I have a 96 lt4, the common problem of the water pump going bad happened to me, the optispark was saved. I got a bad pump and this one ruined the optispark. I have it all apart except the last bolt holding it on. In the manual it says to remove the crank pulley, that seems impossible. Before I do anything drastic and try to lift the engine up enough to pull it off, I was wondering what the trick, if any, is to remove the optispark, or an easy way to get the pulley off. Also i had a problem with getting coolant in the car last time. I used a air pump to do it last time. Then people told me to jack the front of the car up but by that time it was already miss firing.
Thanks for the help:
Shane

 

Good info here.

Now for the not so easy task of removing the damper. You need to remove the damper to gain access to the opti-spark. There are 3 bolts that hold the damper onto the hub. I marked the damper so I could reinstall it in the same position on the hub, and it only goes on one way. After removing the 3 bolts, you'll probably have to get under the front end and using a soft drift pin or a wooden dowel (1 1/2" dia by 12" or so) and a hammer, loosen it from the hub. Don't just hit one part of the damper; try to hit it all around so it doesn't bind. This is a PITA. Once it comes free it is time for your first beer; you've earned it. Voila, the dreaded opti-spark is now in view. Mark each spark plug wire so you know where they go when it's time to reconnect. The opti-spark has the terminals marked and I made it easier to see by using a Sharpie marker. Pull the plug wires out of the opti-spark. Remove the coil wire as well. Now would be a good time to replace the plug wires if you want to. Remove the 3 bolts that hold the opti to the timing cover and soak them, too. Unplug the connector going to the opti (11 o'clock position as you look at the engine hope you don't have a digital watch). Carefully pull the opti off the timing cover and from this point on DON"T TURN THE ENGINE OVER, until we put the opti back on. If you are not replacing the opti, doesn’t turn the little gear that came out of the timing cover, this will make it easier to reinstall later.

Time for one of the hardest part of the project IMHO. Hub removal. This is not like any other hub removal I've done. GM has a special tool kit just for the LT-1/4 it is "J-39046" it is worth its weight in gold. Time for a beer and enough for today. The next morning, I tackled the hub pulling. Using the Kent-Moore LT-1's instructions made it easier than expected. I did disconnect the hydraulic line going to the rack for better clearance. No, I did not have to raise the engine. Oh, before you pull the hub, make a mark on the timing cover and hub that matches so you can reinstall the hub in the same position. The Helm's manual makes a big point to make sure the damper is positioned back on the crank in the same position. Some say it doesn't matter, but I went with the manual and marked it. If your hub and damper were like mine they were pretty rusty, so I cleaned mine up and painted very lightly. If you are going to take the timing cover off, you have to remove the oil pan.

 

But wait there's more!

How do you raise the engine? On my LT-1 (92) there are two nuts that hold the motor mounts to the 45-degree cross members. Remove those nuts. The stud is just about 1" in length so you can judge by that how high to jack. Where to jack from? I have a 6 speed and I used a block of wood on my axle jack and raised the drive train from the bell housing. Remember, just 3/4" is all you'll need

 

But you shouldn't need to raise the engine or remove the hub just to change the Opti. You only need to do that if you are removing the timing cover/changing the camshaft. The Opti can easily be taken out once you remove the balancer from the hub.

Steps to remove the opti.
1) Raise front end of car. Doesnt need to be a ton, I've done it with Rino-Ramps out on the street in front of my apartment.
2) Remove air filter housing, and ducting.
3) Remove coolant hoses going to and from radiator.
4) Take of serp belt.
5) Remove alternator (you might be able to do it without removing the alt, but it makes getting at the water pump screws much easier, and the alt only takes 2 minutes to remove).
6) remove water pump. As mentioned in the other Opti thread, one of the bolts takes a long socket, and a universal joint to get to. Be patient.
7) Now you can see the opti, but the balancer is in the way. Un-do the three bolts holding the balancer to the hub.
8) Make sure the balancer is marked. There should be an arrow on once side of the hub that lines up with a mark on the balancer. If not, you can do this yourself. I found cleaning the balancer and hub wth some simple green, then using white-out works. I also put a black sharpie mark next to the whiteout in case the whiteout comes off (why not just use the black sharpie?? Its much harder to see when re-installing..)
9) Get under the car, and with a long block of wood, and a hammer, GENTLY tap the balancer off. Make sure you keep rotating the balancer so you are going at it from all sides. This takes time and patience, but soon it will be loose, and will come off.
10) Mark then pull the plug wires.
11) The opti at last. Undo all bolts, and pull her off.

Note: When re-installing the opti. MAKE SURE IT IS ALL THE WAY ON!!! It will snap in place, but not easily. I thought I was going to break a blood vessel in my forehead I was pushing the damn thing on so hard, then finally, CLICK! If you do not do this, your opti will go bad within a couple of thousand miles!!! I think this is one of the biggest mistakes people make when changing an Opti.. you need to make sure it is all the way on.

P.S. it has been a couple years since I changed an Opti. There may be a bracket, or something in the way that you need to remove that I am forgetting.

Also, I recommend taking digital pictures while you disassemble it. It is amazing how easy it is to forget.. "How did that bracket go again?!?!"

 

As others have said, drive the pulley off from below. I used a long pry bar (jumbo Snap-On Screwdriver, actually), and a hard rubber mallet. Remove the three bolts, and crawl under the car. Place the tip of the driver as close to the hub as possible, but so that it's resting against the rear of the pulley (not the hub). Give the driver a few whacks with a mallet, and it'll probably pop off of there. You may or may not need to rotate the crank and whack it from other positions (I didn't need to).

After you get the pulley off, rotate the crank so that one of the three wings on the damper hub is at the 6 o-clock position. This will orient the other two wings at approximately 10 and 2 o-clock. The Opti will then clear the hub on its way out.

Clean the damper and hub mating surfaces of all grit/rust/grime, and apply a very thin coat of anti-sieze compound before you reinstall the damper. Doing so will nearly assure you that it'll come off easily the next time.

As others have said, make sure your Opti is fully seated against the timing cover, but do NOT use the mounting bolts to draw it up snug. Bump it with the heel of your hand, as required, but do NOT force it on there.

Follow the cooling system refill procedure in the Factory Service Manual, and it should go just fine. Make sure to bleed the air out using BOTH of the bleed screws (should be one on the throttle body, and one on the thermostat housing).

Unless they are nearly new, I'd also recommend you swap the plug wires, all coolant hoses, and the serp belt while you're in there.

Good luck with it.

Be well,

SJW

 

They pretty much summed it up. The damper is easy to remove (as stated above). The hub, which you do not need to remove, is a PITA.

 

I did opti (twice) and never pulled the pulley off the hub, nor the hub off the crank. Used a snap on 'crows foot' puller and just slid the hub/pulley together until the pulley was against the p/s rack. It gave me just enough clearance to change the opti.

 

This is really good information to know.

 

This is seriously the most difficult way to remove the opti I can think of. The hub is one of the more difficult things to move on this car- why on earth would you even bother hassling with it if you could avoid it?

Remove three bolts holding hub to damper. Using a long rod (I used a jack handle), place the end on the INSIDE of the damper and give it a few whacks with a hammer. Viola! It's loose and you can now remove it AND the opti without ever hassling with the hub.

 

hey thanks alot guys. hopefully i'll have the time off work to get it done by the weekend. its starting to get warm out and im getting axious to take it out for a ride. but whats the trick to getting the antifreeze back in, or the easiest way. your info was a really really big help, i was a little worried there for a second.

 

Because my pulley did not want to come loose from the hub. Took off the 3 bolts, and center bolt, the puller bolt fits right thru the ps line loop. It seemed easier just to pull the whole thing forward than to jack up the engine so I could get bar in there to knock the pulley loose. Another way to achieve the same end.

 

You have to use the bleeder screw to get the air out when refilling with coolant. Otherwise the air will be trapped in the enigine and it will overheat quickly. You will see the bleeder from passenger side by the throttle body. Brass fitting with slot for a screwdriver. Just loosen it few turns to bleed out the air (engine running) as you fill the radiator tank (not the overflow, the 'main' tank).

 

So whats the final decision? hub does or doesn't have to come off? conflicting info here.......GGGGGGG

 

Hub does NOT have to come off.

3 methods:

1) Just take the balancer off (IMHO this is the easiest if you dont have a super-stuck balancer)
2) Use a crows foot to move the hub and balancer forward together until the Opti clears (IMHO, much more difficult than option #1, unless your balancer is seized to the hub)
3) Remove the balancer, then remove the hub. I suppose you could do this if you really are a masochist, as there is no reason to remove the hub.. all you need to get out of the way is the balancer.

 

The hub does not come off with either approach. Sorry to confuse you.
Easiest way is as others said, pull off the belt and belt tensioner, remove the 3 bolts inside the crank pulley and take off just the pulley.
I am confusing you as my pulley seemed frozen to the hub, so I just used a puller and slid the pulley and hub forward as far as they would go without removing either one. Two ways to go about it, same result.