First off. I am a new Corvette owner. But a long time Corvette enthusiasts. Anyway. I'd like to gain some opinion on what is the best practice for tuning up my 1996 Corvette CE LT4. It has 147k miles. All original but very well taken care of in my opinion.it's got some normal ware and tear expected for a 20 year old car. Please provide any expertise knowledge on how to ensure I get another few long years out of it. And please don't say rebuild. Can't afford a full restore right now. Although that is in the future plans. Lol

 

Welcome!! I bought my '96 LT4 CE 3 years ago. Depending of what the maintenance records (if any) indicate, I'd recommend ( besides the obvious engine oil / filter, plugs-wires if never replaced): Air & Fuel filters; drain & replace with fresh antifreeze ( Remove knock sensors from engine block to get out the dregs) Trans & Rear fluids, Replace brake and clutch fluids. While on jack stands or lift: Inspect brake calipers / pads / rotors, exhaust system bolts, brake lines ( Driver side), fuel lines ( Passenger side) for corrosion other than minor surface rust. Then there's inspecting the steering rack, Engine oil pan, timing chain cover for signs of oil leaks.

Then there's the Opti / water pump situation. The water pump mounts above the Opti, meaning when the water pump seals go, it leaks coolant onto the Opti, which is a very bad thing. Although mine wasn't leaking, I replaced my water pump after threading the weep hole and installing a hose barb & hose on the new pump to divert the inevitable leakage away from Opti.

There are many, many knowledgeable members here with way more C4 experience than I that hopefully will add what I've omitted due to my limited memory.

In my case, I found that beer prior and during all this, and bourbon after, eases any reservations.

Enjoy!

 

with all but add the 02 sensors.

 

That was great information BBNJKEN. Thanks!

 

do the spark plug wires one at a time pay attention to the loomes

 

How does everyone feel about engine additives. I want to cleanse my LT4 before putting in some brand new engine oil. Look forward to the response.

 

do not do it. if you want bring it up to temp drain your oil and pour some fresh to rinse a bit while the plug is out.

 

Welcome to the C4's...

My $0.02 - when you get a used car with a number of miles on it - start off by changing all the fluids (Engine Oil / Trans Fluid / Diff Fluid / Coolant / Brake Fluid (especially brake fluid) and even the Power steering fluid). No telling how long some of them have been in there. The power steering fluid is tough to do a flush on - I just suck out the reservoir with a turkey baster, put fresh fluid in - run the car a bit, and repeat. Brake fluid is one of the most neglected fluids, and starts life out clear - when you're done flushing / bleeding the brake fluid - it should be essentially clear when it comes out of the calipers.

I'm not a big fan of oil supplements. If the oil looks horrid when you drain it, do an oil change, and change it again relatively soon thereafter. I HIGHLY recommend Synthetic oils - they take the heat better, they flow better at cold temps, and these days they don't cost a whole lot more than the dino based oils. (This applies to trans and diff oil as well.) Throw a new air filter and maybe even a new PCV valve on, and you've made a real dent.

As for spark plugs - they are not a whole lot of fun to do on a LT1/LT4 motor. Cylinders 2 & 4 are pretty easy - but cylinder 8 is a royal PITA (I've found the "best" way to get that one is from below). None of the Driver side plugs are a lot of fun. But - plugs are relatively easy compared to the fun of changing plug wires. Getting the driver side plug wires off the optispark cap, and routing the new wires - attaching them to the cap will likely cause you to use words that the FCC doesn't like to hear used on the public airwaves.... You might find that pulling the belt tensioner just to the left of the water pump makes the job a bit easier - but that tensioner isn't real easy to put back in place (ask me how I know this)... Depending on your level of mechanical competence, I'd recommend pulling one or two of the "easier" to get at plugs and seeing how they look before diving in whole hog and doing the entire set. The OEM plug wires are pretty good - so unless there is a good reason to change them - I'd probably leave well enough along - at lest for the time being.

I would HIGHLY recommend getting under the car and checking the outer tie rod ends for slop - there is a good chance that if they're original - they've seen better days. The easiest way to check that I know if is to have someone rapidly move the wheel right and left with the full suspension load is on the wheels, and you under the car with a flashlight looking for any relative movement in the tie rod ends.... While you're under there grease the upper and lower ball joints, and take a real good look at the shocks. The OEM shocks were Bilsteins, and they are very good shocks, but 100K plus miles is a long time....

The fuel filter on the LT4 cars is right by the pass side catalytic converter. If it looks like it's original - it may not be a bad idea to change it. It's not a real fun job - but you do get to smell like gas for a few days afterwards, and it does use good old fashioned threaded fittings - so changing it just requires normal line wrenches - not fancy line disconnect set that never seem to work quite right. Finally - pull the wheels and give the brake system a good looking over (do this when flushing the brake fluid / bleeding the brakes). The C4 brake system (particularly with the 13" rotors) is under rated - by many - but the calipers, pads & rotors all need to be in good shape, and not all cars with some miles on them are like that ... If the pads are worn - put a new set of pads on, and if the rotors are downright ugly (which can happen after 100K plus - new rotors aren't all that painful.


One final thing to say - NEVER EVER wash the engine on a LT1/LT4 car - as BBNJKen said - the optispark distributor on the LT1/LT4 motors doesn't like water - and if you wash the engine - you will almost inevitably get water on it - which is a very very bad and likely expensive thing....

GOOD LUCK & ENJOY !!!!

 

Removing the serp belt helps get into those tight spots on the opti. I removed the splash panel on the driver side, made getting at the plugs much easier. Also used an old straight spark plug boot works great for starting new plugs. Find a friend with small hands on #8!
Enjoy your new ride.

 

This was an outstanding post!! Exactly what I was looking for. Thank you very much. Whould you mind if I keep you on "speed dial". Lol

 

A number of years ago, I bought a 96 LT4 with similar miles (most of which I believe were California freeway miles) and based on my own experience these are the areas that needed immediate addressing:

(1) pull the valve covers. The roller rockers used on LT4 engines are a pedestal mount design which require no adjustment...in other words can't..be adjusted in the conventional sense...which is good, but they are also "self locating" or "self aligning" design and I found two that had drifted off the valve stem tips. One just required replacement on the valve stem, the other had it's locating "ears" damaged and required replacement of that individual rocker.

(2) while the valve covers are off (and make this easy on yourself, pull the spark plugs) rotate the engine by hand and verify / measure that all the rockers move the same amount...if they don't, it is a sure sign that you've lost one or more cam lobes; on my engine there were three bad lobes, all towards the rear of the engine. If so, on to step 3

(3) pull the intake manifold. Pull the individual lifters. any damage, pitting, or wear on the wheel of the lifter indicates a correspondingly bad cam lobe

(4) While the intake manifold is off, do yourself a huge favor and replace the oil pump stub drive; the plastic (nylon) housing cracks, breaks, and the gear on the end wears through the surface hardening and then it fails too; This was one of the dumbest idea's ever putting the oil pump drive where it is inaccessible and can't be pulled for routine inspection. If you don't believe that these little pieces of sh*t fail, google it. Do not trust the original. Just replace it, they're cheap enough.

So on my engine, rockers, cam and lifters required immediate attention. Yours may not.

(5) The Opti's on the late LT engines are very robust and trouble free, largely due to the positive vacumn ventilation system, something that earlier Opti's did not have. However the same cannot be said for the ventilation system itself. On mine the hose carrying air to the Opti had been cut by the serpentine belt and the vacumn hose going to the intake manifold was some form of soft rubber and heat and oil over the years had softened it even further causing it to collapse onto itself. There is no need to search out a stock Opti "vacumn harness"; ordinary (and more robust) small fuel line hose will work just fine, and since you can cut it longer you can reroute it away from potential damage.

(6) Replacing the Opti is a judgement call, it's expensive, but the Opti, like any distributor, needs a rotor and cap replaced on occasion, and I'm willing to bet that your's is at that stage.

(6) By this time you've already pulled the water pump, and I highly recommend replacing it with a new one.

(7) one of the stock multitek fuel injectors was leaking; I found this out when the car had set for a week and I checked the oil level and found it at the top of the dipstick. I replaced the oem fuel injectors with improved Bosch III injectors.

Everything else was pretty routine maintenance, change all fluids, all filters, especially the fuel filter on the passenger side frame rail; new spark plugs, new spark plug wires. New hoses. New serpentine belt.

(8) break out the old elbow grease and cleaners; Unlike the olden days, I DO NOT recommend using a pressure washer in the engine compartment.

And enjoy your car

 

This is great! Thank you!

 

Depending on it's condition you might consider replacing the weatherstripping as well. I did all of mine and it really wasn't too bad labor wise.

 

Yes she definitely needs new weatherstripping. I have found nothing under $400 for a complete set. Found anything cheaper?

 

Be patient and shop around. I found my set on Ebay about two months ago for $250 shipped to Hawaii. The whole set was brand new in bags.

 

No, you keep the stock fuel injectors they have the clip and will not pop off

 

It's been awhile, and I don't remember the whole durn process, but at the end, I do remember thinking "That was easy!"

 

I have added a few preventive maintenance parts to my 96 CE Lt4 with certain parts being costly or discontinued.
My top addition,
Cut the vapor return line from the canister to the intake behind the power steering tank and splice in a $1.99 viewable lawnmower gas filter.
This will not only protect your selinoid and purge value from a canister degrading but also trap any filter debris giving a heads up to a problem undetectable by the dealerships.
I came up with this after no dealer service personnel could diagnose my car correctly.

 

Hi Silverbullet
I have pics up of what I did with the vapor return line in a older post. Also if you have a Lt4 HD package check out the plugs I came up with too for the front calipers.
We have a great Vette in the 96 CE and I can't wait for spring so I can get out on the road again.

 

Only thing I'd add to the above is a new set of coolant hoses. Rad and heater hoses. Do this when you service the radiator and do a coolant flush with new thermostat. As said above, no pressure washer to the engine, simple green and a rag if you want under hood detail. No motor additives. Just come up with a budget and see what each project runs and do one at a time as allowed by time and $.