. engine stalls when hot - help

[66hcs-conv]

Hi all,

Our '66 (289 - 2bl carb) will stall when it gets hot, and is almost impossible to restart. I have had the carb rebuilt, and the guy puts the rebuilt carb on a test engine and it has the proper air/fuel mixture. I have put new plugs in, use a Petronix II ignition, and a hotter coil.

Friend suggested I put a non metallic spacer between the carb & intake manifold, but I have a PCV connection on the metal spacer now in place. I can't find a nonmetallic spacer that will accommodate the PCV connection.

I have used 85 to 91 octane gas, and try to keep the gas fresh.

I can't figure out why the engine stalls.

Anybody got any ideas as to how I can fix this?

Thanks for your help. Dave

 

[Midnight Special]

...Possible weak fuel pump and/ or vapor lock?

 

[RU_SPCL2]

I'm no expert on this, but from what I have read it sounds like it could be vapor lock as Tim suggested.

You mentioned you try to keep the fuel fresh -- are you possibly running some old winter blend fuel? The high altitude in Colorado and more volatile winter blend fuel could be contributing to the fuel vaporizing in the pump or fuel lines more readily than it normally would at lower altitudes and lower ambient temperatures or with summer blend fuel which has a higher vapor point.

I read one interesting suggestion on how to cure this -- attach wooden clothes pins to the fuel line at various points in the engine compartment to act as a crude heat sink, in effect cooling the fuel temperature down enough to keep it from vaporizing in the delivery system. If this solves the problem, then a permanent fix might involve insulating the fuel lines to keep engine compartment heat from vaporizing the fuel.

 

[g scott]

I had same problems with my B2 a few years ago. It was a bad (new) coil that quit working when it heated up. Are you sure its the carb thats causing the problem? Also if it is the fuel make sure you have no rubber fuel line from fuel pump to carb. Short rubber line from steel line to carb filter ok. Hope you get it figured out. I know how frustrating it can be. gary

 

[66hcs-conv]

Hi all,

Thanks for all the suggestions.

We drove the car to the Steamboat mustang show this past weekend, and it rolls down the road at 65 just fine. I filled the tank a couple of times. But when we slow down and the temp goes up, and then we stop for whatever, then it won't start.

Since we can go 65 mph, and burned at least a tank and 1/2, I've sorta eliminated the fuel and fuel pump. The fuel line is stock metal with the only
rubber being the connection from the line to the filter.

I think I will see if I can find a phenolic (sp?) spacer and drill for the PCV hose fitting.

Thanks, Dave

 

[teamlo]

Had a similar problem with my '68 302 4V running the factory aluminum 1" spacer. Switched to a 1" phenolic spacer, problem solved.

Terry

 

[robert campbell]

Dave,
The attached way below is a GT/CS/HCS link full of good advice. Your car has an overheat or hot start problem when it sits for around 5 to 10 minutes after shutting it off. The engine builds up a lot of heat after shutdown. Normally after I run in to get my six pack of beer..... The carb somewhat boils and introduces alot of gas down inside the intake manifold and causes a hot flooding condition. If you are disciplined and put your foot to the floor, AND DO NOT RELEASE IT UNTIL IT STARTS, you should be able to use short bursts of around 15 sceonds on the starter and it will start and spew black smoke everywhere for about 20 seconds. I do not think a phenolic spacer will provide much relief. I assume you still have an Autolite 2100 2 barrel carb? This is what I would do if it was my car.

1. Drop to a 180 thermostat for the summer. Verify it works with a pan on the stove and a candy thermometer. While you are at it verify the old thermostat as to when it opens. My bet is that this car never sees much winter operation and you can go from the 195 to a 180 no problem. If your radiator is suspect, then you can even drop to 160.

2. Verify that the vacuum advance works. Plug a rubber hose on the vacuum advance with the engine not running and the distributor cap off. Suck on it while you watch the advancer plate move the pertronix around the center of the distro. Very easy to see. While holding a suction (I am very good at this for car work) move you tongue over and plug the line with some suction on it. The advance plate should hold until you remove you tongue and then it will "snap" back. If it holds it is probably fine. If it does not hold the local NAPA has one.

3. Now move the timing marks up on the left side behd the power steering pump with a 15/16 socket and six inch extension on the vibration damper bolt. Clean the marks up real good and get some of your children's sidewalk chalk and rub all over the marks everywhere. Gently take you finger and drag the bulk of the chalk off and bingo, you can see them

4. Get the car up to warm, not hot, with the choke completely released and at a normal slow idle. Unplug the vacuum advance and check you initial timing with a timing light. 6 BTDC degrees is what you car should be set to. I assume it is not a California car with a Thermacter system? I find your car will run allot better at 10 degrees BTDC and even maybe 12. The more you can advance the better mileage, power, and LESS HEAT it will have. You need to ensure you do not "ping" (engine knock under acceleration pulling a mild hill). If you do not have ping get it out to 12 BTDC. You will need to set the curb idle screw back a bit as the engine will idle a bit faster. A quick slide by my house and I will set the idle mixture screws for you! Ok take it back to your guy!

If you take the above 4 steps and the vacuum advance is good, I bet you make a huge difference in your engine operating temp and your hard start when hot goes away!

Do read the link below. It chronicles an engine with your problem.

Rob



http://californiaspecial.com/forums/showthread.php?t=7426&highlight=overheat

 

[66hcs-conv]

Hey Rob,
I have tried all sorts of routines to start the car, and nothing has worked. The only way I can get it started is to take the top off the air cleaner - the big round "pizza pan" - and when it gets some fresh cool air, then it will start. But like you said, I get lots of smoke. I agree, the gas is bubbling over and causing a rich condition.

1. I have the 180 stat it the car now, but will probably drop to the 160.

2. You want me to put my tongue where?! :tongue: I did as you suggested and the vacuum works perfectly. I also checked the vacuum at the small metal tube that goes in the vacuum advance unit (from the carb) and there is lotsa vacuum there.

3 & 4 I did check the timing, and it was right at 6 degrees. I did advance it to 9-11 degrees. It is really hard to tell exactly, 'cause each mark is 3 degrees and the marks are only 1/4 inch apart!

I've got to clean it up from the drive back from Steamboat, and then I will take it for a test & see if there is any improvement.

Thanks for your help, I really appreciate it. Dave

 

[robert campbell]

Dave,
About number two. You should not have any vacuum at hot slow idle at the "tube". If you crack the throttle open just a but, it should jump right up to 15to 20 pounds. This is a "ported" vacuum source and should have no vacuum at idle. As you open the throttle to accelerate or move from a stop sign it feeds vacuum in helps the carb and engine transition form low speed idle circuit to high speed driving circuit. This is also assisted by the acceleration pump and the power valve.

Back to the carb. I never rebuild and Autolite without an old OR new brass float. The black "hard plastic over Styrofoam" floats are impossible to tell if they have been impregnated with gasoline through a small crack. They look ok , but after a few months they saturate with gas and become a "sink" vice a "float". What happens is the float level becomes higher than it should be and also can contribute to "percolating" which is short for gas boil over condition. Very noticeable in the summer. Not so bad in the winter. And they sink very slowly and dry out in the winter when the float bowl dries out. As summer gets into full swing, they sink to the bottom!

If your carb does not have a solid brass float, I highly recommend you get one! Brass floats are fine, or full of gas. Easy to tell!! I have only experienced one sunk brass float in my career of carbs starting in the late 1960's. From Autolites to Rochester's and Carter's, they are a bane to accurate and consistent float level.

Rob

 

[66hcs-conv]

Rob,

The vacuum at the end of the tube is as you described it should be - nothing until the throttle is opened up a little.

And the float is a brass unit, no "sloshing" inside when it is removed and shaken. It floats good, needle & seat are new. Measured the fuel level, and it's right on the gnats heinie.

Thanks, Dave

 

[robert campbell]

Dave,
Ok, the plot thickens. One thing you could try is to lower the float level a bit. It should not affect you performance and could help a bit.

Heat riser: The stock 289 exhaust system does not have a heat riser valve, but its design routes exhaust gas through a center passage in the passenger head under the carb mounting points on the intake manifold to the driver side exhaust manifold. This passage is used to improve performance in the inter and prevent carb icing. It can be blocked with a insert in the intake gasket and a performance intake gasket set automatically blocks it.

We have not talked about your radiator condition:
What size?
How old?
Do you have a radiator shroud? If so we will discuss orientation of the shroud to the fan.
What fan do you have?

The 160 thermo will help some, but if the condition occurs after nice long drive and then some long stop and go, it is heat build up at slow speeds. Answer the above and we will dig further!

Rob
How close is the fan to the radiator core?

 

[66hcs-conv]

Rob,

So, is there a way to block the intake heat passage without removing the intake manifold? I'm not very enthused about removing the intake.

The radiator is a 3 row, 10 years old. I have flushed and replaced the antifreeze every 2 years.

I do have a shroud and the fan is a fixed blade (no flex blade) - 6 blade, and the leading edge of the blades are 1 & 3/8" away from the radiator.

Dave

 

[6t8-390gt]

What is your water temp.? How "fresh" is your engine? I think Robert is on the right path; but you have never indicated what your water temp. is. A fresh engine builds more heat than an older engine. A radiator that worked fine with an older engine may not be flowing sufficiently to cool a fresh rebuilt engine.

 

[robert campbell]

What is your water temp.? How "fresh" is your engine? I think Robert is on the right path; but you have never indicated what your water temp. is. A fresh engine builds more heat than an older engine. A radiator that worked fine with an older engine may not be flowing sufficiently to cool a fresh rebuilt engine.

Dave,
You have to remove the intake manifold. The distance between the core and the fan sound good. The fan blades should be about 30 percent covered by the edge of the shroud with 60 percent uncovered. 50/50 works ok. If the blades are all the way in the (covered) by the shroud, that is not good. I would do the following one at a time in this order. Verify the new and old thermo on the stove.

1. Put in the 160 thermo
2. Sneak it out to 10 degrees BTDC
3. May consider a stainless flex fan
4. Remove the intake and block the exhaust passage.

Drain a gallon or so water out of the radiator and take a visual inspection of the tops of the tubes you can see through the radiator cap. The tubes should be clean and free of any corrosion or "gunk".

Rob

 

[teamlo]

What is your water temp.? How "fresh" is your engine? I think Robert is on the right path; but you have never indicated what your water temp. is. A fresh engine builds more heat than an older engine. A radiator that worked fine with an older engine may not be flowing sufficiently to cool a fresh rebuilt engine.

Well said. Ask me how I know!

 

[66hcs-conv]

I do not have a temp gauge that shows degrees. only the stock inst panel gauge. When going on the hiway at 67-70, the gauge reads right in the middle between C & H. When I stop for a few minutes the gauge will go to the hot side, but doesn't peg past the hot hash mark - the \ on the gauge.

The engine is not "fresh" It has 138K miles and as far as I know it has never had any work done to it.

The tubes on the radiator look good, no gunk or blockage of any sort.

I haven't measured & calculated the % of shroud coverage, but it looks to me the is slightly more sticking out than is covered.

Going to drive it to a show this week end, and we will see what the advance timing and the 160 stat do for it.

THANKS, Dave

 

[robert campbell]

Dave,
I cannot find where you said it was a new or rebuilt motor? If it is new, then it can overpower an old radiator, and for sure will run hot until it gets $2k miles on it.

Rob

 

[robert campbell]

I do not have a temp gauge that shows degrees. only the stock inst panel gauge. When going on the hiway at 67-70, the gauge reads right in the middle between C & H. When I stop for a few minutes the gauge will go to the hot side, but doesn't peg past the hot hash mark - the \ on the gauge.

The engine is not "fresh" It has 138K miles and as far as I know it has never had any work done to it.

The tubes on the radiator look good, no gunk or blockage of any sort.

I haven't measured & calculated the % of shroud coverage, but it looks to me the is slightly more sticking out than is covered.

Going to drive it to a show this week end, and we will see what the advance timing and the 160 stat do for it.


THANKS, Dave

We crossed each other in the internet "tubes". good luck this weekend!!

 

[Midnight Special]

...Alright, so here we go again...
TJ just called me down to his shop where he has a '66 289 with a fat Edelbrock he just finished detailing. He went to deliver & had it quit numerous times after it warmed up for a bit. After much phone discussion & trial, I went down to inspect.

All vacuum lines, plugs, wiring, points, fuel flow, choke funtion etc... normal and fine. 'Started, warmed, went to drive and it sputtered & quit. Wouldn't start again until sitting a while.

Remembering two ocassions on mine and a recent one with Mike, I went & got a $5 condensor and replaced the one in the distributor.

The car fired right up, idle was perfect (after grey smoke from not firing) and she drove around the neighborhood flawlessly! We kept stopping and re-starting along the way with no problems!

Now I'll leave it to you motorheads to try and explain why...but instead of taking your (proven) engine all apart - why not first give it a try!

 

[robert campbell]

...Alright, so here we go again...
TJ just called me down to his shop where he has a '66 289 with a fat Edelbrock he just finished detailing. He went to deliver & had it quit numerous times after it warmed up for a bit. After much phone discussion & trial, I went down to inspect.

All vacuum lines, plugs, wiring, points, fuel flow, choke funtion etc... normal and fine. 'Started, warmed, went to drive and it sputtered & quit. Wouldn't start again until sitting a while.

Remembering two ocassions on mine and a recent one with Mike, I went & got a $5 condensor and replaced the one in the distributor.

The car fired right up, idle was perfect (after grey smoke from not firing) and she drove around the neighborhood flawlessly! We kept stopping and re-starting along the way with no problems!

Now I'll leave it to you motorheads to try and explain why...but instead of taking your (proven) engine all apart - why not first give it a try!

Tim,
So now we know why they always said to replace the condenser when you replace the points!!! Always a cheap try!

Rob