Engine running ruff after setting 78 L82
Thread Starter
Burning Brakes
Joined: Jul 2017
Posts: 1,114
Likes: 149
From: Frisco TX
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,174
Likes: 9,298
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
If you have the original distributor you wont have HEI unless its pertronix or something...
Sitting usually will cause gas to go bad, rubber lines to crack, and things to rust.
bad gas is obvious, just give it a sniff, maybe check for goo in your tank with a flashilight.
take off the distributor cap and check your points and condensor for corrosion or build up on the contacts, usually a little skuff or cleaning will clean them up
rust or corrosion on the cap and rotor
check your vacuum lines for your brake vacuum if you have power brakes and you vacuum line for your vacuum advance
get your timing light and check your timing to see if your advance is stuck
depending on your carb you might have a stuck float and you might be flooding or running extremely rich.
Sitting usually will cause gas to go bad, rubber lines to crack, and things to rust.
bad gas is obvious, just give it a sniff, maybe check for goo in your tank with a flashilight.
take off the distributor cap and check your points and condensor for corrosion or build up on the contacts, usually a little skuff or cleaning will clean them up
rust or corrosion on the cap and rotor
check your vacuum lines for your brake vacuum if you have power brakes and you vacuum line for your vacuum advance
get your timing light and check your timing to see if your advance is stuck
depending on your carb you might have a stuck float and you might be flooding or running extremely rich.
Thread Starter
Burning Brakes
Joined: Jul 2017
Posts: 1,114
Likes: 149
From: Frisco TX
If you have the original distributor you wont have HEI unless its pertronix or something...
Sitting usually will cause gas to go bad, rubber lines to crack, and things to rust.
bad gas is obvious, just give it a sniff, maybe check for goo in your tank with a flashilight.
take off the distributor cap and check your points and condensor for corrosion or build up on the contacts, usually a little skuff or cleaning will clean them up
rust or corrosion on the cap and rotor
check your vacuum lines for your brake vacuum if you have power brakes and you vacuum line for your vacuum advance
get your timing light and check your timing to see if your advance is stuck
depending on your carb you might have a stuck float and you might be flooding or running extremely rich.
Sitting usually will cause gas to go bad, rubber lines to crack, and things to rust.
bad gas is obvious, just give it a sniff, maybe check for goo in your tank with a flashilight.
take off the distributor cap and check your points and condensor for corrosion or build up on the contacts, usually a little skuff or cleaning will clean them up
rust or corrosion on the cap and rotor
check your vacuum lines for your brake vacuum if you have power brakes and you vacuum line for your vacuum advance
get your timing light and check your timing to see if your advance is stuck
depending on your carb you might have a stuck float and you might be flooding or running extremely rich.
Mine is a 78 so it has the HEI from the factory. I put a new HEI in about 25 years ago.
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,174
Likes: 9,298
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
I misread it I thought it said 71...I hear those HEI modules go bad all the time,
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
No one asked, so I will.
How far did you drive it? Mile? 10 miles? Two blocks?
The reason I ask is, today was my last Vette ride for the season. Somewhat like yours, mine has been sitting since Labor Day due to busy business issues.
My first mile was awful. Sputter, spit, miss, ran like crap.
Second mile, things got better. Maybe firing on 6 now.
By the third mile, completely fixed itself and was running like a scalded dog.
I too had a gasoline supplement in the tank. Bad not fresh gas, which was where I was headed to.
Anyway Len, maybe give it some more time (miles) to recoup.
How far did you drive it? Mile? 10 miles? Two blocks?
The reason I ask is, today was my last Vette ride for the season. Somewhat like yours, mine has been sitting since Labor Day due to busy business issues.
My first mile was awful. Sputter, spit, miss, ran like crap.
Second mile, things got better. Maybe firing on 6 now.
By the third mile, completely fixed itself and was running like a scalded dog.
I too had a gasoline supplement in the tank. Bad not fresh gas, which was where I was headed to.
Anyway Len, maybe give it some more time (miles) to recoup.
Thread Starter
Burning Brakes
Joined: Jul 2017
Posts: 1,114
Likes: 149
From: Frisco TX
No one asked, so I will.
How far did you drive it? Mile? 10 miles? Two blocks?
The reason I ask is, today was my last Vette ride for the season. Somewhat like yours, mine has been sitting since Labor Day due to busy business issues.
My first mile was awful. Sputter, spit, miss, ran like crap.
Second mile, things got better. Maybe firing on 6 now.
By the third mile, completely fixed itself and was running like a scalded dog.
I too had a gasoline supplement in the tank. Bad not fresh gas, which was where I was headed to.
Anyway Len, maybe give it some more time (miles) to recoup.
How far did you drive it? Mile? 10 miles? Two blocks?
The reason I ask is, today was my last Vette ride for the season. Somewhat like yours, mine has been sitting since Labor Day due to busy business issues.
My first mile was awful. Sputter, spit, miss, ran like crap.
Second mile, things got better. Maybe firing on 6 now.
By the third mile, completely fixed itself and was running like a scalded dog.
I too had a gasoline supplement in the tank. Bad not fresh gas, which was where I was headed to.
Anyway Len, maybe give it some more time (miles) to recoup.
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Safety Car
Joined: May 2001
Posts: 4,750
Likes: 1,642
From: Fairfax Virginia
I would still check for any sparks under the hood in the dark. Your misses might be caused by a shorted plug wire and as they shake around they leak to the nearest ground. I had year old wires from MSD and they leaked everywhere it seemed. A simple inspection in the dark will tell you if the spark plug wires are leaking.
My wife's Pickup had a higher power MSD coil that I put on top ensure a good burn at the plugs. It backfired on me when I had to replace the distributor caps due to Carbon Tracking that effectively shorts at the inside of the cap. New cap and it ran great, a few months later and it was running poorly due to misfires. Carbon tracking can be seen using a Black light and appears like little webs inside the distributor cap.
One additional point, Do NOT use Die-electric Grease on any electrical wire connections. One Forum member used Die-Electric on every connection and had all sorts of electrical gremlins.
Die-Electric grease IS NOT CONDUCTIVE. Battery grease IS Conductive and keeps oxygen from getting to the protected parts and causes no problems.
The correct use for Die-Electric grease is to keep the Rubber boots on the spark plug wires from sticking to the plug and breaking the wire. DO not use it between the spark plug cap contact and the spark plug terminal as it will inhibit the firing of that cylinder.
My wife's Pickup had a higher power MSD coil that I put on top ensure a good burn at the plugs. It backfired on me when I had to replace the distributor caps due to Carbon Tracking that effectively shorts at the inside of the cap. New cap and it ran great, a few months later and it was running poorly due to misfires. Carbon tracking can be seen using a Black light and appears like little webs inside the distributor cap.
One additional point, Do NOT use Die-electric Grease on any electrical wire connections. One Forum member used Die-Electric on every connection and had all sorts of electrical gremlins.
Die-Electric grease IS NOT CONDUCTIVE. Battery grease IS Conductive and keeps oxygen from getting to the protected parts and causes no problems.
The correct use for Die-Electric grease is to keep the Rubber boots on the spark plug wires from sticking to the plug and breaking the wire. DO not use it between the spark plug cap contact and the spark plug terminal as it will inhibit the firing of that cylinder.
Thread Starter
Burning Brakes
Joined: Jul 2017
Posts: 1,114
Likes: 149
From: Frisco TX
I would still check for any sparks under the hood in the dark. Your misses might be caused by a shorted plug wire and as they shake around they leak to the nearest ground. I had year old wires from MSD and they leaked everywhere it seemed. A simple inspection in the dark will tell you if the spark plug wires are leaking.
My wife's Pickup had a higher power MSD coil that I put on top ensure a good burn at the plugs. It backfired on me when I had to replace the distributor caps due to Carbon Tracking that effectively shorts at the inside of the cap. New cap and it ran great, a few months later and it was running poorly due to misfires. Carbon tracking can be seen using a Black light and appears like little webs inside the distributor cap.
One additional point, Do NOT use Die-electric Grease on any electrical wire connections. One Forum member used Die-Electric on every connection and had all sorts of electrical gremlins.
Die-Electric grease IS NOT CONDUCTIVE. Battery grease IS Conductive and keeps oxygen from getting to the protected parts and causes no problems.
The correct use for Die-Electric grease is to keep the Rubber boots on the spark plug wires from sticking to the plug and breaking the wire. DO not use it between the spark plug cap contact and the spark plug terminal as it will inhibit the firing of that cylinder.
My wife's Pickup had a higher power MSD coil that I put on top ensure a good burn at the plugs. It backfired on me when I had to replace the distributor caps due to Carbon Tracking that effectively shorts at the inside of the cap. New cap and it ran great, a few months later and it was running poorly due to misfires. Carbon tracking can be seen using a Black light and appears like little webs inside the distributor cap.
One additional point, Do NOT use Die-electric Grease on any electrical wire connections. One Forum member used Die-Electric on every connection and had all sorts of electrical gremlins.
Die-Electric grease IS NOT CONDUCTIVE. Battery grease IS Conductive and keeps oxygen from getting to the protected parts and causes no problems.
The correct use for Die-Electric grease is to keep the Rubber boots on the spark plug wires from sticking to the plug and breaking the wire. DO not use it between the spark plug cap contact and the spark plug terminal as it will inhibit the firing of that cylinder.
Thread Starter
Burning Brakes
Joined: Jul 2017
Posts: 1,114
Likes: 149
From: Frisco TX
I tried removing some plugs on the left side. They wouldn't budge. I have aluminum heads so I was reluctant to use more pressure for fear of galling the spark plug threads.
I might try testing the coil today with the ohm meter to see what it says.
I might try testing the coil today with the ohm meter to see what it says.
Last edited by LenWoodruff; Oct 31, 2024 at 11:02 AM.
Safety Car
Joined: May 2001
Posts: 4,750
Likes: 1,642
From: Fairfax Virginia
Be very careful with your aluminum heads and Steel spark plugs! I always use a form of thinner anti-seize made by Champion Spark plugs for this use. Aluminum and Steel are not friendly to each other. It is so easy to pull the threads out of the hole. You need to use the anti-seize and use it often.
Thick anti-seize will work but gets sloppy so I use the Champion brand Thinner Spark Plug Anti-seize which is very easy to find at a good auto store. You simply brush some on the spark plugs and then screw them back in.
Whatever you use DO NOT USE Copper anti-seize as Copper and Aluminum are a bad combination. I lived on a 36' boat while in college. My neighbor bought a new Aluminum Sears 12' row boat for a dinghy and right away taped off his new water line and promptly painted the bottom of his aluminum boat with Copper Bottom paint. The next morning we could push our fingers through the hull wherever he painted it. The old guy was an old Navy Salty dog and he never knew about mixing copper and aluminum. I have Soft Copper header gaskets my cast iron heads with no problem. If I used Copper gaskets on my 1988 C4 with aluminum heads it would be another story and not a pretty one.
Thick anti-seize will work but gets sloppy so I use the Champion brand Thinner Spark Plug Anti-seize which is very easy to find at a good auto store. You simply brush some on the spark plugs and then screw them back in.
Whatever you use DO NOT USE Copper anti-seize as Copper and Aluminum are a bad combination. I lived on a 36' boat while in college. My neighbor bought a new Aluminum Sears 12' row boat for a dinghy and right away taped off his new water line and promptly painted the bottom of his aluminum boat with Copper Bottom paint. The next morning we could push our fingers through the hull wherever he painted it. The old guy was an old Navy Salty dog and he never knew about mixing copper and aluminum. I have Soft Copper header gaskets my cast iron heads with no problem. If I used Copper gaskets on my 1988 C4 with aluminum heads it would be another story and not a pretty one.
Thread Starter
Burning Brakes
Joined: Jul 2017
Posts: 1,114
Likes: 149
From: Frisco TX
Be very careful with your aluminum heads and Steel spark plugs! I always use a form of thinner anti-seize made by Champion Spark plugs for this use. Aluminum and Steel are not friendly to each other. It is so easy to pull the threads out of the hole. You need to use the anti-seize and use it often.
Thick anti-seize will work but gets sloppy so I use the Champion brand Thinner Spark Plug Anti-seize which is very easy to find at a good auto store. You simply brush some on the spark plugs and then screw them back in.
Whatever you use DO NOT USE Copper anti-seize as Copper and Aluminum are a bad combination. I lived on a 36' boat while in college. My neighbor bought a new Aluminum Sears 12' row boat for a dinghy and right away taped off his new water line and promptly painted the bottom of his aluminum boat with Copper Bottom paint. The next morning we could push our fingers through the hull wherever he painted it. The old guy was an old Navy Salty dog and he never knew about mixing copper and aluminum. I have Soft Copper header gaskets my cast iron heads with no problem. If I used Copper gaskets on my 1988 C4 with aluminum heads it would be another story and not a pretty one.
Thick anti-seize will work but gets sloppy so I use the Champion brand Thinner Spark Plug Anti-seize which is very easy to find at a good auto store. You simply brush some on the spark plugs and then screw them back in.
Whatever you use DO NOT USE Copper anti-seize as Copper and Aluminum are a bad combination. I lived on a 36' boat while in college. My neighbor bought a new Aluminum Sears 12' row boat for a dinghy and right away taped off his new water line and promptly painted the bottom of his aluminum boat with Copper Bottom paint. The next morning we could push our fingers through the hull wherever he painted it. The old guy was an old Navy Salty dog and he never knew about mixing copper and aluminum. I have Soft Copper header gaskets my cast iron heads with no problem. If I used Copper gaskets on my 1988 C4 with aluminum heads it would be another story and not a pretty one.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,051
Likes: 4,194
From: US-PNW
Your cap and rotor could use a clean up. Use a fine file (an old-school distributor file for points would be good) and file the pitting/surface buildup on the rotor tip and each cap tip. A fingernail file would also work, but don't use an emery board - a diamond file would be fine. Pry the rotor button upwards and clean that too with a little steel wool or the file to get a shiny surface.
Not saying this will fix your problem as it sounds like more than just dirty, corroded rotor and cap terminals, but it's good maintenance.
Thread Starter
Burning Brakes
Joined: Jul 2017
Posts: 1,114
Likes: 149
From: Frisco TX
First the plugs: try running the engine for about 3-4 minutes to put some heat into the aluminum to expand it, then see if you can get the plugs out. The aluminum will expand more (and more quickly) than the steel of the plugs.
Your cap and rotor could use a clean up. Use a fine file (an old-school distributor file for points would be good) and file the pitting/surface buildup on the rotor tip and each cap tip. A fingernail file would also work, but don't use an emery board - a diamond file would be fine. Pry the rotor button upwards and clean that too with a little steel wool or the file to get a shiny surface.
Not saying this will fix your problem as it sounds like more than just dirty, corroded rotor and cap terminals, but it's good maintenance.
Your cap and rotor could use a clean up. Use a fine file (an old-school distributor file for points would be good) and file the pitting/surface buildup on the rotor tip and each cap tip. A fingernail file would also work, but don't use an emery board - a diamond file would be fine. Pry the rotor button upwards and clean that too with a little steel wool or the file to get a shiny surface.
Not saying this will fix your problem as it sounds like more than just dirty, corroded rotor and cap terminals, but it's good maintenance.
I will pull file out and try it.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Len,
That rotor looks terrible. It has been burning / arcing.
I would question which Spring Bushing is the dizzy cap. There are two types of bushing springs and most new caps from MSD should come with both choices.
There is a Low Resistance Bushing and a High Resistance Bushing.
Some new dizzy caps come w/ High Res only. And that maybe your "rotor" issue.
Its an easy swap by removing coil dust cover, coil and rubber washer under the coil. Then access to the bushing is easy.
That rotor looks terrible. It has been burning / arcing.
I would question which Spring Bushing is the dizzy cap. There are two types of bushing springs and most new caps from MSD should come with both choices.
There is a Low Resistance Bushing and a High Resistance Bushing.
Some new dizzy caps come w/ High Res only. And that maybe your "rotor" issue.
Its an easy swap by removing coil dust cover, coil and rubber washer under the coil. Then access to the bushing is easy.
Thread Starter
Burning Brakes
Joined: Jul 2017
Posts: 1,114
Likes: 149
From: Frisco TX
Len,
That rotor looks terrible. It has been burning / arcing.
I would question which Spring Bushing is the dizzy cap. There are two types of bushing springs and most new caps from MSD should come with both choices.
There is a Low Resistance Bushing and a High Resistance Bushing.
Some new dizzy caps come w/ High Res only. And that maybe your "rotor" issue.
Its an easy swap by removing coil dust cover, coil and rubber washer under the coil. Then access to the bushing is easy.
That rotor looks terrible. It has been burning / arcing.
I would question which Spring Bushing is the dizzy cap. There are two types of bushing springs and most new caps from MSD should come with both choices.
There is a Low Resistance Bushing and a High Resistance Bushing.
Some new dizzy caps come w/ High Res only. And that maybe your "rotor" issue.
Its an easy swap by removing coil dust cover, coil and rubber washer under the coil. Then access to the bushing is easy.
This was a new distributor from Jegs about 25 years ago. It's been running fine up until a few days ago.
