Impala Forums banner

1 - 6 of 6 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
Hey guys I'm new to the forum. I have a 1994 355 LT1, I bought the car years ago and it's been sitting ever since now I'm bringing it to life!*

Is the LT1 engine reliable? Should I replace the Opti-spark? I was researching and some people said it's very unreliable and some say it's been improved. Should I keep The LT1 engine or should I engine swap to the 6.0 LS engine for more of a reliable setup? Thanka
 

·
Super Moderator
Joined
·
3,939 Posts
Answer really is "it depends" a well modified and cared for LT1 can be great with awesome lowend. A lot of them were crappily modified though.

Opti is a good piece BUT is often neglected and then when it fails due to neglect they bitch that it is a bad design.
It is a hassle to change and cost more than a traditional cap and rotor so people neglect this basic tuneup item.

If you decide to stick with the LT1 which is reasonable unless you find something that says it is junk then order an opti or just cap and rotor for a 95. The Caprice/Impala/Roadmaster/Fleetwood got the later vented design in 94 a year before the Vette and F-body and this causes some parts catalogs to be wrong so if parts wise you tell them your car is a 95 it just makes things easier.

Do you know anything about the 355 or anything else done to the car?
 

·
Registered
Joined
·
6 Posts
We have a 95' Caprice 5.7L. 91k in 01' when bought from a salvage yard. It now has 178k. It overall has been a very good car. Reliable. Only modification has been a K & N filter. 25mpg avg. highway driving. Still hard to get in todays newer cars.

The OPTI spark distributor was designed as GM was advancing computer design - per full fuel injection - per electronic spark design. Somewhere in the middle for a period of 4 years were the opti spark. A flat pancake large oval distributer. turned in back of the water pump buy a metal coupler sealed from each other by O-rings on each end of the coupler. This makes it undesirable only because the O-rings wear out and thereby oil and water leak out from each end of the coupler. I have not replaced mine since the 120k timing chain replacement and don't quite remember if the coupler is driven from the cam and front of the timing chain cover. I don't recall correctly.

I then used a ACCELL Opti-spark Dist. and an ACELL coil. I also changed the spark plugs and wires. The wires are fed from the bottom of the opti spark dist. by 4 each on the bottom left and right of the distributor. Kind of odd, but its the best I can explain.....


Even though the engine produces only 180+ hp, it does get out of its way pretty darn well. Since its my wife's car, it is fine. It loves carving up the mountain's. I have gotten a speed ticket and warnings galore from the wife to slow down.....I am now disabled and still want to update the engine and keep the car..... We have kept up all other maintenance. Does not smoke. We use Mobile 1 Synthetic and 100% fuel.
 

·
Super Moderator
Joined
·
3,939 Posts
Inside the coupler is dry, maybe a little grease but no fluids, it can wear out and is driven by the cam.
Why change a timing chain at 120K miles, these will go at least 2 times that, timing chain is not a maintenance item on this motor as it is on some engines.

Far as HP the 4.3l version called the L99 was 200hp and the LT1 was 260hp/330tq at a very low rpm. The LT1 feels snappier than an LS3 because it makes torque sooner and doesn't have the intrusive torque management of later motors.
 

·
Super Moderator
Joined
·
3,939 Posts
If assembled properly it should be fine, acting up when wet may be a sign it is getting worn out or that the vent harness or plug wires or something has failed.

If it hadn't been driven recently and was raining and wouldn't start then the distributor itself is dry, got a giant hood covering it. If the cap is old and worn humidity can cause spark scatter, or wires could be arcing, not starting I would be looking at the coil wire arcing in humid conditions.
 
1 - 6 of 6 Posts
Top