Converting to a vented opti

[94 formula]

My opti has been acting up lately and I've been thinking of just converting to a vented style one. I have a friend who just replaced the opti in his 95 caprice (used to be a cop car) and it blew up this past. I've heard that the caprice's had cast iron heads and a few other differences but could I use his opti and some other parts from his car on mine or is there a difference in between the lt1 in our cars? I know not to reuse his timing chain or anything like that but doesn't the timing chain cover and a few other things have to be swapped?

[Injuneer]

Here's a list of required parts, and "how to":

http://para.noid.org/~muttvette/opti.html

I don't know the specifics of the Caprice in question, but it might get you headed in the right direction.

[94 formula]

Thanks for the help. I think I'm just going to replace my opti with another non-vented I didn't know it got into that much money and my nonvented held up 106k. I would love to go to vented but am saving for college and would like to slap a set of headers and an intake on the bird before I leave.
One more question though when an opti goes bad will the computer go to a default setting for it kinda like when you first start the car and your in closed loop.

[Injuneer]

The car starts in "open loop". It doesn't use any sort of default... it runs exactly as it does in "closed loop", but does not enable "learning" on the long term fuel corrections. That's the only difference between open loop (cold start) and closed loop (fully warmed up coolant and O2 sensors).

Depends what part of the Otpi "dies". If its the high voltage section (cap and rotor) there are no codes, and the PCM does not know there is any problem. It just starts to miss and run eratically, and keeps getting worse and worse. The PCM will respond to the misfires as a "false lean", seeing the unburned air coming out of the missing cylinders, assume its running lean, and pour extra fuel into the injectors, causing it to run pig rich and miss even more.

If its a problem with the optical section of the Opti, it will set two different codes. DTC 36 will indicate loss of the high resolution pulse pattern, and the PCM will simply operate from the low resolution pulse, losing a small amount of ignition timing accuracy. You will not notice the difference. DTC 16 would indicate a loss of the low resolution pulse, and the PCM shuts the fuel pump and injectors down, since it can't properly time the sequential injectors to the correct cylinders without the low resolution signal. Engine stops dead. You're stranded. No "limp home" mode.

[pete]

You can change to a vented opti by going part of the way with the above link. You can take apart and clean your opti, and then replace the cap and rotor with a vented cap and the GM vent hoses.

I then took the opti base and pluged two of the three weep holes at the bottom (I used small rivets). I then drilled one of the weep holes out to 3/16" and installed a 3/16" plastic elbow for the second vent hose to attach to. Reassemble and you are set without changing the timing cover, chain, gears, etc...

Since its apart, I also drilled the weep hole on the water pump, installed another 3/16" plastic elbow and took some hose to route the eventual leak away from the opti. I routed the hose behind the opti and tied it off to the steering rack in a noticable spot, so when it leaks, you can see it.

There ya go!