Interesting timing/pickup info for 85-89 V-max

[Birdoprey]

There are two VR sensors, each with TWO individual pickups. Each VR sensor is mounted 70deg from the other. There are two triggers mounted on the flywheel, each 180deg from one another and each is physically off-set from the other. One rides on the inside edge of the flywheel and the other rides on the outer edge.
The two pickups on each sensor are offset from each other,one in-line with the inner flywheel trigger, and the other in-line with the outer flywheel trigger.
The inside pickup on the front sensor fires cyl #1
The outside pickup on the front sensor fires cyl #3
The inside pickup on the rear sensor fires cyl #2
The outside pickup on the rear sensor fires cyl #4

So, heres how the Vmax fires:
*Cyl #1 fires, then the crank rotates 70deg
Cyl #2 fires, then the crank rotates 110deg
*Cyl #3 fires, then the crank rotates 70deg
Cyl #4 fires, then the crank rotates 110deg
Cyl #1 fires, then the crank rotates 70deg
*Cyl #2 fires, then the crank rotates 110deg
Cyl #3 fires, then the crank rotates 70deg
*Cyl #4 fires, then the crank rotates 110deg
*Cyl #1 fires(back at the start

The "*" indicate when that cyl is TDC on its compression stroke(power stroke).
So, this is a true wasted spark arrangement, firing each cyl every 360 deg. Just waaaay more complicated than what i'm used to seeing(or have ever seen for that matter!)
You can see that cyl #1 fires(power stroke), then the crank rotates 180deg, then cyl #3 fires(P/S), then the crank rotates 250deg, then cyl #2 fires(P/S), then the crank rotates 180deg, then cyl #4 fires(P/S) and finally rotates 110 deg to start over again with cyl #1(P/S), giving the V-max its 1-3-2-4 firing order. There is just ALOT more going on with the pickups/coils than one would think!
This info may or may not be of any interest, but it took me so long to get it figured out i just had to share...

 

[RazoR333]

Re: Interesting timing/pickup info for 85-91 V-max

Good info for my documents files ,..thx for sharing BP. :eusa_dance:

 

[johnpclynch]

Re: Interesting timing/pickup info for 85-91 V-max

Does that mean that if you rotated your front cams 180deg the engine would still run but with a different firing order? :ummm:

So, it would then fire:
*Cyl #1 fires, then the crank rotates 70deg
*Cyl #2 fires, then the crank rotates 110deg
*Cyl #3 fires, then the crank rotates 70deg
*Cyl #4 fires, then the crank rotates 110deg
Cyl #1 fires, then the crank rotates 70deg
Cyl #2 fires, then the crank rotates 110deg
Cyl #3 fires, then the crank rotates 70deg
Cyl #4 fires, then the crank rotates 110deg
*Cyl #1 fires(back at the start

(as above, the "*" indicates when that cyl is TDC)

There would be a "bigish bang" in the first 250 deg then nothing for 470deg! It might beat your gearbox up but I bet it would sound cool :biglaugh:


I remember messing up the cams on my Magna 700 when rebuilding it so instead of firing 1-3-4-2 it fired 1-2-3-4, it lost power & mpg went up!
It didn't take long to fix it though

 

[one2dmax]

Re: Interesting timing/pickup info for 85-91 V-max

Great work, However, please edit your years to reflect the correct configurations. 85-89 were the only years for the dual pickups (at least for the Vmax engines). 90 and up were single pickups (and diff flywheels).

Sean

 

[Birdoprey]

Re: Interesting timing/pickup info for 85-91 V-max

Great work, However, please edit your years to reflect the correct configurations. 85-89 were the only years for the dual pickups (at least for the Vmax engines). 90 and up were single pickups (and diff flywheels).

Sean

I can't edit that part(title). Maybe Buster or? Sorry, about that.

 

[maleko89]

Fixed!