hi i got a question do any of u guys know anything about a coil that shares 2 cylinders.. well i want to get to the bottom of this.. okay i heard when 1 fires, 4 fires too but its at the exhaust stroke if thats so.. than piston 1 would be at tdc gettin ready to ignite and booommm forces the piston down... if 4 is at exhaust then that means it didn't start it yet cuz exhast is when the piston is at the bottom and pushes it up and out thru the valves and nuymber 4 can;t ignite when piston is going up it will bend a rod..


so is it true 1 and 4 only fires during power stroke even if 1 coils shares 2 cylinders.. everybody is saying someything different..

 

nobody knows?

 

dude, wait, what?

 

so nobody gets it?

 

Only on DIS ignition can you do that. The purpose of that is to try and burn any left over hydrocarbons that may have been missed during the combustion stroke. This cant happen on a HEI ignition because the rotor sends the spark to only 1 plug at a time.

Also, when the piston is on the exhaust stroke, the exhaust valves are open, so if it does ignite any unburnt fuel, it wont try and force the piston back down, it will just go out the valve because of backpressure.

 

yes on some engines one coil is used for 2 cyls. This is typically callled lost spark or wasted spark ignition. It is somewhat simpler to implement in engine management but more importantly it is less expensive to manufacture.

 

yes but when 1 fires 4 must be at the top to fire so the combustion forces it down so 4 isn't at exhaust stroke. damn i'm lost.