They only last a month or 2 before they burn up. On this next one i will have new most everything(opti, coil, icm, Connectors, harness). I have not had the vented tube that goes to the manifold hoooked up, is it possible that that was causing the opti to overheat. Anyways guys, what i would really like you guys to do is make a list of everything that can possibly burn up an opti! Also this car does not get wet. Thanks.

 

TTT

 

Maybe your cam dowel is not the right length causing the bearings in the opti to fail? For the vented opti the pin should extend .620" from the cam and for the non-vented it should be .30" +/- .01. Might as well check it since your pulling the opti anyway.

 

Ya, last time it seemed like the heads of the three bolts that hold the cam gear on were to deep and it seemed like that might be putting pressure on it, so this last time i put a couple washers between the opti and the timing cover to exclude the possibily of any type of pressure causing the bearings to fail. But, it looks like it has happened again. I get plenty of spark coming out of the coil so i assume that everything is ok up to that point, but i don't really get much spark out of the plugs. My harness is brand new and i have tested all the wires from that point to my pcm. Do i just have really bad luck and these things are really going bad on me? Or is it possible something is causing this to happen? I need some really smart guys to think about this and try to make a list of what could make an opti fail like this and why it is making so much heat that it is melting my opti connector to where blue crap is coming out of it all over the place.

 

You really need to hook up the vent tube.

 

It will definately be hooked up this time. I just didn't think it would make a difference since the non-vented optis didn't have anything like this. Does the opti require some type of cooling from the vent tube that connects to the manifold?

 

Define "burn up". Not sure I understand what is happening. Is the bearing "burning up"? Is the optical module "burning up"? Are the cap/rotor contacts "burning up"? Is the harness plug "burning up"? Any actual flames involved , or are you really saying "wear out"?

Might help people diagnose the problem, if you can explain in more detail what is really happening. "Burn up" can mean a lot of different things to different people.

 

Everyone I see with chronic opti problems have done one or both of the following. Converted to genI sbc double roller timing chain. Converted to vented opti. That should tell you that cam dowelpin length is critical, .620/.685 for vented and .300/.320 for non vented. You need the vent lines hooked up also, they remove ozone and other contaminats caused by secondary ignition arching between cap and rotor.
Have you checked your ign wires with a mulitmeter? Do you have the correct heatrange plugs? Have you retarded your timing tables? Good luck on running down your problem.

 

Well i have done both. How can i measure the entire dowel pin with the cam gear and timing cover on the car? It shouldn't matter how long the dowel pin is as long as it does not bottom out in the spot for it on the opti, right? Because that is what would cause an uneven load on the bearing. The vent lines have been taken care of. I have checked all of my ignition wires with a voltmeter and they are all good. I am using autolite 106's which i think should be a stock heatrange. As for the retarding of timing, we would need to ask bryan at pcmforless.

Injuneer, when i say burning up, i mean that it is going bad. Although the connector that fits inside the opti is melting off somekind of blue crap all over inside there. So no actual flames or anything are involved. :P

 

yeah if your vented line is bad the vented optis go real fast, the original optis where sealed, when you seal an opti ozone isn't easy to create, that is why old airplanes sealed their magnetos(distributors) to prevent ozone, if they where exposed to atmosphere ozone was easily created by the spark (when spark happens & oxygen is present ozone is created) but even better solution since spark can still carbon track with time & create ozone even when sealed just that the process is retarded, best thing to do is vent the darn thing & prevent it from building up. Or even better go coil packs

 

I'll try one more time, then I'll stop bugging you. What part is "going bad"? Is the optical sensor failing (as evidenced by DTC codes)? Are there signs of burned contacts, carbon tracking, etc in the high voltage section? Is there any bearing damage? Is there rust buildup on any of the parts? Have you ever taken pictures of any of the failures?

By accurately describing what the inside of the case looks like, and the specific parts that fail, it might help determine the root cause. Maybe its just me, but "going bad" doesn't provide any more info than "burning up"....... .

 

IF....... "burning up" means that there is heavy arcing and/or carbon tracking that starts to cause a miss that gets worse quicly then may I suggest a change of plugs.

PLEASE do not run the stock A/C "dual platium" plugs. I have found they have a NASY habit of shedding the platinum puck off the side elctrode. Your gap then opens to .080" and everythign upstream in the ignition gets beat on real bad.

I gave up on platimum plugs in the LT-1 long ago. I use regular old copper plugs gapped at .045". THis simple change in my car and several friends cars made various "ignition eating" problems (opti, coil, coil wire) go away and never return.

BTW- the "vent line" has noting to do with cooling- it helps evacuate corrosive moisture from inside the opti. Earlier Optis (like on my 94) don't have it. Moisture and corrosion related failures take a lot longer than 2 months, though. I doubt whether having it attached or not has much to do with a failre in only 2 months.

 

I have seen a few cases around here were opti's go back. Comp cams has contributed to this problem. I have seen a few cams with the dowel pin too long. Yes the dowel still fits in the opti, but when the cam moves the clearance is no longer there and it destroyes the cap and rotor(it burns it up, melts the plastic). Im willing to bet your cam's dowel is too long.