I offered to help a friend replace his water pump, optispark, wires, etc. I'm not familiar with the optispark distributors. Would folks recommend replacing the whole distributor or just a distributor cap kit? The car has a little over 100K miles.

 

brand new gm unit in my opinion. best way to go. id never do just cap and rotor, while you are in there just replace the opti with the water pump and let her fly for another 100k

 

 

Replace the opti! It may not be going bad, it may be going bad, it may not be going bad.
Since you will have everything else off, replace it! 100k is a good distance for an opti.

 

Do you guys still advise sealing the cap on with silicone?

 

 

Thanks for the advice. He'll be ordering a GM complete distributor.

 

What year is your friends vette ? The Gen I Opti, which are on '92 to '94 cars, are not as robust as the Gen II vented Opti found on the '95 and '96. Since you are not familiar with the Opti and it's location, use advanced search function to get hints and tips on R&R process.

In a nutshell, here is a list of what needs to be removed :
1) intake bellows and all connectors
2) Serpentine belt (be carful not to break the temp sensor mounted on WP. I use an offset wrench)
3) Water Pump (There are 6 bolts total on the LT1)
4) Belt tensioner (easy, 1 bolt, and needs to be removed for plug wire change)
5) Harmonic pully/balancer (needs removal to get Opti off)
6) Optispark

Notes:
-WP may be stuborn to come off from years of congealing. Gently pry it loose using pry bar. Remember 6 bolts to remove. Make note of which bolts leak coolant when you remove. These bolts need to be permatex'ed during re-assmble. Carefully wiggle the WP up and out from front of engine. It is tight and you may think you cant get it out, but you can.
- Your harmonic balancer may be rusted on. Spary with PB blaster the day before you do the job. Best way to coax it off is to jack up the car and get a 3 foot piece of 1/2" by 1" wood, a 2-3 pound sledge, and whack it from underneath, laying on the ground just about where the passenger front wheel is. The end of the wood needs to be placed on the INSIDE of the harmonic balncer. The balancer/pully is a 2 piece design, and if you bang it on the outside, you will distort the hard rubber compound that holds the 2 pieces together. Also, the balancer/pully is NOT keyed so make note of the position so you can re-install correctly. There is a triangular embossed mark on the inside of the balance that you can use as reference for position. When you re-install, coat the contact area of hub with anti-sieze to prevent any furure problems. This also helps to get the balancer to slip right back on.....

blah blah blah......sorry for the rambling. I have done WP's and Opti replacements on 3 LT1's and 1 LT4 so far. Piece of cake....after the first time !!!

Here's a pic of a freshly mounted Opti' on my '94. Note the TDC triangular shape on the Hub. You will line up the other triangular mark on the pully/balancer to this mark:

 

Also, I don't think you can find better service or a better price for any corvette prices than the "thepartsladi". I have no affilliation with these guys, but I have never, ever had a problem wih them. All thier stuff is the real deal, AC-Delco, and they ship FAST !!! They are great to talk to as well......Many others on this forum will tell you the same thing..

http://search.stores.ebay.com/Thepar...346802QQsofpZ0

 

Can you buy from them without going through ebay?

 

Yes, you can call them and order directly over the phone. That's how I do it now. Go to that link I gave and look for the 1-800 number at their site:

"If you have any Question's Please Call 334-493-1240 or 1-800-579-7046 DAVID OR STEPHEN "

 

Thanks. That page is like a candy store to a kid. I can see where some money is going to end up soon.

 

Thanks for the hints! My friends' vette is a 95.

These instructions are better than the shop manual. There's quite a difference from my 85 L98. I know everyone seems to drool over the LT-1 but I kind of like having the distributor where it's supposed to be and not behind a water hazard.

 

I think the plug wires are the hardest part of this job. Even with the front of the engine clear it is a PITA to get the driver's side routed through the little hole they fit in.

I would suggest clearly numbering the cap terminals and both ends of the wires if they are not already marked. When you are ready to put the distributor back in get the driver's side wires in place first, attach them to the cap, and then install the opti. Once you have that bolted in you can finish the installation of the wires into the looms and do the other side last.

The wires I used came from NAPA and they fit pretty well. However, they weren't numbered and didn't come with any of the protective looms that the originals had around them. I transferred the old looms on to the new wires but it would have been nicer to have new ones. I don' know if the GM wires come with looms.

 

You can order the O.E.M. looms and wire holders from Mid-America Motorworks (MAM), Eckler's Corvette Parts and other specialty parts catalogs.

Remove the fender panels to make accessing the plug wires easier. With all those components and accessories out of the way, it'll make for easier access.

Be sure you mark the wire's firing order so you don't cross wire anything and screw up the plug's firing order. And don't forget the anti-seize compound on the new plugs for those aluminum heads. Be sure and torque them in to specs.

The coil and other ignition wires in close proximity to the manifolds are protected from heat and insulation degradation by black sections of corrugated flexible tubing. You can purchase it at any auto parts store.

 

Nice photo. If you have any more, please post.

I just purchased a '94 with 61,000 miles and am expecting delivery this weekend. I am collecting as much info as possible and filing for future reference.

The optispark distributor is a new concept to me and I am still trying to understand how you account for engine timing after you install a new distibutor.

In everything I read I see no capability of rotating the distributor or using timing light . I did note that you mention a triangular boss and alignment but NO keyed insert for the pulley/balancer. Seems like this would be critical during assembly and if not aligned 100% accurately, it could cause a lot of problems?

I just received the Service Manuals (bought on ebay for $40.) and will look in there for explanations also.

Will the Gen 2 fit on a 94 or will I have too stay with original design?

K.C.

 

With the exception of the MSD, there is no timing adjustment on the optispark. They bolt in place and that is it. The MSD offers adjustable timing by means of a screw that gets turned. You would have to rig something up to see where you are setting it.

There are two ways to use a Gen 2 or vented setup, one is to go with an MSD or Dynaspark, they have provisions to connect inlet and outlet vents. The other way is go with an OEM unit, but it means changing out the timing chain cover and some other associated parts. Not impossible, but makes for more work. The other option using an OEM unit is to put your own vent lines on it.

 

We finally replaced the opti, plugs, wires and water pump last weekend. What a PITA! All the advice on this thread came in handy. I cannot imagine what chevy was thinking when they came up with this design.

 

You will have to stick with Gen I Opti. To move to a Gen II Opti, you would need a new timing cover, a new cam with dowel pin, and a host of other things. Here is a good article if you want to "vent" your Gen I Opti:
http://www.corvettefever.com/howto/16758/index.html

And here is a link to a very well written article detailing the operation of the LT1 and inparticular, the Optispark:
http://www.gmhightechperformance.com...ing/index.html


This pic should answer your "timing" question. The drive shaft that connects the Opti and Cam is splined, so the Opti will fit only one way. You do not need to worry about TDC for re-assembly. The spline will ensure the rotor is positioned correctly:

 

You do not have to mark the rotor position when taking off the old (Gen 1) opti? You just remove and replace with new as long as you get the spline shaft lined up?