contraststriker

iTrader: (14)

1995 Trans Am
- high lift cam
- electric water pump
- Summit double roller timing chain

at 145k I blew the car's original opti. I replaced it and this opti died in another 150 miles...one interesting thing after this install: I heard a periodic grinding from the timing cover area, as if part of the timing chain assemply was scraping the timing cover despite the fact that it hadn't for 5000 miles since its install. I have a Summit true double roller timing chain, so it did require some clearancing on the timing cover. I suspected that a bolt had loosened from the timing gear and thus timing cover scraping had somehow caused an oscillation which blew out the bearings in the brand new opti, so I replaced it with another opti and tightened all bolts with loctite. At that point I also installed an MSD blaster coil, though I doubt this alone without an MSD 6A or 6AL could destroy the opti quickly. That opti lasted 1400 miles until the present--the T/A died again Saturday. It started out as a very high miss, then worked its way down to all RPMs except idling. The car stutters and backfires like crazy, won't go anywhere--I'm sure it's the opti again.

So...any hypotheses about what keeps destroying my optisparks? What sort of destructive oscillations can get transferred to an opti? It really seems like the cam pin is awfully solid with no play, so how could it be killing optis? It's especially strange that for 5000 miles post-double-roller-install the opti was fine, then it finally died. And it IS the innards of the optisparks that get toasted...when you remove one you can hardly even rotate the metal cam pin acceptor, and if you can tons of junk rattles around on the inside. I am desperate for help on this problem, as I have given the car to a higher-end local auto shop in hopes that they can find the root cause...I'm afraid this may be over their heads though. Thank you SO much for replies!

Low N Slow

iTrader: (4)

The drive pin in the cam being too long could cause what is happening to your optis. You may have to cut it off a bit so it's not putting any pressure on the opti when you install it.

contraststriker

iTrader: (14)

so has the pin somehow worked its way out toward the opti? I mean, it was fine for 5000 miles of this new cam, then boom. Now they won't last more than 1500 miles. And I bought the Comp Cam for a 95 LT1, so it seems like they'd know what length to make the pin...

TwoFast4Lv

iTrader: (8)

IF the Opti hole in the cam(95-up) is not drilled correctly this can be an issue.

Your present problem just sound like you burned the cap and rotor with Carbon tracking

Good luck!

contraststriker

iTrader: (14)

I burned the cap and rotor in 1400 miles? Sounds unlikely...

buffman

iTrader: (9)

actually they do and they dont. I thought they included a card that reminded you to measure the dowel pin to insure it was the correct length.


IIRC I think the dowel pin length should be 5/8" long after being pressed into the cam.

Z28&WS6

iTrader: (5)

yes, sounds like possiblly the cam pin is too long. you do have to check them. i ground a good bit off of mine to get it to fit. maybe the first opti lasted a while before it tore apart. def. get the shop to check it out though.

redhot lt-1

iTrader: (2)

lownslow is right i had the same problem with one of my optis because of the cam drive pin get some assemble wax and test fit the opti and cut the pin until you have some clerance then you shuould be good to go

buffman

iTrader: (9)

Pin should be cut to specified length in order to insure proper operation. Did you replace the Cam sprocket bolts when you did the install? IIRC the ARP ones have a slighlty taller head than the stock ones (at least from waht I remember) and could be causing an issue.