Well if you remember my thread from a couple days ago my car was acting weird. If not here is a reminder http://ls1tech.com/forums/showthread.php?t=736496.

Well my mechanic said its just missing real bad. I kinda knew that from the backfiring but still don't understand how it caused the popping noise I was hearing. And the check engine light never came on? He said the opti probably has oil in it and its "slipping" causing the miss. He says that because obviously he drove it and looked at it on the lift where he noticed a little oil leak from the timing cover. Anyway the opti has at most 10k miles on it and I don't wash my engine bay...EVER! So he says he will try to warranty the opti at the dealership and if they won't then he will replace the cap and rotor because the rest should still be good. My question is if we do just the cap and rotor should I do GM part, MSD part, or autozone/advance part?

Also this will be on my 94 T/A with a nonvented opti. Has anyone ever sealed their opti with like silicone or RTV? I'd be interested if this would work to keep out everything? Or would the vented MSD be my best bet? I'm just trying to get ideas for now because this coming week is when he will have time to tear into it and diagnose the problem for sure and whether or not he can warranty the opti for a whole new one.

 

If oil really did get in your opti, then it probably got all over the shutter wheel and pick up. Replacing the cap and rotor wont help much if at all. This to me seems more likely the cause of a backfire because the computer is misreading the cam position/timing and firing the cylinder late after the exhaust valve opens.

As far as sealing the opti, even if you could do it perfectly, I don't think you would want to do it. Even if it's sealed you are trapping the moisture or humidity that's already in the air inside. As temperature changes, that water is going to condensate on the parts inside and begin to corrode it or cause incorrect electrical contact.

The whole reason GM added the vented portion was to create vaccum and air flow to suck moisture out of there. Completely opposite from what you're trying to do. Honestly I would just consider a complete stock replacement, fix the oil leak, and call it a day. Also before I would commit to buying a new opti, I would take the cover off and look to see if it really did have oil in it and that your problem isn't elsewhere.

Good luck,

Chris

 

We haven't taken it apart yet but we will this week. He just suspects oil since its coming from the timing cover. Has anyone sealed an opti up?

 

Never sealed one, but I have a timg cover oil leak and it ruined an opti. Took it apart and there was a bout 3 TBSP of oil in it. Replaced the opti and we're good, takingthe car apart this weekend to fix leak. Mine is a vented opti, but oil can go funny places in these cars. My leak was below the opti.