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Old 03-30-2013, 10:38 AM   #1
Blame
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Default 81 model vette

Can i get some of the vets of the vettes to give me a run down of the 81 vette? Need info like what package is what, what is the base model vs it fully loaded model. How and where to look for trouble areas that maybe on the vette. And how hard is it to replace a cruise control switch. If im going to keep this vette i best know what im getting myself into.
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Old 03-30-2013, 12:28 PM   #2
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The cruise control lever is discontinued. No one has offered a reproduction yet. I have only had my '81 for one year so I wouldn't call myself a veteran. I have done a lot of work on it though. Brakes, rear trailing arms, transmission, weatherstrips, etc. I'm about to replace the rear end after I get it back from tracdogg2. Replacing 2.87 and going with a 3.55 ratio.
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Old 03-30-2013, 01:45 PM   #3
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The cruise control lever is discontinued. No one has offered a reproduction yet. I have only had my '81 for one year so I wouldn't call myself a veteran. I have done a lot of work on it though. Brakes, rear trailing arms, transmission, weatherstrips, etc. I'm about to replace the rear end after I get it back from tracdogg2. Replacing 2.87 and going with a 3.55 ratio.
It more info then anyone else posted.
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Old 03-30-2013, 01:58 PM   #4
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Quote:
Originally Posted by Street Rat View Post
The cruise control lever is discontinued. No one has offered a reproduction yet. I have only had my '81 for one year so I wouldn't call myself a veteran. I have done a lot of work on it though. Brakes, rear trailing arms, transmission, weatherstrips, etc. I'm about to replace the rear end after I get it back from tracdogg2. Replacing 2.87 and going with a 3.55 ratio.
Street Rat I did the same with mine I went with a 3.54 you will love the change but if you do any highway driving you will see much higher RPMs.

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The 81 has many 1 year only parts such as the CCC this was first introduced in 80 for California only and std for all '81 vettes the '81 had only one engine option L-81, it was the last corvette with a carb it has the 350THC the introduction of the composite mono spring with the exception of the Manual transmission that still has the steel leaf spring. I guess those are the main differences between the 80 and 81. As for the differences with the '82 the main difference is in the engine (L-83) Introduction of the cross fire fuel injection and the 700R trans also the 82 only came in automatic. for now that is all that comes to mind ... one more thing in '81 the corvette was manufactured in to plants St. Louis until the end of July 81 and Bowling Green that started production in June.
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Old 03-30-2013, 03:19 PM   #5
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Street Rat I did the same with mine I went with a 3.54 you will love the change but if you do any highway driving you will see much higher RPMs.

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The 81 has many 1 year only parts such as the CCC this was first introduced in 80 for California only and std for all '81 vettes the '81 had only one engine option L-81, it was the last corvette with a carb it has the 350THC the introduction of the composite mono spring with the exception of the Manual transmission that still has the steel leaf spring. I guess those are the main differences between the 80 and 81. As for the differences with the '82 the main difference is in the engine (L-83) Introduction of the cross fire fuel injection and the 700R trans also the 82 only came in automatic. for now that is all that comes to mind ... one more thing in '81 the corvette was manufactured in to plants St. Louis until the end of July 81 and Bowling Green that started production in June.
That is useful info. What would it take to get good mpg from a 81?
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Old 03-30-2013, 04:58 PM   #6
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a trailer to tow it on? 200r or 700r 4 peed auto would help. maybe change the gears in the rear end? dont press down as hard with your right foot? lol
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Old 03-30-2013, 05:28 PM   #7
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a trailer to tow it on? 200r or 700r 4 peed auto would help. maybe change the gears in the rear end? dont press down as hard with your right foot? lol
What kind of rear end gears should i look into and how hard is it to add a manual tranny?
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Old 03-30-2013, 05:43 PM   #8
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What kind of rear end gears should i look into and how hard is it to add a manual tranny?
with the right manual tranny, you could probably keep your stock rear gears
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Old 03-30-2013, 05:44 PM   #9
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How many miles do think you will REALISTICALLY drive it in a year? This is the big question? AND, of those miles, how many do you think you'll actually be driving in top gear where an overdrive might add to your fuel economy? A lot of owners think they are going to save a lot of money putting in an overdrive transmission, but, it all comes down to the number of HWY miles driven in a year.

In good tune and decent driving (start there first), many owners get about 18 mpg on the HWY (key word here) with an 81. Some have reported a little higher, some lower. So, let's say you spent a couple grand and a month of labor and installed a 200R with overdrive and you were able to improve your HWY mileage up to 22 mpg. [don't forget that most people installing an O/D tranny don't get the OD part just right and end up using a manual switch ...so it's not usually as 'seamless' as the regular tranny]. Anyway, doing this, you 'might' possibly get 23, but lets be realistic and use 22 as a starting number. Using these numbers here is what your savings would look like:

Savings per miles driven @ $3.65/gal:
3,000 miles per year = $111/yr savings
5,000 miles per year = $184/yr savings
8,000 miles per year = $295/yr savings
12,000 mile per year = $442/yr savings
20,000 mile per year = $737/yr savings

Achieving these savings would assume that all your mileage is HIGHWAY and you'd be able to use top gear almost all the time, which, for most people, it almost never is. So that means that these are OPTIMISTIC numbers. But it gives you a guide. If you didn't use overdrive that much, having the overdrive for periodic runs here and there wouldn't give you the yearly totals listed above but a percentage of those numbers.

I'm all for adding an overdrive, I'd like to add one to my 81, and I might in the future, or my 2nd gen Trans Am. But the savings above show you really need to drive a lot in top gear to justify the savings. I can drive mine in highway speeds a lot, but depends on the miles per year driven. In my Trans Am, which I drive a lot to work and see customers, I was suprised to find out I only put on about bare 3000 miles last year. I would have sworn I put on more than 5K. Almost all of that is hwy miles. But even at that, it's hard to for me to make an argument for an OD.

Now, if your tranny dies, of course your economic argument for an overdrive definitely tilts towards the OD. I guess in FL you might use yours all yr round and put on a lot more miles. More than anything, you want to make sure it is in the best tune as possible. 81's with the CCC and computer-controlled carb actually could get decent miles per gallon.

Last edited by Mark G; 03-30-2013 at 05:58 PM.
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Old 03-30-2013, 06:53 PM   #10
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To answer your original question what is a 'loaded' 81: I was looking at a list of 81 options just this morning believe it or not. By 81, most vettes were pretty loaded. Of the appx 40,000 vettes, about 36,000 had door locks, rear window defogger, aluminum wheels, cruise, Auto Trans and power antenna. 30,000 had glass roof panels. So, 'most' 81's were pretty well optioned out. About 20,000 had stereo cassette and the balance had an 8-track player. About 20k had RWL tires.

Rare options were like: 4spd, Gymkahana Susp w/ heavy dut shocks, two-tone paint, Radio w/CB, Stereo with NO tape player. The rarest option is Radio Delete, which isn't really an options most would want to have anyway.

What you 'might' want to get your hands on if you are going to keep your 81, is a GM CCC computer controlled carb book, which you can buy off ebay for about $5-$10. This is THE book on the subject that the GM technicians used in training to learn about the system and understand the principles. It explains all about the emissions components and how to keep them in tune, and debug a sytem then it needs it. The CCC allowed 81's to run longer with less maintenance than the regular carbureted cars before it. I drove an 81 Caprice for about 200k miles, and it would sit and idle flat all day long without loping or cought and spit like a carb does. It got great fuel economy too. The other book I would suggest is an original GM service manual because it has emission troubleshooting trees that will help out if you need to debug problems. You won't get that info in other manuals.

The computer controlled carb essentially utilizes a mixture control solonoid that pulses metering rods up and down 10x/second to maintain a proper air/fuel mixture under operating and environmental conditions. It's basically the same principle as a modern fuel injected cars with fuel injectors that pulses or modulates itself to meter fuel for the most efficient stiotiometric level (air/fuel level), but does it with a carb. The 81's had a little more bottom end power too, according to reports from the day. But the CCC was the first generation computerized system therefore it wasn't as standard as OBD1 that came afterwards. However, it WAS sort of a defacto standard in that GM led the way and produced millions of cars with the CCC system (Caprice's, camaros, trans ams, El Caminos, Monte Carlos and that body of cars, pickups ...all the way up to the mid 80's that used the same exact system Corvettes used in 81. Parts are diminishing but obviously still out there.

Actually, I find the CCC system fun and exciting to work on. It's very bullet proof because it melds perfected Rochester carburetor technology along with computerized sensor technology. If the computer, sensors, or mixture control solonoid fails, it won't leave you stranded. If you read up on it, you'll find that it's a lot better than a standard carb set-up and not difficult to understand. If you want to do your own debugging of the system, you need to be aware that the vast majority of the scanners out there monitor OBD II system, some, expensive ones will read OBD1 system. That's because the SAE came up with standards and California implemented that car companies had to meet so there weren't a dozen different systems out there. Actually, OBD1 was based on a GM system (a direct relative of your 81's ccc). Now, some older scanners will monitor CCC systems if you have the 'right' cartridge, but usually only back to 83 or 82 because in 82 GM made some refinements to the system which improved the speed and number of readings per second. Only a few scanners will read the 81 system, just because by the time the manufacturers realized the technology was here to say and caught up to it, GM was on the 82-83 system and it was maintained until the mid to late 80's. A GM Tech 1 scanner is one good example. There is free-ware out there that monitor the mid CCC systems down to 82 but nobody has written code to interfece with 81's that I know (and I just corrosponted with the author of TunerPro.net freeware and he said "not that he's aware of".) However, you can get all of the computer codes from grounding the pins on the ALDL connector and counting the number of Check Engine light blinks. You really don't need a scanner. I'm just telling you this so you don't go and buy a Harbor Freight scanner and try to figure out how you can scan your system.

One item I WOULD keep as a spare is an extra ignition module. They rarely fail but I've gone through a couple in my 81 caprice and an older pickup. But when they do, you usually get about 10 seconds of warning, then you're down to walking until replaced. Keep one in your glove box just in case.

81's are great cars. They were optioned out better and rode smoother than 70's vettes, and a larger fuel tank. And even though they had less HP than some 70's vettes, they were several hundred lbs lighter than late 70's cars and that's like adding a lot more HP. They look great too!

Last edited by Mark G; 03-30-2013 at 07:59 PM.
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Old 03-30-2013, 08:15 PM   #11
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Mark G your my new best friend. If i dont use as daily driver it will be used for the jacksonville club events and cross country driving. Plus you know i got to show her sweet body off each weekend.
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Old 03-30-2013, 10:02 PM   #12
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Hey no problem. Here are a couple things that happen to high-mile CCC cars that you may want to know about and consider if you find you aren't getting good fuel economy. These assume your engine itself is in good condition, good compression and all that:

1) Oxygen sensor - They eventually get weak and fail. They are cheap for 81's and it could be weak even if you don't have a code. This is the #1 Item to check if you get a check engine light (CEL). Not a bad idea to try another.
2) Carb issues - The carb throttle shaft hole on the carb bodies wear from use. This is where the throttle shaft enters the carb, right where your return spring is. On high mileage cars (like mine) if you grab the area where the spring attaches to the shaft and wiggle it up/down, and feel it move a noticable amt, then you have excess wear. This is real common. The result is a loss of engine vacuum and poor economy and bad fuel atomization in severe situations because it lets air in at this point. It would have been nice if a replaceable bushing were installed here at the factory, but it wasn't. However, a common professional rebuild would include milling the hole larger and inserting a bushing in this area. If you notice engine issues, this could be one of a few compounding issues.

The other carb issue is a distorted bowl. This occurs from tightening the screws too much. From what I've read, you can rebuild a bunch of times and can't overcome internal vacuum leaks in a carb w/o straightening the carb bowl. So, of course most people say the carb is junk and buy a high-maintenance and leaky Holly. When they probably overtightened the screws too much in the first place. They make tools to straighten the carb out ...a professional rebuild would do this for you. If your car is high mile, I would almost recommend buying a professionally rebuilt carb. Not one rebuilt by a guy around the corner, but one that re-anodizes the parts and makes all the corrections, then puts them on a flow bench.
3) Intake Vacuum - 81's were the first to use an aluminum intake. It was a weight saving measure. But AL and cast iron have different expansion rates. The gasketing material they used back then wasn't as good. Over time, these gaskets develop leaks. This could be an intake leak that may result in low vacuum.
4) Distributor wear - 81 distributors had computer controlled advance and use an ignition module inside the distributor. But on higher mile cars, slop develops and affects timing slightly.
5) Sensors - They don't usually fail, but they can. Most of the electrical issues are related to poor connections. I remember a GM master technician giving me free advice at a parts counter on a issues I had with my 81 Caprice ..back in the late 80's. W/O even looking at the car, he knew I had a bad connection at one particular grey connector ...blah blah blah he told me where to look. I did and didn't see the corrosion he swore I would see. Well, I asked him about it and he walked right out to my car and in one motion, he reached down by the engine, unsnapped a particular connector and showed me the corrosion I didn't see. Yep, it was there. I cleaned it off, problem went away. He'd been through it a bunch of times he said. Saved me a bunch of time.
6) Computer Connection - The early computer connector was prone to faulty connections. I had a buddy that was a GM master tech back in the day (this is a different tech) and he was helping me with my 81 one time. I thought my computer was flakey, but he told me he guaranteed it wasn't my computer but a connection. I doubted him, in a chuckling sort of way. He dug out my computer, hooked up his Tech 1 and proceeded to wiggle a particular wire and said something like: "see the change on the scanner when I move the wire? You owe me a beer." So, if you ever run into an issue you THINK is a computer issue, inspect and straighten pins on the connector. He said he's seen dozens of cars that had those problems and it was common on those year. GM made a change to the connector he told me that pretty much resolved the problem.
7) Plug wires - Well, I'm sure you know they have a lifespan. I've changed wires before on other vehicles that were way overdue and was amazed I could feel the diffence.
8) Steering Box - If your car has over 50k miles, you might tighten up the steering a lot just by adjusting the steering box. There are two adjustments: One is the lower end-play (pre-load), the other is the pre-load of the ball/nut assembly. Most people adjust the top screw of the ball/nut assembly because they can do it easily on the car, but that's only 1/2 of the adjustment. The correct (and better) way of adjusting is to remove the steering box and remove the lower cover and tighten the lower nut first (not accessable mounted on the car). THEN, afterwards, adjust the ball/nut assembly. If you have the time, this is a cheap performance upgrade that won't cost you a dime and could really make the car feel like it should. If it's 80-100+k miles, consider a rebuild, or replacement, or Borgleson steering box conversion. My steering box had worn bushings at the output shaft so no amount of adjustment would have fixed that. I rebuilt it, she's good. I read a Corvette magazine back in the early 80's and this was one of the best field repairs an owner could do that didn't cost anything but a little labor. It was listed above new performance shocks, bushings and all that.
9) Rear Wheel Bearings - I haven't changed mine yet, but I probably need to. Most C3 owners say they are good for 80-100k miles ...with 100K being on borrowed time. It's a weak point to be considered for cars with high miles prior to any long cross-country journey. When they fail, the warning can be extremely short (as little as seconds) before seizing up or snapping. Usually there is a growling noise that alerts you to a problem.

I'm not implying that your car has any of the above situations, but that they 'can' exist on some cars and manifest as poor economy and engine stumble, etc. There are probably other problems I forgot or don't know about that hopefully others will list.

Last edited by Mark G; 03-30-2013 at 10:13 PM.
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Old 03-31-2013, 03:38 AM   #13
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The vette has only 57k miles so all you doing is giving me a heads up on wonderful weekends with my baby. All the tips are every useful for someone new to the true late model vettes.
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