Hard HOT starting

-
C

charger426

Well-Known Member
Joined
May 5, 2014
Messages
1,071
Reaction score
320
Location
MoparLand
Just put a 440 in the dart and I'm running into a problem where the car doesn't want to start after its warm and has sat about 30-60 min. Stone cold will start after two pumps and two cranks, turn it off and right back on no problem its that in-between time thats the problem. To get it to start I have to push the peddle all the way to the floor like its flooded and after keeping it running around 2500 for 10 seconds it clears up and idles fine.

From looking around it sounds like this is a problem that people are quick to blame on gas but there has to be something I can do.

Specs:
Stock 78 truck bottom
Trick flow heads
Hughes Whiplash cam
Edelbrock Performer RPM intak
Demon 850
MSD 6AL-2
MSD Blaster SS Coil
3/8 fuel line, 3/8 sending unit, and fuel filter between carter mechanical fuel pump and carb. All rubber line.

Thinking about adding a Holley insulted spacer to help keep some heat off the carb and fuel bowls...
 
Modern alcoholized, boiling, vapor lock. Parked hot, fuel boils, forces "over the top," and floods the engine and or empties the carb.

"What helped" alot on my 67 was a rear mount electric pump, a thick carb insulator, and a home / DIY return system. Used a Wix 33040/ 33041 filter which has a built in return orifice

You can get various sleeve / insulated tubing from Summit etc.
 
I ordered a holley heat shield and some fuel line insulation. Should be here tomorrow so I'll see how it goes.
 
This is an easy diagnoses if it's boiling the fuel. Next time you shut it off hot, just pop the air filter house off, and hang around looking for smoke coming out of the airhorn. You can also lean over the top and look for fuel dripage down into the bores.
But my money is on a messed up T-port sync.

And here's why; I run 87E10, and have since it came to town in about 1999. I run my engine hotter than most, with a water temp of 205*F.I run aluminum heads, a 230* cam,uncoated TTIs, and 10.7Scr. I run a factory 26" A/C rad with a thermal clutch-fan.I run a mechanical pump and 3/8 steel line all the way(no rubber on the pressure side); the Big steel filter is on the suction side, at the back.No fancy ignition system either, just the large Accell Super Coil, and idle timing is just 14*. Even on a cool day, it is hot as Hades under that hood. The only help the old Holley 750DP has is the AG manifold.And in part throttle use, that's as good as no help at all.
Bottom line is it never boils the fuel, no matter how hard I run it.I just touch the key and it jumps to life.

But if your T-port sync is out, you will have problems....................
As also you will if the valves are not fully closing.
 
Where is the initial timing set?
 
Put on an electric fuel pump and shut it off and let the carbs run dry before turning off the ignition so when you restart it the bowls will have nice cool fuel in them
 
With the key on, the voltage at the coil is somewhere around 7 volts (Start 1). Make sure you have a full 12 volts at the coil when the motor is cranking (Start 2).

A decade or two ago, I had mine hooked up wrong and it didn't bypass the ballast resistor to give a full 12 volts when cranking. The truck was always really hard to start when warm until I fixed that.

I live in a moderate climate. Blocking the heat crossover in the intake, adding a 1 inch phenolic spacer under the carb, adding a return line and insulating my fuel line around the engine help even more. It also improved the drivability and performance. I used a manual choke on really cold days.
 
GEO said:
Put on an electric fuel pump and shut it off and let the carbs run dry before turning off the ignition so when you restart it the bowls will have nice cool fuel in them
Click to expand...


This is what works

Or put a regulator on a return after the carb. This stops the flooding issue caused by vapors holding the fneedle and seat open. Most all cars with out a return system will do this. It is common with ethanol. Methanol is even worse . Fuel injection is the way to go I am switching my duster to port injection when boosted. Steve
 
I had a similar problem with the 440 in my Dart. It would also vapor lock from time to time. I believe your on the right track with the heat shield. That's what cured mine. What temp does the motor run?
 
GEO said:
Put on an electric fuel pump and shut it off and let the carbs run dry before turning off the ignition so when you restart it the bowls will have nice cool fuel in them
Click to expand...

jbc426 said:
bypass the ballast resistor to give a full 12 volts when cranking.

I live in a moderate climate. Blocking the heat crossover in the intake, adding a 1 inch phenolic spacer under the carb, adding a return line and insulating my fuel line around the engine help even more. It also improved the drivability and performance. I used a manual choke on really cold days.
Click to expand...

All of this /\ /\ /\

ANd the best spacer which will make you more power is an HVH super sucker 1".
 
340doc said:
I had a similar problem with the 440 in my Dart. It would also vapor lock from time to time. I believe your on the right track with the heat shield. That's what cured mine. What temp does the motor run?
Click to expand...

Well the fans kick on at 180 with a 180 thermostat. Using the factory gauge set so right inside the main section by the C....I know thats not a number but thats What I have to work with.
 
Sounds very much like the carb is getting hot and boiling over. A good 4 hole phenolic spacer should improve performance and solve your problem if you have room for one. Depending on which Carter pump you have you may need a regulator and or a vapor return line. A hot carb with residual line pressure of more that 6.5 psi is asking for what you are experiencing. What is your fuel pressure running and at shut down?
 
mguner said:
Sounds very much like the carb is getting hot and boiling over. A good 4 hole phenolic spacer should improve performance and solve your problem if you have room for one. Depending on which Carter pump you have you may need a regulator and or a vapor return line. A hot carb with residual line pressure of more that 6.5 psi is asking for what you are experiencing. What is your fuel pressure running and at shut down?
Click to expand...

With my break in carb around 6-7 running. Don't have an inline gauge on this carb but don't see why that would change. Being a flat hood I really dont have a bunch of room. I went with the Holley heat shield because it was only 1/4" thick but covers the fuel bowls....hoping that helps.
 
I hear you, well I guess see what happens when you get your new stuff installed. If you still have the problem you might think about temporarily installing a good temp gauge to get some numbers. Also make sure you have enough initial timing. Do you have your timing info? Initial and total?
 
340doc said:
I hear you, well I guess see what happens when you get your new stuff installed. If you still have the problem you might think about temporarily installing a good temp gauge to get some numbers. Also make sure you have enough initial timing. Do you have your timing info? Initial and total?
Click to expand...

Don't know the timing numbers. Tried to set the timing with a light but I'm guessing the mark has moved or was never marked right. I set it the digital tac on my timing light to where I got the most RPMs out of the motor, re adjusted the carb and haven't had a chance to go back and play with it anymore. I know thats not the best way to do it but Uncle Sam is shipping me out and I'm just trying to get this safely drivable so my mom can take it out to show nights and keep it moving while I'm gone.
 
charger426 said:
Don't know the timing numbers. Tried to set the timing with a light but I'm guessing the mark has moved or was never marked right. I set it the digital tac on my timing light to where I got the most RPMs out of the motor, re adjusted the carb and haven't had a chance to go back and play with it anymore. I know thats not the best way to do it but Uncle Sam is shipping me out and I'm just trying to get this safely drivable so my mom can take it out to show nights and keep it moving while I'm gone.
Click to expand...

Sounds like you are using a dial back timing light?

Just an FYI you cannot use a dial back on an MSD. You need a straight timing light.
 
Doesn't sound like a hard crank, more like a clear out the fuel thing...
 
mguner said:
Doesn't sound like a hard crank, more like a clear out the fuel thing...
Click to expand...

Agreed. Sometimes the first crank is hard, like when I first hit the key but after that it cranks fine. Only way to get it to fire is to go full throttle (like a flooded car). So the idea that the fuel thats in the bowls and line heat up and drip into the carb sounds logical in this case.
 
roccodart440 said:
Sounds like you are using a dial back timing light?

Just an FYI you cannot use a dial back on an MSD. You need a straight timing light.
Click to expand...

Not sure what you mean? I didn't know there were different lights. Is there a way to tell what kind I have? Its a digital display that lets me adjust for advance and has a RPM read out.
 
charger426 said:
... lets me adjust for advance ...
Click to expand...

That's what makes it a dial back. Get the simple/cheap/crappy version that doesn't do that ;)

disclaimer: I don't think all non-dial back timing lights are crap. But the parts store guy will give you crap for not buying the one with the most whistles.
 
Ahhh see what your talking about now. Just get an inductive kind...never knew that was a thing with MSDs. Looks like Amazon has an inductive like for $35.
 
mguner said:
Doesn't sound like a hard crank, more like a clear out the fuel thing...
Click to expand...

Which is why I asked where initial timing is. If it is retarded, cranking time will increase dramatically.
 
You must log in or register to reply here.
-

Back
Top