400BB hard to start when hot

[evilmopar]

Hi all!
I have a issiue with my 411 bigblock engine.. it won´t start when the engine is hot.. or it´s very hard to start. When cold it fires right up in 5sec. And when i drive it hot i can turn it off and start again within like 5min but if i let it sit for 15min it´s terrible hard to start. I have a Edelbrock performer RPM intake, a quickfuel 650 carb. MSD 6AL2 ignition with probillet distritutor. I´ve isolated the fuel lines from preassure regulator to carb but had no effect. I have a 2" alu spacer under carb but it doesn´t help either.. Anyone having a good solution?

 

[5.7 hemi]

That aluminum spacer isn't helping at all! You need a phenolic spacer, this wont conduct the heat like the aluminum. I suspect your fuel is bowling. Ditch the aluminum spacer!!

 

[evilmopar]

I had a "wooden" one before but it cracked and got bent so i swiched to one in aluminum but i had also had the problem with the "wooden" one...


This i´ve tried but it cracked between the layers and leaked.

 

[SlinktRR]

I had a "wooden" one before but it cracked and got bent so i swiched to one in aluminum but i had also had the problem with the "wooden" one...

View attachment 262375
This i´ve tried but it cracked between the layers and leaked.

Could be a heat soaked starter (especially with headers) or too rich of a mixture. Hold the pedal 1/2 way to wide open and then crank. Does the starter sound like its struggling when you try starting?

 

[evilmopar]

No the starter turns the engine just as fast as when the engine is cold. I run A/F 14,8 on idle so the engine is not rich when i turn it off...

 

[SlinktRR]

No the starter turns the engine just as fast as when the engine is cold. I run A/F 14,8 on idle so the engine is not rich when i turn it off...

Yep I mean rich after you key off and the car sits in it's own heat for awhile. What I get sometimes when it's very hot is the car will act flooded after it has been off for 15+ mins, I have to open the throttle to lean out the mixture enough to start. Edelbrock carbs have this happen so much with ethanol gas that there is a tech bulletin on it, they say that the fuel boils and gets into the intake making for a flooded condition. The only way I can seem to prevent it is to lean the jetting when summer comes. If I go too far the car is down on power, so I just live with opening the throttle half to full open to get it started on occasion.

 

[67 coronet]

the newer fuels evaporate much faster and cause a vapor dense air mix when the car sits in its own heat for a while.you either need to vent the eng bay somehow(louvers or such)or try a heat shield with multiple layers.link....http://www.summitracing.com/parts/mrg-3710

 

[dieseldazzle]

Is this a blow thru setup?? I see your signature says turbo car.

 

[evilmopar]

Yep it´s a blow thru setup, but the turbo is remote mounted under the car behind the rearaxel so there is no heat from turbo that will heat up the engine compartment. It´s a quickfuel 650 carb and it works flawless otherwise.

 

[Dennis H]

Characteristic. Add ethanol and symptoms get much worse. Ethanol boils at 173 or so so it empties the carb even when engine is running normal temperature. Phenolic Carb spacer, wrap and move fuel lines.

 

[coloradodave]

Do they even use ethanol in Sweden? I would try a 1" thick phenolic spacer and, as has been said, insulate all the fuel lines in the engine compartment, especially where they pass close to any exhaust components. Have you tried removing the hood to see if it reacts any differently? In a couple of my old cars I made aluminum spacers to raise the back of the hood at the rear to vent the engine compartment in the summer time.
Another question. When it does eventually start, does it puke black smoke for a while? Have you pulled a plug or two after it sits and you spin it over a few times to check for fuel soaked plugs?

 

[evilmopar]

Do they even use ethanol in Sweden? I would try a 1" thick phenolic spacer and, as has been said, insulate all the fuel lines in the engine compartment, especially where they pass close to any exhaust components. Have you tried removing the hood to see if it reacts any differently? In a couple of my old cars I made aluminum spacers to raise the back of the hood at the rear to vent the engine compartment in the summer time.
Another question. When it does eventually start, does it puke black smoke for a while? Have you pulled a plug or two after it sits and you spin it over a few times to check for fuel soaked plugs?

Yes we do use ethanol in our gasoline but we have 95, 98 and 99 octane and then we have a E85 ethanol. I usually run on 98 but the problem is the same regarding wich fuel i use. But i think the there is ethanol in all our fuel.. but i don't know how much...

I have the hood opened a bit in the rear to vent heat but it doesn't. Yes it pukes black smoke when it starts so i think it gets soaked while sitting.. but how do i get around that problem?

 

[67 coronet]

try removing the hood and do a normal drive with it to see if that solves the problem.at least then you will know if better venting will help.

 

[evilmopar]

I did some testing today.. run the car on 95 unleaded fuel and drove it with hood closed, went in to my garage after some test n tune and left the car with the hood open and after aprox 15min the fuel bowls was empty. I have now a phenolic (spell) spacer under the carb but it doesn' seem to help. The engine starts with part throttle but runs very rich at start up. So back on square one.

- - - Updated - - -

My setup

 

[Dennis H]

Check the temps in a few places after full warm up with a digital laser temp gauge. Let us know. Hot start with half throttle not bad. See you have your lines wrapped.

 

[evilmopar]

I'll see if i can bring the thermalcamera from work tomorrow and take some pics.

 

[dave5237]

Hi guys. I am all to familiar with this. You all know I had the same problem and started a whole thread on this. I have to say after I have installed my electric fuel pumpI have solved the issue. The fuel was boiling off. Now when the car sits I turn the key and the bowls fill back up. Fires right up.Still boiled off when I had the phoenalic spacer. I agree with you guys. Good luck!

 

[Dennis H]

I've had an electric pump the whole time. I will try letting it run in advance for 20 or more seconds the next time I have a good heat-soak going. How long do you run the pump before spinning it?

 

[dave5237]

It seems the line is full and I can hear the change in flow after 10sec. with the key on ( i did put a switch on it with a in line fuse when i did my set up, acts like a theft deterrent) back to the tank. Couple pumps and put my foot to the floor and she fires right up.

 

[evilmopar]

I have a electric fuelpump but the problem i think is that the fuel that boils of the fuelbowls finds it´s way in to the engine and soaks the plugs and so on thats the big problem i think. filling the fuelbowls with the electric fuel pump just takes a second or two. Iwould like to get around that problem so it won´t boil of the fuel. It will save the life of the starter i already burn´t one ministarter and don´t want to do that again, it´s a pain in th a... to change the starter with my headders on...