After Market Opti Rebuild Kit, Is it OK? Do I have "Time" it?

[Timbers]

My water pump is toast so this weekend I am installing a new waterpump, and I figured I would replace the opti, since it has 56,000 miles on it. I am also replacing all of the seals, except for the crankshaft seal.

I had two questions regarding this.


I bought a kit from Advance Auto in Wisconsin here, to rebuild my Opti. I need to get the E4 socket to take the screws out, etc. Anyway, is this an ok way to go? The part and the electrical box inside of it look brand new, the rotor is brand new. I should be ok with this right? I heard some rumblings about people not wanting anything but GM brand new opti boxes.

Second, is there any timing that I need to do when installing this? From what it looks like, the pin on the cam shaft only fits into one spot on the opti, so as long as those are lined up, I should be fine right?

Thanks for the help guys! This project sure SUCKS, half my engine is torn apart and laying on the floor hah

...Tim

[droptop z]

i just changed my cap and rotor but dont know anyone who has installed the rebuild kit you got, as long as you index it correctly everything will be fine cause their is no adjustment to be made on the opti, it is computer controlled.

[Injuneer]

What do you mean by "rebuild kit"? Is it a complete "rebuilt" unit, or is it some sort of parts kit that you place in your existing housing?

As far as indexing the Opti to the cam.... WHAT YEAR IS YOUR CAR? You really need to included that info with your posts, or you could get some bad info. Not all LT1's are the same. There are many differences from year to year. Appears you have the one driven by a dowel pin (95-97). It this correct? As simple as it may appear to assemble the pin to the back of the Opti, numerous people have managed to screw it up. You must match the pin to the larger hole, but it can be (and has been) forced together incorrectly by many.

Courtesy of Shobox:

[Timbers]

Hey Fred

Hey Fred,

Thanks for the picture. Yes I noticed the that the dowel pin was in the larger of the three slots, the only slot that is different than the other two so it obviously goes there. I will have to make sure I line it up perfectly when I put it back together.

I have a 1997 Trans Am.

The thing I bought at the parts store is the metal portion of the Opti. What I mean by this is that it is the metal housing, with the big metal spinner, that connects to the indexed disc inside. It looks like all I have to do is take the inverted torx screws out of my old one, and transfer over the big black plastic housing with all the spark plug ports on it, the rotor and thats it.

Sorry for my non technical terms, but this new opti isn't like the complete unit that I pulled off my car. Its just the guts of the opti, looks simple to install, I just need to find a deep well E4 socket tomorrow morning!!

Heres a pic! The one on the right is the complete unit that came outta my car, the one on the left is what I bought at the parts store.


Thanks,

...Tim

[Injuneer]

So what you bought is the rear 1/2 of the Opti.... metal housing, with "rebuilt" bearing, bearing support, optical wheel and optical sensor, harness connector tower, and possibly a new rotor? And you will be reusing the "cap" portion of your old Opti.

Probably not the way I would do it. What was your problem to begin with? A failure of the optical section will set codes. Did you have codes for problems with the high and low res pulses? If not, why replace that part? About 70% of the problems in the Opti are with the cap and rotor. The terminals burn, you get carbon tracking in the cap, the rotor tip burns or the rotor disintegrates. There is also speculation that the high voltage wires internal to the cap (used to route the buttons to the correct plug wire tower) start to cross-fire when the cap loses its dielctric properties. Is is "speculated" that this can be accelerated by use of a multiple-spark discharge type ignition system, but I'm not 100% convinced on that part.

You might want to consider picking up one of the new MSD caps (it there have been shipped yet).

The alternative is the complete GM Opti for ~$210-220 from one of the online discount GM parts sources.

Have you seen this writeup/photos on the dissection of a vented Opti:

http://www.charm.net/~mchaney/optisprk/optisprk.htm

[Joe 1320]

To put this in perspective, the cap and rotor portion of the opti are the most prone parts for failure. These parts (in any distributer since I can remember) are what carry the high voltage electrical energy from the coil and distribute these to the individual plug wires. The optical portion and the bearing fail far less frequently. Many have replaced the cap and rotor portion and have been fine. Some have replaced that only to have a different portion fail in another 20K miles. The pricing of the vaious "kit" replacements often cost the same as a complete plug and play opti from a discount GM source. When mine failed, the local auto parts store had a couple of kits. The optical portion (which was crap compared to A/C Delco) and the cap and rotor portion. I think both kits together would have run me almost $300 total and a complete plug and play unit from GM was $189 plus shipping(96-97 vented opti). It appears that the whole plug and play unit is the most cost evvective and highest quality when you order it at discount pricing. Since you already have it apart, make sure you replace the cap and rotor portion or you will be doing it twice.

[Timbers]

Hey

I was replacing it as preventive maintenence. My waterpump fried and covered my opti with coolant. I always had a little bit of a stumble at high RPM, so I said screw it and figured as long as I have the water pump out I mine as well do the opti replacement too, just to be on the safe side.

I didn't know what I was getting into, since I never had an opti apart before. I didn't get a cap and rotor with my setup, so I will probably take it back today and see if they have a complete unit with cap and rotor.

You are right though, the cap and rotor with all the little terminals probably corrode away as sparks fly between then. I mean, thats why in the old days you replaced caps and rotors, to get new terminals. Replacing this optical wheel and sensor part of the opti is probably pointless right now. Its just a sensor that senses the 360 different light windows in the disc, if it works, then why replace it.

Ok, I will take the whole works back and see if I can get a whole unit. If not, I will order one online from a GM discount shop.

Thanks for the help!

...Tim

[BmXRacR96]

Hey

Timbers, i have a 93 lt1. i could not find the inverted torx anywhere to take apart the opti. but if you have an extra throttle body laying around or are careful enough not to mess up the threads. take one of your screws out of the plate on the top of the throttle body. hold the threaded part in vise grips (may want to use a piece of cloth around the threads so u dont crush them with the vise grips), And use the head of the bolt as the inverted socket. its not the correct way to do it. but hey it works and saves a few $'s on the tool.


Doug

[markd79ta]

I used the Cap and Rotor from Advance on my Roadmaster...works fine. I did this last year, and I put about 10k miles on it since then. My Opti had 150k on it at the time...I know, that is a ton of miles for an Opti. Incidentally, Summit carries the new MSD cap and rotor set for the Opti for about $50 more then the one at Advance.

If you want the actual inverted torx, you can only get them from Snap-On. There may be another source out there, but I never found it. The Snap On inverted torx socket is about $30 shipped. About $100 for the full set. Sometimes, you can find the set on ebay; and they usually go for about $60-$70.

Yes, the TB plate screw works well; just put the unthreaded tip of it in a vice grip. I did this instead of buying the Snap On tools; although, I am going to buy the Snap On set for later use.

[Blazer]

Hi guys Good news for everybody. You can get the E-4 socket from McMaster-Carr.1/4 drive E4 part number 53025a38 $3.19 Big bucks Hay Order 30 of them an sell them on E-Bay get 10 times your money back. Hope this helps Blazer