LT1 Opti spark question

[e vassar]

Originally Posted by KRatcliff

I use the MSD 83811 replacement for the GM Optispark. There is a metal wheel inside that has 360 small slots around the outside and 4 wider slots on the inside. You can use metal tape to block off all the holes except for the one that is to trigger as a cam sensor. The one hole that will be open is one of the 4 on the inside. I have to look at mine because I had a blank laser cut without any holes, but that one.

The harness is already there and it will plug into a Fast XFI system and I am sure the BigStuff would be the same. The purpose of the cam sensor for sequential is to see where the number 1 cylinder is in the firing order/stroke each time you shut off the engine. Otherwise, sequential tuning wouldn't work correctly.

On the subject of sequential tuning. How do you plan on measuring each cylinder for their respective O2 readings in order to make adjustments?

We unplugged the opti spark and are just using the crank trigger. The opti is just a cap and rotor function now.

[KRatcliff]

Originally Posted by e vassar

We unplugged the opti spark and are just using the crank trigger. The opti is just a cap and rotor function now.

Yes, it will be batch fire only which isn't bad. It will still run pretty well.

[Jeff Niceswanger]

Originally Posted by KRatcliff

Yes, it will be batch fire only which isn't bad. It will still run pretty well.

Tuners, and racers have debated the Batch fire verse Sequential fire for years. IMO, for all the expense and sometimes hassle to get the cam sync operational is just not worth it. Run batch fire and be done with it. Cam Sync's are mandatory for Coil on Plug applications, but if your car has a distributor/rotor w/MSD box I'd save your dough. For one thing, it's something else to mess up and cost you a round. Another thing is, for the novice, an ill operating cam sync system can be a bitch to diagnose.

[KRatcliff]

Originally Posted by Jeff Niceswanger

Tuners, and racers have debated the Batch Fire verse Sequential fire for years. IMO, for all the expense and sometimes hassle to get the cam sync operational it's just not worth it. Just run batch fire and be done with it. Cam Sync's are mandatory for Coil on Plug applications, but if your car has a distributor/rotor w/MSD box I'd save your dough. For one thing, it's just something else to mess up and cost you a round. Another thing is, for the novice, an ill operating cam sync system can be a bitch to diagnose.

You are right about it being a bit difficult and complex. We went through it and took all the steps we felt necessary to tune it properly. It definitely made a difference on our cars and we wouldn't go back to batch fire.

Of course, we also run Open Loop/Alpha A. That is another point of contention for some.

[Dan Fahey]

Originally Posted by e vassar

I have read that some LT1 racers are disabling the processor in the opti spark distributor so it basically is only a cap and rotor distributing spark to the plug wires. I believe this is called "batch fire" we have a crank trigger a BS3 and 7AL3 . So do I need the processor in the opti spark? How will the BS3 pulse the injectors without the signal from the opti spark?
Thanks

I have rebuilt several Opti's.
Stopped buying new ones if the Led Trigger is good.
Also a working Opti has the Rotor Clocked Correctly.

For Drag Racing, Remove everything.
If you have a good Trigger unscew it and save it.
Tape or Plug the Opening.

Save the Trigger Wheel if not bent.

Install the Rotor and Locktite the Screws.

Take the Long Electrical Connector that goes into left side of the Opti.
Cut the Wires and Install the Connector.
Plugs that hole.
Prevents water or moisture from gettng inside the Cap and Rotor.

There are two small tubes on the bottom.
Put a Rubber hose on Both.
Let them hang.