Need some help. A Stock 241 Baby Hemi, only mods are a 4V aluminum intake and duel exhaust. Intake has a 385cfm Carter 4V and runs great until the temp gauge reads 160F then the engine falls apart . The intake gets VERY HOT as well as the carb. If you cool it off with water it runs fine again until it heats back up. I blocked off the heat risers and it still does the same thing. Any Ideas? To much timing? Not enough fuel?
How did you block the risers? Cast iron plugs work good. Like these http://www.summitracing.com/parts/EDL-2733/ They dont make these for a hemi, but you might be able to shape these ones down to fit. I have these in my Olds 455. They take some grinding to make them fit - need to be a snug fit into the head. I'm going to do the same thing to my 331 Hemi
I made a set up on the mill with a threaded center so I can slide hammer them out if I need to remove them. But it made no difference in the manifold heat with the plugs in or out.
160 is not very hot. The engine should run fine up to 220 if the cooling system is working. The question appears to be why is the intake apparently getting so hot as to disturb the carb. What exactly is meant by 'falls apart' ? Give us a little more detail. .
I have a 241 Dodge Hemi and I have no issues with my intake and carbs..I don't believe the cross over is the problem..Exhaust is getting there somehow.. Duane.
If is defiantly boiling the fuel in the carb, "falling apart" as in stumbling and will have trouble running. As soon as you cool the intake down it runs fine until it gets hot again. The heater hoses are also a lot cooler than the intake so I have no doubt that the Autometer temp gauge is correct in the 160F temp. The car is not running a thermostat at this time but it did the same thing when it was running a 180 thermostat in it. The carb is a 385 CFM unit and it should be plenty of flow for a 241. Will pull the plugs tonight to check the burn on them.
Timing or carb can't make the intake run hot. It has to be exhaust heat. Is there a heat riser valve in one exhaust manifold?
There is no heat riser valve installed. There is nothing hot about the engine except for the intake. I have never seen anything like it.
Are you sure that you blocked the exhaust heat passages? The other thing I can thing of is cam timing is way off. What intake is it?