Did I mess something up?
Thread Starter
Drifting
Joined: Jul 2020
Posts: 1,501
Likes: 323
From: San Diego
Did I mess something up?
I have a brand new 383 Stroker with and MSD ignition in my 1968. It was broken in a on a dyno and I have put about 1,000 miles on it since. She runs really good and strong but today I was pulling out onto my main street near my house and did a strong pull in 1st and 2nd gear to just short of redline. I looked in the rear view mirror and noticed a big puff of white smoke come out of my right side pipe and when I pulled up to a traffic light about 1/4 mile away the car was running rough and almost died. I kept revving the gas a little and she seemed to come back alive and then ran fine without any issues for the 25 miles to work. Is there anything I should look at or any issues you think it may have?
Melting Slicks
Joined: Feb 2017
Posts: 3,232
Likes: 1,232
From: PHX AZ
White smoke is Anti-freeze/water (vapor)
Blue smoke is oil burning
Black smoke..waaay too rich or someone slipped a diesel in there overnite.
Try this test (old school mechanics 101)
Car in driveway. E brake on!
Warm engine;
Rev car to 3000 rpm and keep it there for a minute. (low vacuum)
At one minute ABRUPTLY remove foot from accel pedal. HIGH VACUUM
IMMEDIATELY as it comes back to idle, Jump on the throttle abruptly BACK to 3000 RPM for one second. LOW VACUUM
LOOK AT THE TAIL PIPES (or have a trusted mechanical friend stand behind car) SOME COLOR COULD BELCH OUT OF THE PIPES.....
If nothing happens all is good!
REPORT FINDINGS.
This test tells you if you have a bad head gasket, leaking head bolts, bad rings (not seated yet), bad valve guides, mal adjusted carb etc.
good luck
Unkahal
Blue smoke is oil burning
Black smoke..waaay too rich or someone slipped a diesel in there overnite.
Try this test (old school mechanics 101)
Car in driveway. E brake on!
Warm engine;
Rev car to 3000 rpm and keep it there for a minute. (low vacuum)
At one minute ABRUPTLY remove foot from accel pedal. HIGH VACUUM
IMMEDIATELY as it comes back to idle, Jump on the throttle abruptly BACK to 3000 RPM for one second. LOW VACUUM
LOOK AT THE TAIL PIPES (or have a trusted mechanical friend stand behind car) SOME COLOR COULD BELCH OUT OF THE PIPES.....
If nothing happens all is good!
REPORT FINDINGS.
This test tells you if you have a bad head gasket, leaking head bolts, bad rings (not seated yet), bad valve guides, mal adjusted carb etc.
good luck
Unkahal
Thread Starter
Drifting
Joined: Jul 2020
Posts: 1,501
Likes: 323
From: San Diego
I recently pressure tested the radiator up to about 18 psi and it held for over 3 hours so I dont think its a blown head gasket.
I tend to think its running either too lean or too rich because if I start it in the garage (with the garage door open) I have to walk out because my eyes and throat start to burn after a minute or two.
I tend to think its running either too lean or too rich because if I start it in the garage (with the garage door open) I have to walk out because my eyes and throat start to burn after a minute or two.
Melting Slicks
Joined: Feb 2017
Posts: 3,232
Likes: 1,232
From: PHX AZ
So it was black smoke you saw...probably either incorrect jets (non M4MV) or incorrect float level.
Tuning a Rochester quickly;
Turn idle stop screws in while car is warm and running
Turn one at a time IN until lean stumble (you'll hear it and feel it) Back out 1/4 turn
Do the other one same way
Drive!
Unkahal
Tuning a Rochester quickly;
Turn idle stop screws in while car is warm and running
Turn one at a time IN until lean stumble (you'll hear it and feel it) Back out 1/4 turn
Do the other one same way
Drive!
Unkahal
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Thread Starter
Drifting
Joined: Jul 2020
Posts: 1,501
Likes: 323
From: San Diego
I was thinking about the tire smoke but the car didnt seem to get out of line. The gas sloshing in the bowl could be why it was running rough at the light. Thanks for the help. But…what is an extension?
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,212
Likes: 9,350
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 recently pressure tested the radiator up to about 18 psi and it held for over 3 hours so I dont think its a blown head gasket.
I tend to think its running either too lean or too rich because if I start it in the garage (with the garage door open) I have to walk out because my eyes and throat start to burn after a minute or two.
I tend to think its running either too lean or too rich because if I start it in the garage (with the garage door open) I have to walk out because my eyes and throat start to burn after a minute or two.
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,212
Likes: 9,350
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
https://www.racingjunk.com/news/back...nsions-slide-1
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,212
Likes: 9,350
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
Race Director
Joined: Mar 2016
Posts: 14,402
Likes: 8,209
From: Napa Valley California
How long did you warm it up before you blasted down the street at near redline?
Could simply be that the engine was still cold and the choke was still open, then your mashing on the go fast pedal.
The plugs could have been wet from too much fuel and it took a little time to clean them off.
Unlike engines with electronic fuel injection, carbureted engines need to be throughly warmed up before running them hard.
The white smoke you saw, could have simply been condensation steaming out of the exhaust.
If it’s been running fine and it is now, leave it alone, especially if it was professionally tuned on a dyno.
Could simply be that the engine was still cold and the choke was still open, then your mashing on the go fast pedal.
The plugs could have been wet from too much fuel and it took a little time to clean them off.
Unlike engines with electronic fuel injection, carbureted engines need to be throughly warmed up before running them hard.
The white smoke you saw, could have simply been condensation steaming out of the exhaust.
If it’s been running fine and it is now, leave it alone, especially if it was professionally tuned on a dyno.