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Discussion Starter #1
I didn't want to bug the experts here on Trifive, so I was trying to get Edelbrock to solve my problem. I have a '62 327ci, 335 hp with 385 ft lbs torque. It has a mid performance Lunati roller cam. 2.5" exhaust and a 600 cfm Edelbrock 1406 carb . It has an electric choke. No power brakes, steering or AC.
It is a high revver at slow speed, as it red lines at about 5600rpm. My problem is that when I start it, it idles great, but when I'm on the road and I come to a stop, the engine stalls and dies. I can start it immediately and it will go back to a perfect idle...until the next stop. I can gun it, and it goes back to idle, no stall. We've adjusted gas and float levels, changed filter and changed fuel pump. My gas cap is a vent type with the little check valve so as not to create a vacuum.
Valve seats are not ported but they have been "cleaned" with hardened seats and roller tipped rockers. Could the problem be cam/valve related?
Thanks,
Bob
 

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are you running ported or manifold vacuum for the vac advance? if manifold try ported.
 

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Discussion Starter #4 (Edited)
are you running ported or manifold vacuum for the vac advance? if manifold try ported.
John, that's a good question. I don't think the 327 in question has a vacuum advance. It is on my '62 Vette. The other 327 pictured is on my black '56 Chevy. It is also a '62 327. They both have Edelbrock 1406 600cfm carb.
The Chevy has a small tube going from the carb to the V/A, and a larger tube going from the front of the carb to a port on the valve cover.
The Corvette carb has only the down draft tube going to a port on the back of the carb, No tubes in front. They're capped off.
They both have Pertronix electronic ignition. Pic #1 is the Chevy 327. Pic 2 & 3 are of the Vette.
Bob

Chevy 327 Carb 3.JPG

Chevy 327 Carb 2.JPG

Chevy 327 Carb 1.JPG
 

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Put the clutch down when you stop...:sign0020: just kidding. forgot to mention what transmission there is.
 

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Discussion Starter #6
Put the clutch down when you stop...:sign0020: just kidding. forgot to mention what transmission there is.
Three on the tree with overdrive on the Chev, 4sp Muncie on the Vette. Chev and Vette both have a 3.55 rear end.
Bob
 

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Make sure your accelerator pump is working and adjusted properly. Also what fuel pump are you using? If your pump has more then 5 or 6 psi get a regulator and set it at no more then 6 psi. As a side note... You should get a insulator gasket for the carb too. It will make a huge difference in not boiling the fuel in the carb.
Todd
 

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Also can you post a picture of the drivers side of your carb. It looks like your accelerator pump linkage is in the bottom hole. But it's hard to tell on my phone.
Todd
 

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NO vacuum advance on the Corvette




 

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Discussion Starter #10
According to my mechanic he sez if the original distributor came without a vacuum advance, then it doesn't need one, and he sez the original 340 horse 327's came without one.
We installed the down spout hose where Pop's picture shows the PB vacuum line should go. It shows it should be going in front next to the V/A ports. Will this make a difference?
Bob
 

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Discussion Starter #11
Also can you post a picture of the drivers side of your carb. It looks like your accelerator pump linkage is in the bottom hole. But it's hard to tell on my phone.
Todd
Todd, what you are suggesting is vapor lock. I know about vapor lock, and this problem is not vapor lock.
Took a couple more pics. Not very good...sorry.
Bob

Chevy 327 Carb 4.JPG

Chevy 327 Carb 5.JPG
 

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Your pictures are fine. Try moving your linkage to the top hole on the accelerator pump linkage. See if that helps stop the stalling.
Symptom of a faulty accelerator pump is engine sputtering or stalling. The sputtering is caused by the lack of fuel that is supposed to be provided by the accelerator pump when throttle is rapidly pressed. In more serious cases of accelerator pump failure, rapidly pressing on the gas may cause the engine to stall, again due to the lean condition that can be created when the accelerator pump is not working.
Todd
 

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The first thing to do is check for vacuum leaks. The next thing to do is to see if adjusting the idle mixture helps. Next thing to try would be to increase the idle speed slightly. These are basic carburetor things, unspecific to an Edelbrock carb. The next thing to do is to check the ignition timing. Again, generic tuning. Keep it simple until you rule out all the simple things.
 

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Discussion Starter #14
The first thing to do is check for vacuum leaks. The next thing to do is to see if adjusting the idle mixture helps. Next thing to try would be to increase the idle speed slightly. These are basic carburetor things, unspecific to an Edelbrock carb. The next thing to do is to check the ignition timing. Again, generic tuning. Keep it simple until you rule out all the simple things.
Done all the basic stuff Rick. One thing that concerns me is that the down tube is connected to the port on the back of the carb identified as being for Pwr Brks. The front port identified as being for the PCV tube is capped off. I don't use the vacuum ports as the early 340 hp 327's didn't use vacuum advance. I'm not even using a PCV valve.
The smaller 327's used a vacuum advance such as the one in my 2dr Chev. They used different distributors. The tach distributor on the 340 horse was designed for high performance, so I don't want to change it as it would ruin the look of the original 327 340 horse even though the inside is now electronic ignition.
I will keep working on the vacuum idea.
Bob
 

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Discussion Starter #15
Your pictures are fine. Try moving your linkage to the top hole on the accelerator pump linkage. See if that helps stop the stalling.
Symptom of a faulty accelerator pump is engine sputtering or stalling. The sputtering is caused by the lack of fuel that is supposed to be provided by the accelerator pump when throttle is rapidly pressed. In more serious cases of accelerator pump failure, rapidly pressing on the gas may cause the engine to stall, again due to the lean condition that can be created when the accelerator pump is not working.
Todd
Moved the linkage Todd...no difference.
Bob
 

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My problem is that when I start it, it idles great, but when I'm on the road and I come to a stop, the engine stalls and dies. I can start it immediately and it will go back to a perfect idle...until the next stop.
Thanks,
Bob

There is a clue in that statement, and I'd focus for a while right there. There's something going on with the fuel inside the carb to me. Might be some sort of slosh that is temporarily starving the idle circuit. I'd suspect float level, but take your word that it was looked at.

I gave up messing with those AFB type carbs long ago. Another enthusiast or expert on those needs to step in here.
 

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"The Corvette carb has only the down draft tube going to a port on the back of the carb"

Bob...It seems to me like this could be the source of a huge vacuum leak....You could try capping it off and see if anything changes. (JMHO)
 

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A few people have mentioned fuel pump pressure.
I did come across this while reading some literature on the 4160.
It does mention stalls:

Avoid extremes in fuel pressure. At IDLE, there should not be any more than 6.0 psi; if the vehicle has
an adjustable fuel pressure regulator, set it to 5.5 psi. With most fuel pumps the minimum fuel
pressure is encountered at high rpm and WOT. Fuel pressure should not drop below 2.0 psi. If it does,
a fuel pump with more capacity may be required. Note that some later model vehicles have mechanical pumps
that will give more than 6.0 psi at idle.

The vehicle will perform well, but may be prone to stalls on quick turns and stops with the clutch disengaged. If this
problem occurs, check the fuel pressure. If it is more than 6.0 psi at IDLE, it should be reduced
through the use of a regulator, such as Edelbrock #8190, or by creating a restricted by-pass bleed to
the fuel return line. Edelbrock Street Fuel Pumps are highly recommended for all Edelbrock Performer
Series carburetor installations.
 

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"The Corvette carb has only the down draft tube going to a port on the back of the carb"

Bob...It seems to me like this could be the source of a huge vacuum leak....You could try capping it off and see if anything changes. (JMHO)
Exactly, Especially since he said he is not using a PCV either. If that is truly set up that way then someone set it up wrong.
 

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One thing that concerns me is that the down tube is connected to the port on the back of the carb identified as being for Pwr Brks.
Are you talking about the road draft tube? It should not connect to anything but the block. Disconnect that line and put a plug/cap on the port on the carb. You have a big vacuum leak.
 
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