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After a long search I've finally brought my first C3 home! This Forum has been a huge help in finding answers to questions of different years, options, and things to look for throughout my search... so thanks. Now that I've actually got one in the garage I have a TON more questions but I know using Search will by my first and best option. I've restored a few cars in the past but this is my first Corvette so I'm really excited.
My new addition is an 81 and has been with the PO for 23 years. It was always garaged and covered which is the good news. Frame is great and the car is almost totally original with the exception of a really good (in my opinion) repaint sometime before he bought the car in 1997. The bad is she wasn't driven much at all, especially in the last 7 years. Mostly just pulled out and a lap around the block at best.
I'm going to tackle all fluids, go through belts, hoses, fuel filter, etc. There are some small issues like tach and wipers not working which will be fun to troubleshoot. I'm going to go through the brakes and do the exhaust.
Plans are to drive it and enjoy it. Build a nice little 355 or 383 for it in the next year or two but keep it pretty clean and stock looking under the hood.
One of the first orders of business will be to understand what smog equipment I can remove (currently no belt on the smog pump) and keep for later if needed for any reason.
Any other suggestions for initial things to check or focus on by those who know these cars best are certainly welcome.
Hi K,
Well!
That looks like a really nice car in the photos!
You must be pretty excited to have it in the garage.
Good Luck.
I hope it gives you lots of pleasure.
Regards,
Alan
My first vette was an 81 Auto. I ended up selling it for a 93 6-speed because I rally wanted the manual shift. My 81 was bone stock, and was a complete dog. The 3-speed auto certainly didn't help.
I told you that story to tell you this one... Came back to C3s this fall with a purchase of a 78 4-speed. It had a Goodwrench 350 swapped in at some point, pretty much same power level as stock. I am not a high speed racer by any means, but felt the car still was fairly pokey. Went thru tons of info here on the forum, asked a bunch of questions both online and off.
I found terrific results by following Lars' timing manuals. I believe the 81 might have started with the computer controlled ignition, you'll need to verify. If so, try and find a way to bring more advance into your timing curve, including swapping in an older HEI or aftermarket distribute if needed. The throttle response and zip in the car was unbelievable after getting the timing dialed in. It made me wonder if I sold that 81 short, not trying to properly tune it up first before selling it on.
Ater doing the maintenance you mention, dial in the timing. You won't regret it n
Not sure about the 81, but the tach on my 77 started acting up recently and after some searching here on the forum, I found that it could be the tach filter. I bypassed the filter and started the car and the bounce seems to have gone away. Search the forum for "tach filter" before you go to the trouble and expense of a new board!
Nice Vette, welcome to the forum. Agree on your list; when I got my 78 under similar circumstances first thing was the brakes. If you buy calipers, make sure they are stainless sleeved. Did not do that with the first set, and when I painted/replaced the engine, the stock replacement calipers leaked (took about a year for engine/paint).
Mike
I cannot tell if it is black or some kind of charcoal gray, but it is a very nice looking car.
Since I own a black C7 (and previously owned a black C5) I will tell you a little secret if you promise that it will not go any further. Black cars are actually a little faster. Even if his is charcoal gray, it is close enough to black to qualify.
Congratulations to Khibbs on the purchase of a nice car.
Congratulations and welcome! That's a sharp looking car. I sure wish I could find power sport mirrors at anything near a reasonable price to add to my '79!
Before you remove ANY emission control equipment be absolutely certain that your state (Massachusetts) does not require emission testing in order to license the car for street use!!!!
Provided you are allowed to remove/modify emission controls for a street driven car of this age in your state you should still proceed cautiously. Believe-it-or-not it wasn't the emission systems themselves that turned these engines into comparative dogs--it was the engine tuning and other parts required to make the emission systems function properly. Most of the emission systems in your '81 still exist in today's high performance cars--it's advanced computer control (especially highly accurate nearly instantly operating feedback systems) that allow great performance and greatly reduced emissions.
A good thing about '81 is that you got improved (lighter and freer flowing) stainless steel exhaust manifolds and a more freely flowing catalytic converter. A potentially bad thing (for your car) is that with the A.I.R. (smog) pump disconnected raw unburned fuel has been entering the cat (if it's still installed) which causes it to overheat, loose effectiveness and worst of all clog. Provided you don't have to have a functioning (or present) catalytic converter consider removing it and installing true dual exhaust.
The A.I.R. (Air Injection Reaction aka "smog pump) system actually takes very little engine power and since I'm nearly positive it is bypassed during wide-open throttle any power reduction is least when engine power is greatest. It does a good job of burning off any unburned fuel in the exhaust. I'm far from an eco-freak but in my mind the A.I.R. system benefits outweigh the performance reduction.
Your stock dual snorkel cold air intake system is an excellent design and more than adequate for any reasonable engine you can put in the car. Functioning properly it aids warm-up and has absolutely zero negative affect on performance.
The EFE (early fuel evaporation) system also functions only during warm-up and unless you're working on track car where you want to remove every possible ounce of weight there's no reason to remove it.
The EVAP (evaporative emission control) system also has zero affect on performance yet it prevents fuel from evaporating into the atmosphere. There is no reason whatsoever to remove it and in fact it should be maintained to keep it working properly. I'd be willing to be that the associated hoses are due for replacement as fuel vapor is particularly hard on "rubber" tubing. Doc Rebuild sells excellent hose kits for EVAP and every other system of your car. While on the subject of hoses any original hose (with the notable exception of HVAC control lines) are probably due for replacement. They make look and test fine but the ends tend to stretch out over time resulting in little leaks at every connection. Some hoses are long enough to cut off and inch or so from each end--others aren't. Again, Doc Rebuild sells GREAT replacement hose kits with perfect diagrams to guide you.
While at least partly an emission control system, PCV (positive crankcase ventilation) MUST be working properly to prevent engine damage.
A definite negative with regards to "waking up" an '81 are the one-year-only CCC (Computer Command Control v.1) system and the strange electro-mechanical carburetor. While the system helped reduce emissions and increase fuel economy it decreased engine power and performance. While it worked well when new it did not age well due to a lack of feedback. I had an '81 Camaro Z28 with that system and nearly identical 350 and even at five-six years of age the CCC system was causing problems. As long as the CCC and dedicated carb and distributor remain I believe there is extremely little you can do to increase engine performance/power.
The CCC system was so troublesome and performance robbing that it was often removed. In fact you can reduce performance by doing things like disconnecting/deactivating the A.I.R. system! Look for an electrical connector going into the front of the carburetor itself. If not present there's a very good chance the CCC has been deactivated and associated components replaced. Also see if a catalytic converter is still installed. A replaced distributor could even explain your nonfunctional tachometer.
If the CCC is gone and the carb and distributor suitably replaced there are a number of things you can do to restore the "lost" power and performance. The #1 thing to do is eliminate vacuum leaks! Getting rid of the leaks is mainly about replacing most or all of the huge number of vacuum hoses. True dual exhaust will certainly help. The timing suggestions by Lars (previously mentioned) will do wonders. The cam used in previous L82 engines helps as well. From what I read here that cam is still a common grind for increased power with good street manners in crate 350s.
Your non-functioning windshield wipers may be due to a failed interval delay timer. It's a different module than used in my '79 so I don't know how to trouble-shoot but am sure you can find instructions by searching. I believe it is installed in the center console ahead of the shifter.
I forgot to mention EGR (Exhaust Gas Recirculation). EGR is likely the most contentious emission control system. Some say it has little to no effect on performance; others say it significantly decreases performance. Again engine tuning and other component design may account for more performance reduction than the system itself. The purpose of EGR is to reduce the oxides of nitrogen that result when fuel is not completely burned. It is an effective emission control system that is still used in every new vehicle. I believe that EGR is disabled with wide-open throttle so you might keep that in mind before you remove/disable the system.
Might I suggest that you post some pictures of your engine, carburetor and distributor? Many a new owner to an old C3 is surprised by the changes that have been made to what looks like a "bone stock" car! Some of those changes can be so old that they do look original.
While everything hinges on your ability to street license an emission modified '81 in Massachusetts you might consider backing off your stated desire to drop in a different engine.
Regardless of how stock your engine is I cannot give higher suggestion to replace all of the vacuum hoses in the car.* If you don't already have one get a hand vacuum pump like a Mitee Vac! They're cheap and of incredible use in our cars! You'll spend less than $100 replacing the hoses and like me, may be floored by the amazing improvements in performance, starting and even comfort. This includes getting all of the emission control systems working to include A.I.R--even if you don't have a catalytic converter. Don't forget the hoses (and filter) going to the brake booster and the little piece of hose installed at the transmission for the modulator valve.
*before replacing the small vacuum hoses used for HVAC simply disconnect the system at it's funky "T" at the driver rear of the engine between the distributor and brake booster, pump down with a hand vacuum pump and see if it holds vacuum overnight. It very likely will as these hoses (and their connections) are different than all others in the car.
If not already done and, again, allowed in MA, consider disabling the CCC*, swapping the carb out for one used in a '78-'80 and replacing the distributor with the basic HEI (pointless) version.
*the CCC controls your lock-up torque converter. I don't know how much of the system can be removed before the lock-up ability is lost. I do know however that this early lock-up system tended to engage and disengage so frequently and noticeably in city driving (especially with hills) that some people intentionally disabled it long ago.
Remove the catalytic converter, pipe for true dual exhaust, put in a higher performance cam (again the one used in L82s is a good choice), set timing per Lars instructions and you might find zero need to replace the engine.
Your '81 has the aluminum differential case and mounting often referred to as the "bat wing". While a significant weight reduction compared to the cast iron version that it replaced it is not as robust. The cast iron unit was able to handle anything the pre-emission, high compression, high performance big blocks could throw at it but the aluminum version was never designed to handle that much power. I do not know how much power you can add before you can expect problems.
Thanks for all the replies. I'm extremely excited about digging into the car. The color is a charcoal grey (almost black fast) with a little metallic in it. Absolutely love it and I haven't even given a good cleaning and detail in the photos you see posted here.
MA doesn't require that I keep any emissions equip so I' pretty much free to do what I want and makes sense for the way I plan to use the car. SwapmeastMike, thanks for all of the detailed information on the equip. I wanted to remove some just to clean up the engine bay a bit but I'm not opposed do keeping things that make sense. I know she isn't going to be winning any drag races with the current engine and that's fine with me. I'll have to identify each of these systems under the hood and then I can see about what to remove and which ones I'm going to test and replace hoses, etc so they will function properly. I have heard about changing the ignition timing curve which is supposed to help.
It has what I believe is the original exhaust system with a HUGE cat under it now. One of the first things I'm doing is going to a true dual system without cats.
I've read about the CCC cars and it sounds like the best option for me might be to replace the carb and dist for the short term. I'm sure a properly curved HEI will really help. I just need to understand what else needs to be done to facilitate this swap. I believe I read there is also an O2 sensor or something that feeds the ECU and will need to be addressed or you will have a CEL (Check Engine Light).
I have ABSOLUTELY NOTHING to back this up but just from looking at the engine bay it looks 100% stock. I removed the connection from the snorkel to the passenger side airbox system to clean it out for these photos but there isn't a cut wire or anything I can tell that's missing. Just ordered the shop manual but as far as I can tell I'm starting with a totally stock setup.
** If you look closely in the third pic you can tell I need to replace my cross cable for the hood release. Thing is about ready to go!
Can you post some photos of the carburetor with the air filter removed?
The CCC v1 system was extremely primitive and I believe that swapping the carb and distributor with '80- units will remove all computer control from the engine. Again, I do not know what happens with regards to torque converter lock-up but I am certain there are reasonable ways to both retain the lock-up ability AND make it less obnoxious during city driving.
Considering that your A.I.R. pump belt is removed it would not surprise me at all if your check engine bulb has been removed.
New owners to our cars are essentially forced to become crime scene investigators no matter how original the seller claims it to be. I say "crime" not because I consider all modifications/workarounds to be bad but because it requires close examination and even forensics to determine what has been changed since the car was built.
02-19-2017, 05:25 PM
My First C3! Here we go....
