jalexquijano

Does anyone know who fabricates a custom heat shield for a 1972 240z covering the float chambers and each and every part between the manifold and the SU Round Top Carbs?

THis guy is making his own but does not look very profesional. I want to eliminate the vapor lock that causes my car idle to become rough and eventually leads to stalling on traffic.


I have only seen for mikuni triple carbs but not for stock SU carbs. Anyone?

PCressey

The stock heat shield doesn't work? I wrapped my headers (without a heat shield) and haven't had any problems at all here in SoCal in 90 degree weather.

I vaguely remember looking for a new heat shield last year, but didn't have any success... hence the wrap.

jalexquijano

The sympom i have is the following:

Car runs great when cool and during non stop situations. However, when car is left at idle on traffic jams or long lasting traffic lights the idle becomes rough and after a while the idle drops from 1000 to 400 rpm and rises back. THis is really unconfortable when driving. I still have the original stock fuel rail but wrapped.

PCressey

Here are a few thoughts:

1. Have you checked the fuel pressure? Lower the fuel pressure, the greater the chance of vapor lock. Since it only happens at idle, maybe you are a pound low, and that is just enough.

2. Is the fuel line from the tank up through the firewall and into the fuel rail away from the radiator, engine, or any other heat source?

3. Have you used a temp gun to check what the temps are at each section of the fuel delivery system? Narrow it down from there? Fuel line, fuel rail, float bowl, etc.