I Need Serious Help ASAP
, dont know what to tell you man. Post a vid maybe someone can ID the sound. 
03-25-2010, 05:42 PM
#52
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
03-26-2010, 03:50 PM
#53
Supreme Member
iTrader: (5)
Join Date: Aug 2006
Location: Cleveland, Ohio
Posts: 2,491
Likes: 0
Received 5 Likes
on
5 Posts
Car: 89' IROC-Z
Engine: LO3
Transmission: 700R4
Axle/Gears: 10-Bolt/2.73
Re: I Need Serious Help ASAP
What is your oil pressure reading? Could have enough oil but the wrong weight. Have you done an oil change recently?
03-26-2010, 06:45 PM
#54
Member
Join Date: Aug 2009
Location: AZ
Posts: 332
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1978 Chevrolet impala
Engine: 350ci 300hp/356tq pace crate
Transmission: 700r4
Axle/Gears: 3.42 Yukon posi
Re: I Need Serious Help ASAP
Easy way to ident the 400 SBC is the steam holes in the cylinder heads.
Also, don't worry bud, I feel your pain when it comes to clunky mystery cars, and just like you I tend to pounce on a deal before i drive it, and get stuck with a highly questionable machine that needs lots of work.
That being said, I know I'm not alone when I say I'd give a kidney for that 400 (if that's what it is). Just be patient, know that it will probably nickle and dime you for a fair amount, and keep in mind that the PO didn't sell you his heavily customized 'bird with a giant motor because he did his homework and it ran like a racehorse.
He screwed it up. From the sounds of it, he screwed it up pretty darn good. Now it's up to you to clean up after him and turn it into a sturdy asphalt eating machine!
The only car you can't fix is the one you sell. If worst comes to very worst, you can always pick up a cheapo DD while you save up for an overhaul.
Above all remember: You have a firebird with a 400 in it. That's not something you see every day. You also have an appropriately sized carb on top of a good manifold with a decent cam. 3/4 of the battle has been won for ya, now you just gotta deal with the politics of what all the PO screwed up putting that big fat block in there.
-----
What KIND of burning smell? Oil? Wires? did it smell like burnt oranges? Look for spatter in your engine bay or places where oil or other fluids might be leaking on your exhaust. Check your tranny fluid level. Be aware that with the funky way you say it's been operating, your transmission may very well be slow-roasting itself to a delicious golden-brown. That's a pretty big motor to stick in front of a shady GM tranny, auto OR stick. ALSO be aware that in some cases backfiring thru a Holley may mean it needs a rebuild. Blown power valves ftl.
Also, don't worry bud, I feel your pain when it comes to clunky mystery cars, and just like you I tend to pounce on a deal before i drive it, and get stuck with a highly questionable machine that needs lots of work.
That being said, I know I'm not alone when I say I'd give a kidney for that 400 (if that's what it is). Just be patient, know that it will probably nickle and dime you for a fair amount, and keep in mind that the PO didn't sell you his heavily customized 'bird with a giant motor because he did his homework and it ran like a racehorse.
He screwed it up. From the sounds of it, he screwed it up pretty darn good. Now it's up to you to clean up after him and turn it into a sturdy asphalt eating machine!
The only car you can't fix is the one you sell. If worst comes to very worst, you can always pick up a cheapo DD while you save up for an overhaul.
Above all remember: You have a firebird with a 400 in it. That's not something you see every day. You also have an appropriately sized carb on top of a good manifold with a decent cam. 3/4 of the battle has been won for ya, now you just gotta deal with the politics of what all the PO screwed up putting that big fat block in there.
-----
What KIND of burning smell? Oil? Wires? did it smell like burnt oranges? Look for spatter in your engine bay or places where oil or other fluids might be leaking on your exhaust. Check your tranny fluid level. Be aware that with the funky way you say it's been operating, your transmission may very well be slow-roasting itself to a delicious golden-brown. That's a pretty big motor to stick in front of a shady GM tranny, auto OR stick. ALSO be aware that in some cases backfiring thru a Holley may mean it needs a rebuild. Blown power valves ftl.
Last edited by Grumbles; 03-26-2010 at 06:54 PM.
03-26-2010, 07:05 PM
#55
Member
Join Date: Aug 2009
Location: AZ
Posts: 332
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1978 Chevrolet impala
Engine: 350ci 300hp/356tq pace crate
Transmission: 700r4
Axle/Gears: 3.42 Yukon posi
Re: I Need Serious Help ASAP
I'd also definitely have the valve covers off for a peak at your valve train. Sludge hangin' out with your rockers could be a good clue as to what shape the motor's in.
03-26-2010, 08:53 PM
#56
Re: I Need Serious Help ASAP
I don't believe you've mentioned anything about your sparkplugs yet.
Are they fouling? What is your manifold vacuum reading like?
Have you done a compression check on all the cylinders?
Where are the sounds coming from?
An engine can get noisy due to lack of oil pressure, dilution of the oil by fuel or coolant, or because of a mechanical problem. All of these possibilities are serious, so you need to determine the source ASAP.
Engine noises also commonly end up being a failing accessory like a waterpump, power-steering pump, or alternator.
Free-revving when in gear can be from a slipping transmission or a failing torque converter. I don't know exactly what symptom you're experiencing from your description so far. Best bet is to have an experienced mechanic check it out ASAP.
FYI, your initial timing will be fine at anything between 5* and 15* BTDC.
Typical vacuum advance will add between 10* and 15* to this number at idle when full manifold vacuum is applied to the distributor.
At idle, and advance of between 25* and 30* (combined initial + vacuum) is fine.
The centrifugal advance should add in another 15* to 20* of advance to give you 30* to 35* total at WOT (initial + centrifugal). Vacuum advance shouldn't be applied at WOT.
I'm pretty sure most modern replacement waterpumps have sealed bearings, so running straight water in the summer should not cause any problems as long as your cooling system is holding pressure. A leak will reduce pressure (more than you think) and allow the coolant to boil, which will puke fluid and also cause you to run hot. Have you checked the operation of your waterpump?
With the tstat removed, you should be able to look down into your radiator through the cap hole and watch the water flowing through quickly. If not, it is possible that the pump is bad, or the wrong pump was used, for instance a reverse rotation pump used in a clockwise rotation application.
Sometimes it helps to eliminate possible sources of vacuum leaks for troubleshooting purposes. I like to plug off sources for the power brakes, the PCV system, and any other vacuum supply to narrow down possibilities.
Keep in mind that wire connections can look good, but still be bad causing intermittent misfires, charging problems, or dying. On a 3rdgen, the fusable link wires going down to the starter are about the poorest quality of wire you will ever see. The strands break internally under the insulation so you never see it. Some people will let the starter hang from the wires when removing it, and that often breaks the wire strands. Fusable links themselves can go bad from heat damage and/or corrosion. Battery cables can corrode under the insulation as well as be damaged by exhaust heat.
For troubleshooting I like to use heavy gauge jumper cables to connect the negative on the battery straight to the engine block. If this cures the starting problem, then you had a weak ground, like the grounding strap mentioned. If you're careful you can also hook the jumper from the battery positive to the post on the starter to test the positive cable.
You can test charging voltage with a $5 DVOM.
As mentioned backfiring often blows out the power valves on Holley type carburetors, and that can cause fueling problems, namely an excessively rich condition that can foul the plugs.
Are they fouling? What is your manifold vacuum reading like?
Have you done a compression check on all the cylinders?
Where are the sounds coming from?
An engine can get noisy due to lack of oil pressure, dilution of the oil by fuel or coolant, or because of a mechanical problem. All of these possibilities are serious, so you need to determine the source ASAP.
Engine noises also commonly end up being a failing accessory like a waterpump, power-steering pump, or alternator.
Free-revving when in gear can be from a slipping transmission or a failing torque converter. I don't know exactly what symptom you're experiencing from your description so far. Best bet is to have an experienced mechanic check it out ASAP.
FYI, your initial timing will be fine at anything between 5* and 15* BTDC.
Typical vacuum advance will add between 10* and 15* to this number at idle when full manifold vacuum is applied to the distributor.
At idle, and advance of between 25* and 30* (combined initial + vacuum) is fine.
The centrifugal advance should add in another 15* to 20* of advance to give you 30* to 35* total at WOT (initial + centrifugal). Vacuum advance shouldn't be applied at WOT.
I'm pretty sure most modern replacement waterpumps have sealed bearings, so running straight water in the summer should not cause any problems as long as your cooling system is holding pressure. A leak will reduce pressure (more than you think) and allow the coolant to boil, which will puke fluid and also cause you to run hot. Have you checked the operation of your waterpump?
With the tstat removed, you should be able to look down into your radiator through the cap hole and watch the water flowing through quickly. If not, it is possible that the pump is bad, or the wrong pump was used, for instance a reverse rotation pump used in a clockwise rotation application.
Sometimes it helps to eliminate possible sources of vacuum leaks for troubleshooting purposes. I like to plug off sources for the power brakes, the PCV system, and any other vacuum supply to narrow down possibilities.
Keep in mind that wire connections can look good, but still be bad causing intermittent misfires, charging problems, or dying. On a 3rdgen, the fusable link wires going down to the starter are about the poorest quality of wire you will ever see. The strands break internally under the insulation so you never see it. Some people will let the starter hang from the wires when removing it, and that often breaks the wire strands. Fusable links themselves can go bad from heat damage and/or corrosion. Battery cables can corrode under the insulation as well as be damaged by exhaust heat.
For troubleshooting I like to use heavy gauge jumper cables to connect the negative on the battery straight to the engine block. If this cures the starting problem, then you had a weak ground, like the grounding strap mentioned. If you're careful you can also hook the jumper from the battery positive to the post on the starter to test the positive cable.
You can test charging voltage with a $5 DVOM.
As mentioned backfiring often blows out the power valves on Holley type carburetors, and that can cause fueling problems, namely an excessively rich condition that can foul the plugs.
03-27-2010, 10:48 AM
#57
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
Easy way to ident the 400 SBC is the steam holes in the cylinder heads.
Also, don't worry bud, I feel your pain when it comes to clunky mystery cars, and just like you I tend to pounce on a deal before i drive it, and get stuck with a highly questionable machine that needs lots of work.
That being said, I know I'm not alone when I say I'd give a kidney for that 400 (if that's what it is). Just be patient, know that it will probably nickle and dime you for a fair amount, and keep in mind that the PO didn't sell you his heavily customized 'bird with a giant motor because he did his homework and it ran like a racehorse.
He screwed it up. From the sounds of it, he screwed it up pretty darn good. Now it's up to you to clean up after him and turn it into a sturdy asphalt eating machine!
The only car you can't fix is the one you sell. If worst comes to very worst, you can always pick up a cheapo DD while you save up for an overhaul.
Above all remember: You have a firebird with a 400 in it. That's not something you see every day. You also have an appropriately sized carb on top of a good manifold with a decent cam. 3/4 of the battle has been won for ya, now you just gotta deal with the politics of what all the PO screwed up putting that big fat block in there.
-----
What KIND of burning smell? Oil? Wires? did it smell like burnt oranges? Look for spatter in your engine bay or places where oil or other fluids might be leaking on your exhaust. Check your tranny fluid level. Be aware that with the funky way you say it's been operating, your transmission may very well be slow-roasting itself to a delicious golden-brown. That's a pretty big motor to stick in front of a shady GM tranny, auto OR stick. ALSO be aware that in some cases backfiring thru a Holley may mean it needs a rebuild. Blown power valves ftl.
Also, don't worry bud, I feel your pain when it comes to clunky mystery cars, and just like you I tend to pounce on a deal before i drive it, and get stuck with a highly questionable machine that needs lots of work.
That being said, I know I'm not alone when I say I'd give a kidney for that 400 (if that's what it is). Just be patient, know that it will probably nickle and dime you for a fair amount, and keep in mind that the PO didn't sell you his heavily customized 'bird with a giant motor because he did his homework and it ran like a racehorse.
He screwed it up. From the sounds of it, he screwed it up pretty darn good. Now it's up to you to clean up after him and turn it into a sturdy asphalt eating machine!
The only car you can't fix is the one you sell. If worst comes to very worst, you can always pick up a cheapo DD while you save up for an overhaul.
Above all remember: You have a firebird with a 400 in it. That's not something you see every day. You also have an appropriately sized carb on top of a good manifold with a decent cam. 3/4 of the battle has been won for ya, now you just gotta deal with the politics of what all the PO screwed up putting that big fat block in there.
-----
What KIND of burning smell? Oil? Wires? did it smell like burnt oranges? Look for spatter in your engine bay or places where oil or other fluids might be leaking on your exhaust. Check your tranny fluid level. Be aware that with the funky way you say it's been operating, your transmission may very well be slow-roasting itself to a delicious golden-brown. That's a pretty big motor to stick in front of a shady GM tranny, auto OR stick. ALSO be aware that in some cases backfiring thru a Holley may mean it needs a rebuild. Blown power valves ftl.
I don't believe you've mentioned anything about your sparkplugs yet.
Are they fouling? What is your manifold vacuum reading like?
Have you done a compression check on all the cylinders?
Where are the sounds coming from?
An engine can get noisy due to lack of oil pressure, dilution of the oil by fuel or coolant, or because of a mechanical problem. All of these possibilities are serious, so you need to determine the source ASAP.
Engine noises also commonly end up being a failing accessory like a waterpump, power-steering pump, or alternator.
Free-revving when in gear can be from a slipping transmission or a failing torque converter. I don't know exactly what symptom you're experiencing from your description so far. Best bet is to have an experienced mechanic check it out ASAP.
FYI, your initial timing will be fine at anything between 5* and 15* BTDC.
Typical vacuum advance will add between 10* and 15* to this number at idle when full manifold vacuum is applied to the distributor.
At idle, and advance of between 25* and 30* (combined initial + vacuum) is fine.
The centrifugal advance should add in another 15* to 20* of advance to give you 30* to 35* total at WOT (initial + centrifugal). Vacuum advance shouldn't be applied at WOT.
I'm pretty sure most modern replacement waterpumps have sealed bearings, so running straight water in the summer should not cause any problems as long as your cooling system is holding pressure. A leak will reduce pressure (more than you think) and allow the coolant to boil, which will puke fluid and also cause you to run hot. Have you checked the operation of your waterpump?
With the tstat removed, you should be able to look down into your radiator through the cap hole and watch the water flowing through quickly. If not, it is possible that the pump is bad, or the wrong pump was used, for instance a reverse rotation pump used in a clockwise rotation application.
Sometimes it helps to eliminate possible sources of vacuum leaks for troubleshooting purposes. I like to plug off sources for the power brakes, the PCV system, and any other vacuum supply to narrow down possibilities.
Keep in mind that wire connections can look good, but still be bad causing intermittent misfires, charging problems, or dying. On a 3rdgen, the fusable link wires going down to the starter are about the poorest quality of wire you will ever see. The strands break internally under the insulation so you never see it. Some people will let the starter hang from the wires when removing it, and that often breaks the wire strands. Fusable links themselves can go bad from heat damage and/or corrosion. Battery cables can corrode under the insulation as well as be damaged by exhaust heat.
For troubleshooting I like to use heavy gauge jumper cables to connect the negative on the battery straight to the engine block. If this cures the starting problem, then you had a weak ground, like the grounding strap mentioned. If you're careful you can also hook the jumper from the battery positive to the post on the starter to test the positive cable.
You can test charging voltage with a $5 DVOM.
As mentioned backfiring often blows out the power valves on Holley type carburetors, and that can cause fueling problems, namely an excessively rich condition that can foul the plugs.
Are they fouling? What is your manifold vacuum reading like?
Have you done a compression check on all the cylinders?
Where are the sounds coming from?
An engine can get noisy due to lack of oil pressure, dilution of the oil by fuel or coolant, or because of a mechanical problem. All of these possibilities are serious, so you need to determine the source ASAP.
Engine noises also commonly end up being a failing accessory like a waterpump, power-steering pump, or alternator.
Free-revving when in gear can be from a slipping transmission or a failing torque converter. I don't know exactly what symptom you're experiencing from your description so far. Best bet is to have an experienced mechanic check it out ASAP.
FYI, your initial timing will be fine at anything between 5* and 15* BTDC.
Typical vacuum advance will add between 10* and 15* to this number at idle when full manifold vacuum is applied to the distributor.
At idle, and advance of between 25* and 30* (combined initial + vacuum) is fine.
The centrifugal advance should add in another 15* to 20* of advance to give you 30* to 35* total at WOT (initial + centrifugal). Vacuum advance shouldn't be applied at WOT.
I'm pretty sure most modern replacement waterpumps have sealed bearings, so running straight water in the summer should not cause any problems as long as your cooling system is holding pressure. A leak will reduce pressure (more than you think) and allow the coolant to boil, which will puke fluid and also cause you to run hot. Have you checked the operation of your waterpump?
With the tstat removed, you should be able to look down into your radiator through the cap hole and watch the water flowing through quickly. If not, it is possible that the pump is bad, or the wrong pump was used, for instance a reverse rotation pump used in a clockwise rotation application.
Sometimes it helps to eliminate possible sources of vacuum leaks for troubleshooting purposes. I like to plug off sources for the power brakes, the PCV system, and any other vacuum supply to narrow down possibilities.
Keep in mind that wire connections can look good, but still be bad causing intermittent misfires, charging problems, or dying. On a 3rdgen, the fusable link wires going down to the starter are about the poorest quality of wire you will ever see. The strands break internally under the insulation so you never see it. Some people will let the starter hang from the wires when removing it, and that often breaks the wire strands. Fusable links themselves can go bad from heat damage and/or corrosion. Battery cables can corrode under the insulation as well as be damaged by exhaust heat.
For troubleshooting I like to use heavy gauge jumper cables to connect the negative on the battery straight to the engine block. If this cures the starting problem, then you had a weak ground, like the grounding strap mentioned. If you're careful you can also hook the jumper from the battery positive to the post on the starter to test the positive cable.
You can test charging voltage with a $5 DVOM.
As mentioned backfiring often blows out the power valves on Holley type carburetors, and that can cause fueling problems, namely an excessively rich condition that can foul the plugs.
What is your manifold vacuum reading like? I don't have a vacuum gauge yet so I'm not sure on that.
Have you done a compression check on all the cylinders? I did a compression test on the first cylinder driver & passenger side. They were within 10% of each other.
Where are the sounds coming from? The sound is coming from either under the valve covers or under the heads. I'm not sure. Sometimes it's quiet & only I can notice it because I know its there. Other times its really loud. It sounds like its really, really low on oil or like a piston is getting ready to shoot through the head.
I've got the timing down within a degree or two now, I did a lot of heavy searching & reading through the threads to get it right.
My water pump is good it flows great through the radiator. I also did a compression test on the radiator & no leaks. It's good.
I've got the vacuum all good too. All of the lines were open & crammed behind the master cylinder when I got the car. Now they're all hooked up & no leaks.
I'll have to go over the wires to the battery positive, ground & to the starter. They look good on the outside, but like you said, it could be bad on the inside. I'll have to go through the carb again too. Possibly rebuild it.
The car's going to the shop on Thurs so I'll let you all know exactly what the problem is. I just don't like taking it to the shop to find out it was a $25 job I could've done in my driveway that ends up costing me $200 at a mechanic.
Thanks again for all the help guys.
03-27-2010, 11:17 AM
#58
Re: I Need Serious Help ASAP
You should do the compression test on every cylinder. That's the preferred method and is most revealing of a cylinder problem.
Most single misfires will create a fouled plug or are caused by a fouled plug. The proper way to find it is to pull ALL of the sparkplugs and inspect the tips carefully. Also check for cracks in the ceramic insulators at the tips and on the backside of the plug where the wire attaches. Even a small crack will cause a misfire. Beginner mechanics often crack plugs during installation when tightening with a socket or dropping the plug on the garage floor. You may not have cracks, but you could have a fouled tip, black from oil or soot, or wet from fuel, causing a misfire. New or not is completely irrelevant with sparkplugs.
Doing these checks ahead of time could save you money at the mechanic's. Some mechanics hesitate to do thorough testing because they have to pass on the charges for their time, and thorough is expensive.
Most single misfires will create a fouled plug or are caused by a fouled plug. The proper way to find it is to pull ALL of the sparkplugs and inspect the tips carefully. Also check for cracks in the ceramic insulators at the tips and on the backside of the plug where the wire attaches. Even a small crack will cause a misfire. Beginner mechanics often crack plugs during installation when tightening with a socket or dropping the plug on the garage floor. You may not have cracks, but you could have a fouled tip, black from oil or soot, or wet from fuel, causing a misfire. New or not is completely irrelevant with sparkplugs.
Doing these checks ahead of time could save you money at the mechanic's. Some mechanics hesitate to do thorough testing because they have to pass on the charges for their time, and thorough is expensive.
03-27-2010, 09:12 PM
#59
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
You should do the compression test on every cylinder. That's the preferred method and is most revealing of a cylinder problem.
Most single misfires will create a fouled plug or are caused by a fouled plug. The proper way to find it is to pull ALL of the sparkplugs and inspect the tips carefully. Also check for cracks in the ceramic insulators at the tips and on the backside of the plug where the wire attaches. Even a small crack will cause a misfire. Beginner mechanics often crack plugs during installation when tightening with a socket or dropping the plug on the garage floor. You may not have cracks, but you could have a fouled tip, black from oil or soot, or wet from fuel, causing a misfire. New or not is completely irrelevant with sparkplugs.
Doing these checks ahead of time could save you money at the mechanic's. Some mechanics hesitate to do thorough testing because they have to pass on the charges for their time, and thorough is expensive.
Most single misfires will create a fouled plug or are caused by a fouled plug. The proper way to find it is to pull ALL of the sparkplugs and inspect the tips carefully. Also check for cracks in the ceramic insulators at the tips and on the backside of the plug where the wire attaches. Even a small crack will cause a misfire. Beginner mechanics often crack plugs during installation when tightening with a socket or dropping the plug on the garage floor. You may not have cracks, but you could have a fouled tip, black from oil or soot, or wet from fuel, causing a misfire. New or not is completely irrelevant with sparkplugs.
Doing these checks ahead of time could save you money at the mechanic's. Some mechanics hesitate to do thorough testing because they have to pass on the charges for their time, and thorough is expensive.
Also, I was trying to figure out my rear gears without pulling the cover. The number on the housing is GM 22522626. I found a thread that tells you to rotate the tire twice (open rear end) & count the revolutions the driveshaft makes. I did that & mine rotated 3.5 times. When I came back to figure out how to decipher that my friend deleted everything I was looking at. Any idea as to what the gearing is?
03-27-2010, 09:41 PM
#60
Re: I Need Serious Help ASAP
I was listening to it today & it's misfiring on cylinder 7. I'm deff going to take your advice & check over all of the plugs before it goes to the shop.
Also, I was trying to figure out my rear gears without pulling the cover. The number on the housing is GM 22522626. I found a thread that tells you to rotate the tire twice (open rear end) & count the revolutions the driveshaft makes. I did that & mine rotated 3.5 times. When I came back to figure out how to decipher that my friend deleted everything I was looking at. Any idea as to what the gearing is?
Also, I was trying to figure out my rear gears without pulling the cover. The number on the housing is GM 22522626. I found a thread that tells you to rotate the tire twice (open rear end) & count the revolutions the driveshaft makes. I did that & mine rotated 3.5 times. When I came back to figure out how to decipher that my friend deleted everything I was looking at. Any idea as to what the gearing is?
Many rears have a metal tag attached by one of the cover bolts, which has the ratio imprinted on it. Jacking the car off the ground and spinning the tire usually doesn't work, so don't bother.
Just drive down the road at 60 MPH in your 1-to-1 gear and note your engine speed. In a 700R-4 (or other 3-speed automatic) your 1:1 gear is 3rd. In a 5-speed your 1:1 gear is 4th.
Next park on a flat cement or asphalt surface and measure your rear tire diameter. Typical stock diameters range from 24" to 26" with 3rdgens.
The formula is:
RPM = (MPH * (gear ratio * 336)) / tire diameter in inches
or
((RPM / (gear ratio *336)) * tire diameter = MPH
In 3rd gear in a 700R-4 trans, a 2.73:1 rear gear, and a 26" diameter rear tire, at 60 MPH your engine will be turning 2117 RPM.
With 3.23:1 rear gears, at 60 MPH your engine would turn 2504 RPM in 3rd gear.
03-28-2010, 06:04 PM
#61
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
Many rears have a metal tag attached by one of the cover bolts, which has the ratio imprinted on it. Jacking the car off the ground and spinning the tire usually doesn't work, so don't bother.
Just drive down the road at 60 MPH in your 1-to-1 gear and note your engine speed. In a 700R-4 (or other 3-speed automatic) your 1:1 gear is 3rd. In a 5-speed your 1:1 gear is 4th.
Next park on a flat cement or asphalt surface and measure your rear tire diameter. Typical stock diameters range from 24" to 26" with 3rdgens.
The formula is:
RPM = (MPH * (gear ratio * 336)) / tire diameter in inches
or
((RPM / (gear ratio *336)) * tire diameter = MPH
In 3rd gear in a 700R-4 trans, a 2.73:1 rear gear, and a 26" diameter rear tire, at 60 MPH your engine will be turning 2117 RPM.
With 3.23:1 rear gears, at 60 MPH your engine would turn 2504 RPM in 3rd gear.
Just drive down the road at 60 MPH in your 1-to-1 gear and note your engine speed. In a 700R-4 (or other 3-speed automatic) your 1:1 gear is 3rd. In a 5-speed your 1:1 gear is 4th.
Next park on a flat cement or asphalt surface and measure your rear tire diameter. Typical stock diameters range from 24" to 26" with 3rdgens.
The formula is:
RPM = (MPH * (gear ratio * 336)) / tire diameter in inches
or
((RPM / (gear ratio *336)) * tire diameter = MPH
In 3rd gear in a 700R-4 trans, a 2.73:1 rear gear, and a 26" diameter rear tire, at 60 MPH your engine will be turning 2117 RPM.
With 3.23:1 rear gears, at 60 MPH your engine would turn 2504 RPM in 3rd gear.
03-29-2010, 02:37 PM
#62
Junior Member
Join Date: Apr 2009
Posts: 22
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1984 z28
Engine: 5.7 vortec crate
Transmission: 700r4
Re: I Need Serious Help ASAP
hey man. i had to replace a tranny and both cables for it one time. for the shift linkage put the e brake on and put the shifter in nuetral. now crawl under the car and disconnect the linkage on the left side of the tranny. put the tranny all the way in park(all the way to the front) then move it 3 clicks to the back. tighten it up and dont forget to check your linkage cable to make sure it isnt broken. if it is replace it(not difficult at all) now for your tv cable which is most likely the cause of it winding out. under neath your throttle cable on your carb is your tv cable that SHOULD be connected. push the button on the cable and push the cable in as far as you can with it still connected. now with the car OFF hold the button down again and move the throttle on the carb WITH YOUR HAND all the way to wot. it will adjust itself. you may still have to adjust it a notch or two in or out. but it should be really close. to make sure drive it down the road til it gets into 3rd gear, then floor the pedal and it should drop down a gear(passing gear). if it does then your pretty damn close. i cant remember which is which but i think if you go in one more notch w/ the cable it will shift sooner and vice versa. anyway give that a try and hopefully it will fix your transmission problems. also check your fluid idleing in park. and when you do smell to make sure its not burnt.
03-29-2010, 05:46 PM
#63
Member
Join Date: Aug 2009
Location: AZ
Posts: 332
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1978 Chevrolet impala
Engine: 350ci 300hp/356tq pace crate
Transmission: 700r4
Axle/Gears: 3.42 Yukon posi
Re: I Need Serious Help ASAP
Well if it smells like the tranny's cooking...the tranny's probably cooking :P
03-29-2010, 06:33 PM
#64
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
hey man. i had to replace a tranny and both cables for it one time. for the shift linkage put the e brake on and put the shifter in nuetral. now crawl under the car and disconnect the linkage on the left side of the tranny. put the tranny all the way in park(all the way to the front) then move it 3 clicks to the back. tighten it up and dont forget to check your linkage cable to make sure it isnt broken. if it is replace it(not difficult at all) now for your tv cable which is most likely the cause of it winding out. under neath your throttle cable on your carb is your tv cable that SHOULD be connected. push the button on the cable and push the cable in as far as you can with it still connected. now with the car OFF hold the button down again and move the throttle on the carb WITH YOUR HAND all the way to wot. it will adjust itself. you may still have to adjust it a notch or two in or out. but it should be really close. to make sure drive it down the road til it gets into 3rd gear, then floor the pedal and it should drop down a gear(passing gear). if it does then your pretty damn close. i cant remember which is which but i think if you go in one more notch w/ the cable it will shift sooner and vice versa. anyway give that a try and hopefully it will fix your transmission problems. also check your fluid idleing in park. and when you do smell to make sure its not burnt.
I'll try disconnecting & reconnecting the linkage & see what happens. As far as the TV cable goes, I only have one cable that comes from my firewall & connects to the carb...
03-30-2010, 07:27 PM
#65
Junior Member
Join Date: Apr 2009
Posts: 22
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1984 z28
Engine: 5.7 vortec crate
Transmission: 700r4
Re: I Need Serious Help ASAP
well that could be a big problem right there. there should be a cable that comes up from the passanger side of the tranny to the throttle. and it should be connected directly below the throttle cable on the carb. if its not that transmission is gonna cook if it hasnt already.
03-31-2010, 06:32 PM
#66
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
well that could be a big problem right there. there should be a cable that comes up from the passanger side of the tranny to the throttle. and it should be connected directly below the throttle cable on the carb. if its not that transmission is gonna cook if it hasnt already.
The only thing that comes off my tranny is the speedo cable, vacuum line & cable to my shifter...
03-31-2010, 07:25 PM
#67
Junior Member
Join Date: Apr 2009
Posts: 22
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1984 z28
Engine: 5.7 vortec crate
Transmission: 700r4
Re: I Need Serious Help ASAP
ya, thats a major problem then man. that cable controls your fluid pressure in your tranny. and your tranny will die without it. i found a pic of it, the one on the bottom is the tv cable.
03-31-2010, 07:55 PM
#69
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
03-31-2010, 08:22 PM
#70
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
Another quick question on the TV cable. I was reading somewhere that it was for trannys with overdrive. I don't have OD. Do I still need it?
04-01-2010, 04:00 AM
#71
Re: I Need Serious Help ASAP
A Turbo 350 or 400 does not have a TV cable. The 700R4 OD uses a TV cable. I would also suggest the following; the engine probably has hydraulic lifters - lash all of the valves. It is possible the PO excessively tightened. Performing a compression check on two cylinders is not sufficient, do all eight and confirm they are all within 10% or less. If you have not dropped the tranny pan yet now is a good time. Drain all of the tranny oil, wipe out the pan, replace the filter, pan gasket and add new tranny oil. Minimal money and time investment in tranny maintenance will either confirm tranny is shot or will possibly correct the problems. Manually place tranny in park under the car and adjust the cable. Ensure that the shifter operates the cable through the entire gear range. A new cable may be needed.
There has been some overall great advice offered for the TGO guys. I also encourage you to not give up. Some of the best vehicles I have owned started out the same way this car has for you. By the time you get through these situations you will know this car well and have gained a wealth of experience and knowledge. I have been working on vehicles for over 40 years and still appreciate the challenges.
There has been some overall great advice offered for the TGO guys. I also encourage you to not give up. Some of the best vehicles I have owned started out the same way this car has for you. By the time you get through these situations you will know this car well and have gained a wealth of experience and knowledge. I have been working on vehicles for over 40 years and still appreciate the challenges.
04-01-2010, 03:33 PM
#72
Re: I Need Serious Help ASAP
Some older transmissions like the th350 also use a TV cable, but it's better known as the "kickdown cable".
Transmissions that don't use a kickdown cable use a vacuum modulator to do the same thing. Your vacuum line must be made of metal for most of the distance to prevent collapse. The end couplers can be a stiff rubber.
Just get under your car and carefully check out what you've got before assuming too much.
04-01-2010, 06:12 PM
#73
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
A Turbo 350 or 400 does not have a TV cable. The 700R4 OD uses a TV cable. I would also suggest the following; the engine probably has hydraulic lifters - lash all of the valves. It is possible the PO excessively tightened. Performing a compression check on two cylinders is not sufficient, do all eight and confirm they are all within 10% or less. If you have not dropped the tranny pan yet now is a good time. Drain all of the tranny oil, wipe out the pan, replace the filter, pan gasket and add new tranny oil. Minimal money and time investment in tranny maintenance will either confirm tranny is shot or will possibly correct the problems. Manually place tranny in park under the car and adjust the cable. Ensure that the shifter operates the cable through the entire gear range. A new cable may be needed.
There has been some overall great advice offered for the TGO guys. I also encourage you to not give up. Some of the best vehicles I have owned started out the same way this car has for you. By the time you get through these situations you will know this car well and have gained a wealth of experience and knowledge. I have been working on vehicles for over 40 years and still appreciate the challenges.
There has been some overall great advice offered for the TGO guys. I also encourage you to not give up. Some of the best vehicles I have owned started out the same way this car has for you. By the time you get through these situations you will know this car well and have gained a wealth of experience and knowledge. I have been working on vehicles for over 40 years and still appreciate the challenges.
tool if need be. I'm off the next 2 days so under the car I go...A transmission needs to sense engine load in order to adjust line pressure and part throttle shifting points. The th700R4 uses a TV cable attached to the throttle for this.
Some older transmissions like the th350 also use a TV cable, but it's better known as the "kickdown cable".
Transmissions that don't use a kickdown cable use a vacuum modulator to do the same thing. Your vacuum line must be made of metal for most of the distance to prevent collapse. The end couplers can be a stiff rubber.
Just get under your car and carefully check out what you've got before assuming too much.
Some older transmissions like the th350 also use a TV cable, but it's better known as the "kickdown cable".
Transmissions that don't use a kickdown cable use a vacuum modulator to do the same thing. Your vacuum line must be made of metal for most of the distance to prevent collapse. The end couplers can be a stiff rubber.
Just get under your car and carefully check out what you've got before assuming too much.
04-01-2010, 08:58 PM
#74
Re: I Need Serious Help ASAP
I believe I have the kickdown cable. If I didn't, when I mashed the gas the tranny would never downshift right? It downshifts when I mash the gas. As far as the vacuum modulator goes I have a rubber hose that goes from the modulator itself to the back of the carb/intake. No metal & it's not a stiff rubber...
You need to re-run your line to the modulator and make sure there are no vacuum leaks.
04-02-2010, 01:35 AM
#75
Member
Join Date: Aug 2009
Location: AZ
Posts: 332
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1978 Chevrolet impala
Engine: 350ci 300hp/356tq pace crate
Transmission: 700r4
Axle/Gears: 3.42 Yukon posi
Re: I Need Serious Help ASAP
Okay, IF you have a TV cable (Not sure myself, haven't done much research on chevy auto trannies) it will be VERY easy to spot.
It should essentially look like a second throttle cable.
It should essentially look like a second throttle cable.
04-02-2010, 09:23 AM
#76
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
A kickdown cable would go from the transmission (near the valve body) up to your throttle lever on your carburetor. I don't know why you would have both kickdown and a modulator. They do the same job.
You need to re-run your line to the modulator and make sure there are no vacuum leaks.
You need to re-run your line to the modulator and make sure there are no vacuum leaks.
04-02-2010, 10:09 AM
#77
Junior Member
Join Date: Mar 2010
Location: Philly, PA
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1982 Z28
Engine: Stock 305 4BBL - New QJet
Transmission: 700R4
Axle/Gears: Stock
Re: I Need Serious Help ASAP
betting on the altenator! check connections...or remove and get tested! but then again...what do i know?!
04-03-2010, 08:04 AM
#79
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
Vacuum IS installed & working right.
04-03-2010, 08:07 AM
#80
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
BAD NEWS GUYS. I went to my mechanic to get the timing & carb tuned correctly. While there I explained what the car's been doing & let him listen to it/drive it. He said it's AT LEAST my crank & oil pump that are going out...Now my question to you all is this, Should I just sell it ASAP to some kid & get another 3rd Gen or should I rebuild the motor?
04-03-2010, 03:59 PM
#81
Member
Join Date: Aug 2009
Location: AZ
Posts: 332
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1978 Chevrolet impala
Engine: 350ci 300hp/356tq pace crate
Transmission: 700r4
Axle/Gears: 3.42 Yukon posi
Re: I Need Serious Help ASAP
How well do you know this mechanic?
I'm not saying it's impossible...but it's definitely improbable.
I'm not saying it's impossible...but it's definitely improbable.
04-03-2010, 06:00 PM
#82
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
04-14-2010, 05:48 PM
#83
Junior Member
Thread Starter
Join Date: Jul 2008
Location: Maitland, FL
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Car: 84 T/A
Engine: 400
Transmission: Turbo 350
Re: I Need Serious Help ASAP
Car's sold. Turns out my mechanic was wrong. Took it to another shop. They tore it down & found the pushrods were bent, rockers & harmonic balancer were shot. They said tranny was fine too. The linkage was just off a gear.
Thread
Thread Starter
Forum
Replies
Last Post
