Still too hot.

[Brass]

Hi all,

Once again I need to turn to all the good folks here for help.  I recently switched from an aluminum reproduction of the stock intake to an Edelbrock CH4B on my 440.  It now seems to be generating an inordinate amount of heat, and the shop I have it with is telling me that the heat riser valve is missing.  The car over-heated and it also appears to be heating the fuel, making it hard to start and causing vapor lock.  Timing is good and the carb has been tuned using an o2 sensor.

This seems to be a common problem on this forum.  The links below reference a Felpro intake gasket that will block the heat crossovers and a 1/8 inch "insulating" (phenolic) carb spacer.  Does anyone have part numbers?  Also, would it be worthwhile to use a vapor separator?

http://www.dodgecharger.com/forum/index.php/topic,52284.0.html


http://www.dodgecharger.com/forum/index.php/topic,57864.0.html

Many thanks!

[Brass]

Doh!  Ron provided the part number for the intake gasket in his post.  (At work and read a little too quickly.)  Think I still need a number for a good carb spacer though....  I am using a Holley 4778.

[TylerCharger69]

I blocked off the heat passages in the intake manifold.....problem solved!!

[Brass]

Okay - I have the Fel-pro intake gasket and a 1/2" insulating spacer under the carb.  Its better but its still too hot.  The fuel line has even been routed away from the exhaust.  The Needle goes right up to 12:00 and the car tries to cut out whenever I lay into the throttle a little.

The radiator, water pump, and thermostat are all good.  It was tuned using an O2 sensor so I don't think that is the problem.  (Though it does smell much richer now.)  The only thing I can think of is that the line leading into the carb is metal, which may be conducting heat from the intake manifold.  I'm willing to change that but it seems (or should be) unnecessary.

Otherwise the car seems to run good and sounds awesome.  (Thank you, Ron!)  I think I found the low-end response I was looking for, and am anxious to get a real sense of the car.  But this quirk is perturbing me to no end.

Any thoughts?  Thanks, all.

[1969chargerrtse]

The vapor separator helped my car a little.  It routes the fuel back to the tank rather than sitting there in the hot engine bay.  Any chance there's a small leak into the water chamber from a small leaking head gasket?  The car will run fine but it pumps hot exhaust into the water chamber.

[elacruze]

What is your coolant temperature?
You say it's overheating but I'm reading into your posts that you have a vapor lock problem not an engine coolant problem. Is that correct? The change of manifold should not affect coolant temperature if you didn't change the timing/compression or lean out the motor.

[Brass]

Yes I think it is a vapor lock issue being caused by the heat from the engine.  The vapor separator is a good idea and I'm willing to try that.  But today I discovered that the heater core appears to be going out.  (The passenger side carpet was soaked.)  Could the bad heater core cause the high engine temps, which in turn lead to vapor lock?

[elacruze]

If you have had low engine coolant, you may have air trapped in the system which can cause heat buildup in those areas. Re-route the heater hose back to it's source bypassing the core, and check again. You should do a system pressure check, and check the radiator cap for proper function also. I've seen many caps, new ones, where the vacuum valve has a broken or no spring and droops open preventing pressure from building in the system.
I had a CH4B on my 440 and loved it, never had any heat issues even with 11:1 compression and iron heads.
Need some data-

Max. coolant temp
static compression
idle and max. ignition timing

[firefighter3931]

Yes I think it is a vapor lock issue being caused by the heat from the engine.  The vapor separator is a good idea and I'm willing to try that.  But today I discovered that the heater core appears to be going out.  (The passenger side carpet was soaked.)  Could the bad heater core cause the high engine temps, which in turn lead to vapor lock?

A cooling system that won't hold pressure will increase engine temps significantly. The increased running temperature is creating the vapor lock most likely. Bypass the heater core as suggested above and see what happens. 

Glad to hear the new intake manifold and carb is working for you 



Ron