reservoirdogs12

I've got a '97 Trans Am with 155k miles on the clock. Everything ran fine the last time I checked, but with that magic number of miles, I'm planning to replace the water pump in the spring as well as do something with the distributor while I have access to it. I'm pretty sure both parts are original, so I'm doing preventative maintenance


Anyway, do you guys think I should just replace the Opti with a new Delco unit completely, or maybe just replace the old cap and rotor with a delco kit--I only bother replacing parts with AC Delco if it wasn't obvious by now. I am on a budget; however, I don't mind paying for the complete package versus the cap and rotor kit if its more logical, but in my situation it could mean another summer before I can afford all the parts for headers and a catback.

Since the opti still works with these high miles, would it be reasonable to assume that the optical sensor portion is in good condition and that a new cap and rotor could save me some bucks/tune up the ignition system, or would everything along with the cap and rotor in the distributor be worn at this point?

I'm reading about how some optis can last to 200K+ miles, and I sort of think I can reach this since I'm replacing the waterpump before it starts leaking.


Input appreciated.

ahritchie

iTrader: (1)

If it's lasted this long, I would just do the cap and rotor. You have the later vented style opti which is said to last longer than the unvented 93-95 optis due to not letting moisture get trapped in the optical sensor part. The cap and rotor are the only "wear items" I believe.

Uwilllosetomy93lt1

Do it!! It's time to replace the entire opti before "It" happens...

1963SS

Don't do it. Just change the cap and rotor. I used the MSD. The Opti on my Impala has over 250,000 miles on it and it's original. The Vette has 150,000 and it's original. The original sensors rarely fail.

Uwilllosetomy93lt1

....and probably doesnt run as well as u think friend. It MAY seem to run good but, the electronic optic's do degrade over time and eventually starts to miss the timing window spark gradually. So, for performance and proper timing, change it. Not really after power, keep it like this fella....

Gojira94

iTrader: (4)

It's been my experience that the shaft bearing will crumble before the J924 encoder will die. Pull it off and inspect it if you're already in there for a cap and rotor. It should feel smooth with no notchy feeling to it when you turn it. If it looks good then go for a cap and rotor. And most will advise a touch of thread locker on the rotor screws while you're there.

Uwilllosetomy93lt1

Some do, some dont. Cap and rotor are still preventative maintenence, NOT to be confused with full opti replacement. DD can afford to push the limits of the sensor, just to get u back and forth. However, it's always a good idea to replace entire unit if your over 100,000 miles. If the pricing on these units were fairly cheap, I am willing to bet that ALL of us would replace the entire unit, instead of the cap and rotor, right? Hate to go through the entire job, then having the unit go out 1 month later.

93 LT1 Vette

Take it down and inspect it. Mechanics rule number one is. "If it ain't broke don't **** with it". But in the case of the evil opti it's even money. During my cam change I did the opti, cap and rotor 3 months ago. I said to hell with a new alternator and belt. Last week I crapped the alternator and it snapped the belt. Problem solved.

1963SS

Uh.....it runs OK and nothing shows up on the data log. The only thing that I do is whenever I change the cap and rotor I do clean the sensor and the wheel. Clean optical sensors are pretty much digital. Either they do or don't work.

BTW, it weighs over 4300 pounds and last time out it did 11.78 @116. I drove 600 miles to the track and got 21.5 mpg with a trunk full of slicks, a suitcase, a cooler of beer, 8 quarts of moonshine and three fine friends in the car. I know that's not fast by F-body standards but the ole' Impala SS is really a pig. Many of you guys can blow me away but that's OK. I can make out with a real fat chick in the rear seat without being dog knotted.

Catmaigne

iTrader: (6)

"If it ain't broke, don't fix it."

Assuming the optical sensor has never seen much moisture, it should good as new. They will go the distance if sealed properly. Open up your current opti and check for oxidation/rust. If everything checks out just replace the cap and rotor.

leadfoot4

iTrader: (1)

I agree...

Being an "old school" kind of guy, who's used to easily swapping out a distributor cap on top of the engine, I always thought that those items were a 2 year deal....replace it every 2 years. Obviously, swapping an Opti cap and rotor isn't quite as easy.

Having said that, I swapped the cap and rotor on my Z-28 when the car had around 40,000 miles, and was 6-7 years old. It was running just fine, but I strongly believe in maintenance. What I didn't realize at the time, was I could leave the Opti bolted in place, and simply replace the cap and rotor. I took the entire unit out to do the job. I say this, because 35,000 miles later, shortly after I replaced the cap and rotor a second time, I heard a strange ticking noise coming from the Opti.

I took the Opti out, and found that the bearing/bushing, whatever it is, had crapped out, and the rotor was wobbling all over. The noise I heard was the tip of the rotor brushing against the inside of the cap. I'm now thinking that if I had left the Opti housing in place, the first time I replaced the cap, I wouldn't have disturbed the bushing, and possibly it would have lived longer.

This is one time where if it wasn't broken, I shouldn't have tried to fix it....

Jr.Samples

Just changed my complete opti. After taking it off to replace the front seals I saw there was some loose play in the opti shaft. I also notice there was a growling noise when I spun it.

It has 158K and believe this to be the original one.

I think I dodged a bullet on this one.

whytryz28

iTrader: (28)

Delco Opti + MSD cap and rotor

food nd cars

This.