 20Lt or 2.0Lt so i am going to answer the question as it was written, however the method is the same for a 2.0lt as a 20lt.

First take a piece of paper and down the left side write the number of cylinders you have, ie. write the numbers 1 to 12 if its a V12 or 1 to 10 if its a V10 ect.

Second go remove the rocker covers off the motor so that you can see the top of the valve stems (don't disassemble the valve train though)

Now hand crank the motor so that piston 1 has its intake valve just beginning to open.

On your piece of paper you can now write a 1 next to the 1 already on your piece of paper.

Now continue to hand crank the motor and watch carefully for the next intake valve to open. work out which piston it is and write its number next to the number 2 on your piece of paper.

Continue in this fashion and eventually when you fill up the second column on you piece of paper you will have your firing order read from top down in that column.

Now lastly before you do anything else, go down and by the service manual for you motor / car and do a lot of reading before you go pulling stuff apart again.

Your question demonstrates that you do not yet have the requisite knowledge to do more than top up your water and oil, but thankfully that's easy to fix.

Regards,

Nico