Just got my first Corvette and I already need help
09-09-2001, 11:46 AM
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Just got my first Corvette and I already need help
Say Hi to the new ugly guy. I just purchased a 71 LS-5 454 Sport Coupe. It's my first Corvette, and I'm already in need of help! There's a knock or rapping sounds coming from the engine that I haven't been able to locate. More on that later, first I'll give a description of the car (mainly cuz I love talking about it).
It's brands hatch green with saddle vinyl interior, auto with air conditioning. VIN 194371S115910. It came with no documentation at all; all I know is it came from Arkansas. I'm in Georgia.
It's absolutely beautiful! It gets compliments from everybody. I wasn't intending to get a coupe or spend this much (please don't ask) but I fell in love with it from the first picture I saw. I found myself thinking about it all the time, like I was a teenager in love, so I figured I had to get it or I would never be able to sleep.
Here are some pics:
http://members.home.net/fristoe1/71/71corvette.jpg
http://members.home.net/fristoe1/71/71green1.jpg
http://members.home.net/fristoe1/71/71greene.jpg
http://members.home.net/fristoe1/71/71greeni.jpg
http://members.home.net/fristoe1/71/71vetteside.jpg
It has been recently repainted (they painted over the trim plate on the door jamb) but the plate indicates that the colors are original.
The engine block appears to be the original, with the correct VIN derivative and LS-5 engine code stamped on it. The engine appears to have been rebuilt or at least refurbished recently; it is clean and has a fresh coat of orange paint and it appears to be sludge-free, at least from looking under the valve covers. The parts of the engine that are obviously not original are an Edelbrock Q-jet (#1901) carb, a Mallory electronic distributor, Bosch coil, Hooker headers (which are showing small rust spots), and Crane 1.72 steel roller rockers. It may have an aftermarket cam because the idle is a little lopey. The motor ran up fine, but with stock 3.08 gears it isn't a race car.. runs more smooth than quick, and leaves no rubber. I think the carb could use a lot of adjusting, for one thing, it won't hold a fast idle, so it's hard to keep running when started cold. I always have to start it at least twice.
It has a brand new exhaust. It has new Goodyear Eagle #1 raised gold letter shoes, and the rally wheel trim looks brand new. The steering needs refreshing; it's a little loose, the wheel is off center, and it pulls slightly to one side.
The interior looks great, except for the seat belts. The interior has a lot of replacement trim items, because a lot of it looks new. I understand why the seat belts hadn't been replaced when I checked on the prices ($500 - $600 ouch). The carpet is a bit worn. The seats are good. It has a cheap aftermarket Pioneer CORVETTE AM/FM cassette units that's wired so it loses its memory when the car is shut off. All the gauges work, but I guess the clock and trip counter gears are stripped, because they cannot be reset. The wipers, lights, and fiber optics all work. The air conditioning works. Does this car maybe sound familiar to anyone? Eventually I'd like to try to trace its history.
Anyway (thanks for keeping with me!) Here's the first problem. I drove it daily for about a week, and then once (luckily it was sitting in my driveway) when trying to start it, I got a puff of smoke from the ignition key cylinder area (that still baffles me) and from the key buzzer/horn relay area under the hood. Then it was completely dead; the only thing that worked was the horn. After days of scratching my head, I hooked a jumper from the battery to the coil, and another from the battery to the starter, and it started right up (much better than it normally did!) and I drove it into the garage. I then replaced the horn relay, two fusible links at the horn relay, a fusible link that had fried at the starter, and the ignition switch. Somehow during my troubleshooting I stripped the plastic gear that mates to the lock cylinder. I replaced the cylinder, but despite trying to get the ignition switch and the lock cylinder in the same position when I installed it, I think I'm going to have to go farther in and replace that gear because I still have to turn it to ACC to shut the car off. After I did all this, the car started and ran as before. I did notice another wisp of smoke coming from under the dash next to the steering column sometime after the fix, so I think it's gonna need fixing again. Maybe the starter is pulling too much current for the 30-year-old wiring.
Now here's my current problem! I ran it around the neighborhood a couple of times, pulled it into the driveway, and sat in neutral while I ran the engine up to about 4500 rpm. as I let off the gas, a loud knock started in the engine. It's a rapping, almost a banging. Nothing else seems amiss; the water temp is ok, the oil pressure ok, the fan isn't hitting anything, it seems so run normally except for this knock! It's there at idle, and at higher rpms. It sounds like its coming from everywhere in the engine block. So far, the only thing I've done is take the valve covers off to look, and nothing appears broken in there. I'm heartbroken, I hope I haven't ruined the engine. I just got it! It doesn't even have plates yet. And now it's just sitting in the garage looking beautiful. My next steps are to remove all the accessory belts and run it to see if the knock is still there, and then I was going to ground one plug wire at a time to see if the knock is coming from a particular cylinder.
I have the service manual, assembly manual, Haynes and Chilton's manuals. I don't have a lot of resources, just the basic tools. I don't have experience with doing major repairs myself (nothing beyond changing starters, exhausts, water pumps, and the like), nor do I know anyone who does.
Please, does anyone have any ideas on what could have broken on running *down* the rpms? Can anyone offer any hope? Or am I looking at an overhaul or replacement engine? What are some other things I could check? Thanks for hanging with me this long.
[Modified by 71 BHG 454, 3:51 PM 9/9/2001]
It's brands hatch green with saddle vinyl interior, auto with air conditioning. VIN 194371S115910. It came with no documentation at all; all I know is it came from Arkansas. I'm in Georgia.
It's absolutely beautiful! It gets compliments from everybody. I wasn't intending to get a coupe or spend this much (please don't ask) but I fell in love with it from the first picture I saw. I found myself thinking about it all the time, like I was a teenager in love, so I figured I had to get it or I would never be able to sleep.
Here are some pics:
http://members.home.net/fristoe1/71/71corvette.jpg
http://members.home.net/fristoe1/71/71green1.jpg
http://members.home.net/fristoe1/71/71greene.jpg
http://members.home.net/fristoe1/71/71greeni.jpg
http://members.home.net/fristoe1/71/71vetteside.jpg
It has been recently repainted (they painted over the trim plate on the door jamb) but the plate indicates that the colors are original.
The engine block appears to be the original, with the correct VIN derivative and LS-5 engine code stamped on it. The engine appears to have been rebuilt or at least refurbished recently; it is clean and has a fresh coat of orange paint and it appears to be sludge-free, at least from looking under the valve covers. The parts of the engine that are obviously not original are an Edelbrock Q-jet (#1901) carb, a Mallory electronic distributor, Bosch coil, Hooker headers (which are showing small rust spots), and Crane 1.72 steel roller rockers. It may have an aftermarket cam because the idle is a little lopey. The motor ran up fine, but with stock 3.08 gears it isn't a race car.. runs more smooth than quick, and leaves no rubber. I think the carb could use a lot of adjusting, for one thing, it won't hold a fast idle, so it's hard to keep running when started cold. I always have to start it at least twice.
It has a brand new exhaust. It has new Goodyear Eagle #1 raised gold letter shoes, and the rally wheel trim looks brand new. The steering needs refreshing; it's a little loose, the wheel is off center, and it pulls slightly to one side.
The interior looks great, except for the seat belts. The interior has a lot of replacement trim items, because a lot of it looks new. I understand why the seat belts hadn't been replaced when I checked on the prices ($500 - $600 ouch). The carpet is a bit worn. The seats are good. It has a cheap aftermarket Pioneer CORVETTE AM/FM cassette units that's wired so it loses its memory when the car is shut off. All the gauges work, but I guess the clock and trip counter gears are stripped, because they cannot be reset. The wipers, lights, and fiber optics all work. The air conditioning works. Does this car maybe sound familiar to anyone? Eventually I'd like to try to trace its history.
Anyway (thanks for keeping with me!) Here's the first problem. I drove it daily for about a week, and then once (luckily it was sitting in my driveway) when trying to start it, I got a puff of smoke from the ignition key cylinder area (that still baffles me) and from the key buzzer/horn relay area under the hood. Then it was completely dead; the only thing that worked was the horn. After days of scratching my head, I hooked a jumper from the battery to the coil, and another from the battery to the starter, and it started right up (much better than it normally did!) and I drove it into the garage. I then replaced the horn relay, two fusible links at the horn relay, a fusible link that had fried at the starter, and the ignition switch. Somehow during my troubleshooting I stripped the plastic gear that mates to the lock cylinder. I replaced the cylinder, but despite trying to get the ignition switch and the lock cylinder in the same position when I installed it, I think I'm going to have to go farther in and replace that gear because I still have to turn it to ACC to shut the car off. After I did all this, the car started and ran as before. I did notice another wisp of smoke coming from under the dash next to the steering column sometime after the fix, so I think it's gonna need fixing again. Maybe the starter is pulling too much current for the 30-year-old wiring.
Now here's my current problem! I ran it around the neighborhood a couple of times, pulled it into the driveway, and sat in neutral while I ran the engine up to about 4500 rpm. as I let off the gas, a loud knock started in the engine. It's a rapping, almost a banging. Nothing else seems amiss; the water temp is ok, the oil pressure ok, the fan isn't hitting anything, it seems so run normally except for this knock! It's there at idle, and at higher rpms. It sounds like its coming from everywhere in the engine block. So far, the only thing I've done is take the valve covers off to look, and nothing appears broken in there. I'm heartbroken, I hope I haven't ruined the engine. I just got it! It doesn't even have plates yet. And now it's just sitting in the garage looking beautiful. My next steps are to remove all the accessory belts and run it to see if the knock is still there, and then I was going to ground one plug wire at a time to see if the knock is coming from a particular cylinder.
I have the service manual, assembly manual, Haynes and Chilton's manuals. I don't have a lot of resources, just the basic tools. I don't have experience with doing major repairs myself (nothing beyond changing starters, exhausts, water pumps, and the like), nor do I know anyone who does.
Please, does anyone have any ideas on what could have broken on running *down* the rpms? Can anyone offer any hope? Or am I looking at an overhaul or replacement engine? What are some other things I could check? Thanks for hanging with me this long.
[Modified by 71 BHG 454, 3:51 PM 9/9/2001]
09-09-2001, 12:18 PM
#2
Le Mans Master
Re: Just got my first Corvette and I already need help (71 BHG 454)
Now here's my current problem! I ran it around the neighborhood a couple of times, pulled it into the driveway, and sat in neutral while I ran the engine up to about 4500 rpm. as I let off the gas, a loud knock started in the engine. It's a rapping, almost a banging.
If this noise is happening even at idle, and the oil pressure is really low I would suspect that your engine probably spun a bearing. :cry :cry
Kevin
09-09-2001, 12:31 PM
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Re: Just got my first Corvette and I already need help (Kevin_73)
The knock is there even at idle, and at higher rpms. I did check the the oil pressure after this happened and it was hanging right around 35psi at idle. I haven't run it up past about 2500 rpm since this happened, and I haven't driven it at all except to pull forward about 20 feet into the garage.
09-09-2001, 12:41 PM
#4
Burning Brakes
Re: Just got my first Corvette and I already need help (71 BHG 454)
I was once driving down the street only doing 20mph when all the sudden this terrible knocking sound started from the engine, I thought the worst. Turns out the bearing in the water pump just gave up but the knocking it made was unbelievable. I would start with an automotive stethoscope [there fairly cheap at the local parts shop] and go around the engine and try to narrow it down.
09-09-2001, 12:43 PM
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Re: Just got my first Corvette and I already need help (71 BHG 454)
i dont know whats wrong, but you shouldnt be revving it at all, if you suspect a serious problem. think about it, the engine turns about 1000rpms when pulling it into the garage, and it takes you about 2 mins to start it, pull it i and shut it off, in that time the engine turned over 2000 times, so if you suspect a problem its making it worse by revving it or driving it.
only thing i can suggest it to change the oil and take a good look at the old stuff, to see if there's metal peices in it.
[Modified by xfactor974, 4:45 PM 9/9/2001]
only thing i can suggest it to change the oil and take a good look at the old stuff, to see if there's metal peices in it.
[Modified by xfactor974, 4:45 PM 9/9/2001]
09-09-2001, 01:13 PM
#6
Le Mans Master
Re: Just got my first Corvette and I already need help (xfactor974)
I had a loud knocking in one of my GM engines and it turned out to be that the torque converter bolts were loose on the flywheel. I hope for your sake that it is something as simple as that. You got a real nice car, and whatever the noise is, it can be fixed. Let us know what you find. Look at the area where the steering colum bolts to the dash and look for pinched wires in that area, a lot of times that horse shoe shaped bracket pinches the harness or chaffes the wiring harness if it is not routed correctly.Roger
09-09-2001, 01:25 PM
#7
Le Mans Master
Re: Just got my first Corvette and I already need help (Roger L. Gibbons)
I forgot to mention if you opened one of the fusible links at the starter, there is a lot of current going through that circuit. There is a potential for a fire or serious harness damage especially if you are seeing smoke. One of the links powers your instrument panel and ignition circuit. Roger
09-09-2001, 01:41 PM
#8
Team Owner
Re: Just got my first Corvette and I already need help (Roger L. Gibbons)
Grab the front of your water pump and see if it is loose. I had a 350 that had a knocking noise and when I replaced the water pump it went away some. It turned out that I had spun a bearing but my water pump bearing was shot also and when I replaced it the knock got alot quieter. I hope you didn't spin a bearing being the original engine and all. Please be careful when trying to diagnose this problem because if you thow a rod through your block it will make a nice boat anchor.
Good luck and my fingers are crossed that you don't have to go through what I did. Mine tured out good but expensive as I installed a ZZ4 and now it runs GREAT.
John
P.S. Welcome to the Forum :seeya :seeya :seeya
[Modified by theandies, 11:43 AM 9/9/2001]
Good luck and my fingers are crossed that you don't have to go through what I did. Mine tured out good but expensive as I installed a ZZ4 and now it runs GREAT.
John
P.S. Welcome to the Forum :seeya :seeya :seeya
[Modified by theandies, 11:43 AM 9/9/2001]
09-09-2001, 02:23 PM
#9
Melting Slicks
Re: Just got my first Corvette and I already need help (71 BHG 454)
Great looking car :cool: Sorry to hear about your troubles but maybe this will help. I only had 4800 miles on my engine when it started knocking so I know how you must feel :cry I took the valve covers off and checked all of the rocker arms hoping that maybe it was only a loose rocker ! As I checked the the rockers I noticed that one of valves had some play side to side, up and down so thats no good. :cry I took the head off and took it to a machine shop and was told that the valve guide looked like it had 100,000 miles run on them :eek: So I replaced the heads :D Good Luck :cheers:
[Modified by Intimidator454, 1:24 PM 9/9/2001]
[Modified by Intimidator454, 1:25 PM 9/9/2001]
[Modified by Intimidator454, 1:24 PM 9/9/2001]
[Modified by Intimidator454, 1:25 PM 9/9/2001]
09-09-2001, 02:53 PM
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Re: Just got my first Corvette and I already need help (71 BHG 454)
hi new ugly guy.welcome :seeya
that is a beautiful vette you got there.hopefully the problem is not to big.
everybody here had his/her share of misfortunes with the corvette.
but there is always someone here who went through the same problem
and they are always willing to help.
good luck
that is a beautiful vette you got there.hopefully the problem is not to big.
everybody here had his/her share of misfortunes with the corvette.
but there is always someone here who went through the same problem
and they are always willing to help.
good luck
09-09-2001, 07:18 PM
#11
Le Mans Master
Re: Just got my first Corvette and I already need help (71 BHG 454)
WElcome to the forum. Nice Vette! 
If you haven't already, get a battery disconnect switch and USE it. I'm of no use when it comes to electrical demons other than to say it sounds like you let the majic smoke escape. :lol: Good Luck with the car and keep posting. If you make more posts about single topics those with experience in those areas might see your posts and help you faster than if it gets buried in a long post. At any rate there have probably been 20 people who just went through the same thing you went through so ask away! BTW, you can get your seatbelts rewebbed. SsnakeOyl does that. The archives will probably have their contact info. ~Juliet
If you haven't already, get a battery disconnect switch and USE it. I'm of no use when it comes to electrical demons other than to say it sounds like you let the majic smoke escape. :lol: Good Luck with the car and keep posting. If you make more posts about single topics those with experience in those areas might see your posts and help you faster than if it gets buried in a long post. At any rate there have probably been 20 people who just went through the same thing you went through so ask away!
BTW, you can get your seatbelts rewebbed. SsnakeOyl does that. The archives will probably have their contact info. ~Juliet
09-09-2001, 08:41 PM
#12
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Re: Just got my first Corvette and I already need help (Juliet)
Thanks to all for the suggestions! Sorry for the long post, I guess It was a bit of venting, too. In the future I'll separate out my topics.
I'm hoping this is the water pump. It seems the quickest way to eliminate that is to remove all the belts and fire it up briefly to see if the knock is still there with the pump not running. I do have a mechanics stethescope but my experience with using them is that it takes a while to find a sound that is resonating throughout the block. I haven't had the time to get back in there and troubleshoot any farther yet. Draining the oil and inspecting it first is a great idea, and I'll do that first.
Unfortunately, I didn't have the option of leaving it in the driveway or pushing it in the garage, I had to run it.
The quick disconnect switch is a great idea. I'd like to find one that mounts at the battery. Mine uses side mount connections, don't know if that is stock. My starter must be pulling more current than it's supposed to. If I don't go up in flames first, I'll be looking at that when I nail this knocking problem.
Thanks again y'all for the help
I'm hoping this is the water pump. It seems the quickest way to eliminate that is to remove all the belts and fire it up briefly to see if the knock is still there with the pump not running. I do have a mechanics stethescope but my experience with using them is that it takes a while to find a sound that is resonating throughout the block. I haven't had the time to get back in there and troubleshoot any farther yet. Draining the oil and inspecting it first is a great idea, and I'll do that first.
Unfortunately, I didn't have the option of leaving it in the driveway or pushing it in the garage, I had to run it.
The quick disconnect switch is a great idea. I'd like to find one that mounts at the battery. Mine uses side mount connections, don't know if that is stock. My starter must be pulling more current than it's supposed to. If I don't go up in flames first, I'll be looking at that when I nail this knocking problem.
Thanks again y'all for the help
09-09-2001, 09:15 PM
#13
Le Mans Master
Re: Just got my first Corvette and I already need help (71 BHG 454)
Welcome, after you check out the H2O pump (remove belts and run it for few seconds and you will know if it is pump), if not, pull pan with engine in car, may have to jack up motor little and check rods for looseness, you will be able to tell if they are. You also can remove one main cap at at time to check for spun bearing. BE Sure to RETORQUE them. Good luck, anyone out there near who can help the new guy? :seeya
:seeya
09-09-2001, 09:23 PM
#14
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Re: Just got my first Corvette and I already need help (LT1driver)
Beautiful car - can't offer any sugestions beyond what's already been said, but best of luck and keep us posted on what you find.
09-09-2001, 10:11 PM
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St. Jude Donor '03-'10
Re: Just got my first Corvette and I already need help (71 BHG 454)
welcome! and that definitely is a great looking vette! :cool:
09-09-2001, 10:24 PM
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St. Jude Donor '07
Re: Just got my first Corvette and I already need help (Chris Fowler '80)
I could be a header leak too. That usually sounds like a knock. Welcome and car looks great.
Budman
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09-09-2001, 10:45 PM
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Re: Just got my first Corvette and I already need help (71 BHG 454)
Again, great looking car!!
I panicked when my car started to rap, turned out to be a loose crank pulley.
I panicked when my car started to rap, turned out to be a loose crank pulley.
09-09-2001, 10:56 PM
#18
Safety Car
Re: Just got my first Corvette and I already need help (71 BHG 454)
Hello fellow 71, 454 owner. Your vin indicates your car was made in the later of the 71 production year, mine was earlier 194371S109177. Glad to have you aboard, beautiful car. Take Juliets advice, disconnect battery when not in use, whether you see smoke or not. Hope you find the noise, good time to get a stethiscope. :yesnod:
Hope you find the noise, good time to get a stethiscope. :yesnod:
09-10-2001, 10:57 AM
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Melting Slicks
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Re: Just got my first Corvette and I already need help (2nspire)
This advice was given to me, and I'm passing it on: Buy a fire extinguisher and keep it in the car at all times. That's a beautiful car you have there, and I wouldn't want to see it become a burned out shell on a trailer next year at Carlisle. Especially with the electrical problems you're having.
Smoke is never a good thing. That means parts are getting much hotter than designed. Which means your resistance is screwed up somewhere in the circuit, and you are probably drawing too much current through that resistance. Maybe Bubba used a smaller wire guage somewhere? :smash:
Good luck with the electronics! These cars can acquire some mysterious electrical gremlins. Sometimes you just need to grab a beer :cheers: and get a preist to exorcise your car :yesnod:
Lastly, welcome to the forum. This is a great bunch of people who contribute to make this place an invaluable resource :cool:
Smoke is never a good thing. That means parts are getting much hotter than designed. Which means your resistance is screwed up somewhere in the circuit, and you are probably drawing too much current through that resistance. Maybe Bubba used a smaller wire guage somewhere? :smash:
Good luck with the electronics! These cars can acquire some mysterious electrical gremlins. Sometimes you just need to grab a beer :cheers: and get a preist to exorcise your car :yesnod:
Lastly, welcome to the forum. This is a great bunch of people who contribute to make this place an invaluable resource :cool: