I recently replaced the opti in an F-body. Customer stated the car would run rough and misfire. First thing I noticed was a brand new upper radiator hose. I put the car on the lift and there was coolant residue everywhere. Whoever put the NAPA hose on did not drain the coolant first. Our corvette specialist (Jeff) has an LT1 Camaro so he usually also does all the Camaros, this was going to be my first opti, as well as intake (oil leak) and plugs.

When I got the distributor out, Jeff came over and was surprised that the bearing wasn't making noise as they usually do after being soaked with coolant. Curiosity got the best of us, so the it had to come apart and here is what we found:

This first pic is just in all the pieces seperated, cap, rotor, and main electronics. Very few people seem to know this, but the cap and rotor are actually serviceable parts.


Here you can see that oil contamination was the more likely cause. There is a little driveshaft that connects the center to the cam drive which goes through a seal. In this case, that seal was more like a screen. There is better pic to follow, but that disc in the center has the marks for counting rotation, the high resolution and low resolution signals which are compared. (Check your DTC list, code 16, 41)


Her's a great shot of what your opti does, simply counting the outer marks on the ring while monitoring the "holes". As you can see in this case, those holes would be covered by oil on occasion and therefore the PCM would lose track of where the cam is. It had no idea what to do, it needs to see four holes for every 360* (the lines on the outer part of the disc) of rotation.



Just thought I'd share some interesting photos, so at least you know what your paying $650 plus labor for. Alot of you out there have these and it's always fun a get a better understanding of what's going on under the hood.

 

Cool, thanks for sharing. Had no idea the opti cap and rotor were servicable :crazy:

 

Thanks! Excellent post!

I would say from looking at the pictures the whole damn thing is servicable! Just clean it up, replace the seals/bearings and put it back together. :)

 

My advice is a little different from Atok's. Replace the whole opti. Are you sure you can replace the bearing and seal? Can you really get it clean enough? Why not start out with a new one. Mine had a lot of rust and once that wheel is rusted it won't be long until you're in there again. I know I sound like a broken record, but I'd get rid of that OEM water pump and go electric; it eliminates the weep hole leak on the opti and does away with one source of a possible oil leak. :chevy

BTW, I wish I had these pics for my Tech Tip Article. Thanks for the post.

Oh, I'd vent the opti like the 95 -96 LT-1s


[Modified by Strick, 8:27 AM 7/25/2003]


[Modified by Strick, 8:28 AM 7/25/2003]

 

Yesterday I took my old opti all apart to get a better look at it. The disc with the holes seems to have a tiny spot weld or is punched to the rotating plate behind it. It does bend when removing it and I'm not sure how you could reattach it properly. Once this is off you can get to the back of the housing. The electronics (connector optical transmitter and reciever, etc.) all come out as a unit. If I knew how to post pics I'd do it. BTW, took the car out for an hour run last night (sometimes to 6000 rpm) and no fluid drips on the garage floor this morning. :hurray:

 

Yeah, you can buy the cap and rotor kit from NAPA for about $150 or so. Been there, done that. Won't be doing it again. The seals and bearings have issues as well. I'll be getting a GM unit here soon. At least they are good for about 50-70K. I can deal with that. :smash:

 

Ain't that a great feeling, knowing that you don't have any oil leaks? Great job. Now, what's next? :grouphug:

 

There is a good article on optis in one of the new mags out. GM High Tech Performance - I think.

 

What's next?? :steering:

 

Good info, thanks bro..........

:thumbs:

 

Thanks Chris, this should be a must read for all LT1/LT4 owners. http://www.gmhightechperformance.com...htp_optispark/ :steering:

 

That was a very interesting post. Thanks for the info.

 

Which seal failed that let the oil get inside? Can a timing cover seal failing allow oil to get in the opti like that? The reason I ask is this: March 2002 (approx. 7000 miles ago) I had the opti and water pump replaced in my '95 , due to water pump weeping coolant over a long period of time and causing opti troubles. There is now a very slight seeping of oil going on somewhere up front such that the front of oil pan is oily and it sometimes blows enough back to form a small droplet on the oil drain plug hex head. Any guesses which seal might be letting the oil weep like this? No driveability symptoms, drives fine. I heard where if when replacing the opti if a certain three seals are not all three replaced such a leak can develop soon after.

Three weeks left on my GMPP, going to hit them up to repair this leak anyhow, just thought I'd ask a tech first. :)

 

:iagree: :seeya

 

Yes, the seal between the opti and the timing cover can leak. But my guess would be the seal to the water pump. If the bearing were going bad on the pump it will allow a bit of wobble and could damage the seal.

You can try to get a small flashlight in there between the waterpump and the timing cover to see if you spot any oil.