1990 - 560SEC---- I am sick of my Old (Worn Out) fuel injection stuff and am removing it all and fabricating parts to put a 600 CFM Holley carburetor on it and removing the 2 high PSI fuel pumps and installing 1 low pressure fuel pump, My 560SEC is a beautiful and Good car, But it has 224,700 miles and there is (Many) problems with the complete fuel system, I have had (Many) people say this can't be done using the stock intake manifold because it is designed to be just a (Dry) air intake, I say Bull-****, Just watch me !

Attached Thumbnails

 

Carbs have been applied to the M117 in the past.
An R107 was run in Trans-Am using four Weber IDAs.

Or you could convert to MegaSquirt using Bosch injectors from a '90's era Ford product. Plenty of info out there regarding the installation.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

You are very right, But that is expensive and I am a fabricator and welder, I like to make everything myself, Its fun for me and I like figuring out the problems as I go.

When you do a carb install, directing heat to the area below the carb is a must. Accomplish this by running a tube from one exhaust manifold to the area below the carb to the other ex manifold or run heater water flow through this area.

If the carb is too cold, you will have major running problems in colder weather ( like 50* F and high humidity. )

You may get poor mixture distribution running a carb on a FI manifold. And, carbed V8 manifolds are usually dual plane where 2 cyl from each bank are connected to 1/2 of the carb. This helps low speed performance.

Check the intake port spacing, you may be able to adapt a USA V8 intake will less fuss than making something from scratch.

97 SL320, You make a very good point, Very good information, Thank you very much.

I have a 1990 - 560SEC, I put a 600 CFM Holley carburetor on it and removed the 2 high PSI fuel pumps and installed 1 low pressure fuel pump, I have the kept the stock (Dry) intake manifold and made a adapter/Plenum and put the Holley on it.

97 SL320, Your Comment was.

When you do a carb install, directing heat to the area below the carb is a must. Accomplish this by running a tube from one exhaust manifold to the area below the carb to the other ex manifold or run heater water flow through this area.
The car runs super strong and has amazing power now, But like you said, It won't take the throttle until completely warmed up, Should I run a 1/2" exhaust pipe (through) the carb adapter/Plenum or just weld it onto the outside so it will transfer heat ? I am afraid if it goes (through) the carb adapter/Plenum it could cause a fire ? when first shut off ? What do you suggest I do, Thank you so much for your help.

Attached Thumbnails

     

Running the tubes as shown would keep the carb from freezing in cool damp weather but would not do much for cold engine fuel evaporation.

Have a look at a carburetor V6 or V8 engine, there is an exhaust cross over passage from head to head under the floor of the intake manifold, this is where you need to direct heat. ( when I said "bottom of carb area" I should have been more clear with " floor of intake manifold". )

Also have a look at a air cooled VW intake, they have the steel exhaust tube / steel intake tube cast together with aluminum.. There isn't enough heat there to catch things on fire however, if you run an exhaust tube you may need to insulate it so things around it don't catch fire.

Does this engine use an EGR valve? That would be a good source for an exhaust supply. Does this car use an AIR pump? That could be a good place to return the exhaust.

If you are in a warmish climate, you might get away with a heat stove on an exhaust manifold, flapper valve and vacuum thermostat. Look at any car from the early 70's for a diagram of a heated air intake system. This coupled with hot water under the floor of the intake manifold might be enough.

All of this will take some experimentation.

Thank you so much for your help, it did have an EGR valve and an air pump but I removed both items, I also removed all of the catalytic converters and build a 3 inch exhaust system with a stainless muffler with a 4-inch outlet, it sounds amazing and runs super strong hard and good when warmed up, I drove it all one day on a 75 mile trip and fine and works great, but would not take the throttle at all on startup cold with only idol for about the first 5 minutes, I think I will try running the exhaust from where the EGR valve used to be and drill and tap a hole in the other exhaust manifold for a return and enclosed my air cleaner and make a heat stove for it like you suggested that maybe to get things just right maybe, I like the idea of the exhaust because it will get hot immediately instead of having to wait for the water temperature to come up, it was only 35 degrees here in Illinois the day drove it 75 miles, I am only planning on driving this car in the summer anyway so it should workout fine, again thank you so much for your help

You are welcome. Try a heat stove at first since it is easy to make and you need one anyway. This might be enough.

To clarify my exhaust fire post. There isn't enough heat under the carb floor for the exhaust passage to catch fuel on fire, but external tubes you run might melt things near by if not insulated. For handy flex tubing, look at the EGR tube in a 99 ish GM 4.3 V6 ( and probably the 5.0 5.7 )

So how is this car running now that you've had almost a whole year to work all the bugs out and fine tune it?

__________________
2007 Dodge Ram 3500 Cummins Turbo Diesel 4x4
1994 GMC S-15 pickup 4.3 5MT
1985 300 SD
1978 300 CD
1962 220-S Fintail - awaiting restoration

This sounds interesting, can we see?

__________________
With best regards

Al