vstol

can the opti spark be installed incorrectly?

Rick92

The shaft between the opti and block on my 92 was indexed and would only slide in one way(at least without forcing it) I guess it is possible but it is harder to install. Later Lt1's are changed but I believe they are still indexed I am sure someone will chime in. :cheers:

vstol

Thanks I have not pulled the CAM yet for the change but looking at the 96 opti spark there are 3 pedals on the back of the Opti spark and in one of them has a slot which I assume is where the dowel pin from the CAM goes. I have not tried it yet but I believe I am right? Thoughts

John Row

The 95-96 can be forced into the wrong position. If it slips right on, then it is in the correct position.

vstol

Thanks, I had read that some where before

PurpleC4

Attached is a copy of a procedure that I wrote a long time ago, and has been improved over a period of time with feedback from other Forum members.
It has been posted many times.

LT1_LT4 Balancer/Hub Removal
By following this procedure you will gain access and be able to change the three front timing cover seals (Water Pump, OptiSpark Drive, Front Crankshaft/Balancer)

Unlike its SBC predecessor, the LT1/LT4 Balancer is a two-piece assembly consisting of an (inner) hub, and (outer) balancer/pulley. Removal of the assembly can be frustrating if approached in the conventional way. By following the procedures below, you can safely and quickly remove the assembly with little or no problem.

You may want to consider using Rhino Ramps or jack stands to gain additional access space and elbow room underneath the front of the engine.

1. Drain the radiator by opening the drain valve on the lower right hand (passenger side)
2. Remove the serpentine belt
3. Remove the upper radiator hose
4. Remove the water pump. When removing the water pump, it is important to remember that the LT1/LT4 water pump is attached to the engine with 3 bolts on each side, vs. its predecessor, which only had 2 bolts on each side. The center bolt on the driver side is a challenge, but can be removed without removal of the power steering pump. When removing the water pump, take care to remove the pump drive coupler along with the pump and place it on the pump drive shaft for use when re-installing the pump.
5. Mark the coil wire and all plug wires at the OptiSpark cap for easy reference when re-installing the OptiSpark unit after balancer seal repairs have been completed.
6. NOTE: There is no need to separate the balancer pulley from the hub if you intend to pull the hub off anyway. The only time you need to separate the pulley from the hub is if you are simply changing the OptiSpark. There is a match mark that is cast into the balancer assembly that allows you to mate the two pieces together in the exact orientation that they come apart. If you intend to separate the balancer pulley from the hub, locate the marks and make note for re-assembly.
7. The balancer pulley is attached to the hub with three bolts. The bolts are 7/16” SAE standard, 14 threads per inch, ¾” length (not metric). Fully remove all three bolts, and if you intend to remove the unit as a complete assembly, jump to steps 9 thru 18. If you intend to separate the assembly, continue by rethreading one bolt by a couple of turns. It is now time to separate the pulley from the hub. Most pulleys have been found to be rusted in place and require considerable effort to separate from the hub. Spraying the inside of the pulley with penetrating oil helps. Do not strike the pulley with a hammer in your frustrated attempts to remove. The best method is to position yourself under the engine with a steel rod (or better yet a brass drift) and one healthy hammer. Position the rod/drift on the inside portion of the balancer when striking it with the hammer. This step requires more than a gentle tap. Try to position yourself so you can give a good solid hit at each rotation. Rotate the crankshaft 120 degrees after every couple of heavy hammer blows. Do not hit on the outer diameter of the pulley as damage can and will occur.
8. After successfully separating the pulley from the hub, it is now time to unbolt and remove the OptiSpark module. As with the water pump, a coupler drives the OptiSpark module and care should be taken to remove the drive shaft and place with the OptiSpark module for use when re-installing the unit. When the time comes to re-install the OptiSpark unit on the engine, you should pay close attention to the Notice below

Notice
Contrary to what all the books say, in some cases, the OptiSpark drive coupler can/will go on in more than one position. When the coupler is correctly installed, the OptiSpark unit will slide in place and rest firmly against the timing cover without forcing it into position. The drive spline in the rear of the OptiSpark is keyed. Pay close attention to the key, and match it up with the corresponding slot on the drive coupler.

9. Finally, it is now time to remove the hub. The center bolt that holds the hub on the crankshaft snout is 7/16” fine thread (not metric). I have found that I can generally break the center bolt loose by placing a 6 sided socket on the bolt, with a ½” breaker bar attached. By striking the breaker bar with that healthy hammer you just used in step #7, you can break the torque on the bolt.
10. Fully remove the bolt, remove the washer from the bolt, then re-install the bolt by 3 full turns.
11. Re-read step #10. If you skip this step, you are a screwed pooch.
12. The “General” was thinking when he installed the power steering rack hydraulic lines as he has installed a loop in the lines that allow the use of a balancer puller without interference of the puller jack screw. Check it out, you will be glad that he did this.
13. Use a standard balancer puller that requires the use of 3 puller bolts that fit into 3 slots on the crab portion. Make sure that you use a tip on the jack screw end that is a flat rotating plate, not a sharp point, because you will eventually place the jack screw end directly on the head of the center bolt of the hub and you don’t want to damage it.
14. Next, select three new (or used) 7/16” bolts that are of sufficient length to slip thru the puller and fully thread into the hub where you previously removed the 3 bolts in step #7. If you do not have 3 – 7/16” bolts that are the proper length, you can use bolts that are slightly smaller than the tapped holes so you can slip them completely thru the hub. Make sure that the bolts are of sufficient length so that you can insert them completely thru the puller assembly and the hub, with a flat washer on each end, and a nut on the backside.
15. Rotate the entire hub assembly until the (^) mark is at the 12:00 position before removing the hub. When re-installing the hub, make sure that you install it back in the same orientation. This is a balance mark, and although it really won’t make too much difference if you fail to do this, it is there for a purpose, so try to do the right thing here.
16. Position the puller onto the front of the hub, with the jack end of the jackscrew slid thru the power steering line loop, and attach as mentioned above.
17. You are now ready to slowly remove the hub from the crankshaft snout. The crank may start to turn as you apply force. Placing a 2x4 against the puller and left wheel "A" frame will stop the rotation. If you have access to a micrometer (click style) torque wrench you will find that it will take about 70 - 85 foot pounds of torque before you will see the hub start to move. As you continue to turn the jackscrew in a clockwise rotation, the hub will slide off the crankshaft. Keep doing this until you feel the hub come loose, or until you back it out against the shoulder of the center bolt. It may be beneficial to purchase a 3" x 7/16 grade 8 fine thread bolt and continued the removal with that. Without the 3" bolt you might not be able to get the hub all the way off.
Plan to use the 3” x 7/16” bolt when re-installing the hub back on the crankshaft after your repairs are complete. Just slide the washer over the bolt, start the bolt in the crankshaft, and mechanically pull the balancer back onto the crankshaft snout.

18. You have successfully removed the balancer hub. Now, time to R&R that front seal assembly.

NOTE: I am looking for feedback from those who use this procedure in improving the steps above, and adding a section for re-installing the balancer hub. Please e-mail me at PurpleC4@qwest.net with your feedback.
Purp

RichS

Yes you can force it on the wrong index. I did it :rolleyes: on my 95. Don't force it, let it easily slide in place.

Dan Parker '96

At least on my '96, when you look at the back of the Opti (where the cam pin would line up) there are three slots. Two of the slots are not perfectly rectangular. They have interference points.

If you line up the obviously correct slot with the cam dowel then it'd be tough to install the Opti incorrectly.

Rick93Z07

The beating, tapping, pulling, yanking, twisting, prying methods for dampener pulley removal that often result in damage are all obsolete. Loosen all three bolts about 1 turn. Start the motor and goose the throttle once and shut down within a couple seconds. Repeat this a couple times and then proceed with teardown. When you remove the three bolts the pulley should literally fall off in your hand. Let the engine do the work.

PurpleC4

I will have to give that a try next time Rick. It makes sense.
~ Purp :thumbs: