cold blooded 390 FE motor

[Bob Shafto]

My 390 '66 Galaxie 500 needs 30-45 seconds or more of fast idle time before I can put in gear (auto trans) without it stalling out.  Is this normal for these engines or is there something I can do about it?

[ddavidv]

My experience with a '65 F100 was pretty similar. They are giant lumps of cast iron. It takes them awhile to get warm. 

My truck had a manual choke which may be better at getting underway sooner as I controlled when it would pull off, vs an auto choke.

[Bob Shafto]

Thanks, nice to know I'm not the only one with this issue.

[Bloo]

I saw this thread a few days ago, and have been thinking about it ever since. my dad bought a 70 Mercury with a 390 around 1985-86, daily drove it until 2000, and I was maintaining it the whole time. It did not have any cold blooded issue that I recall. Sometime in the 2010s a load of bad gas glued the valves stems and bent a bunch of pushrods. Not realizing what had happened, I was trying to "tune" it enough to get it into the yard and screwed up all the choke and fast idle adjustments. It never got more than a quickie fix to the carb after the engine was repaired, and it isn't ideal now but I still wouldn't call it cold blooded. I'm pretty sure a proper setup would take care of it. I'm struggling to think what might be going on with your 390.

 

I don't recall if these have a heat riser. They do have carburetor heat via an exhaust passage through the intake manifold, and lack of carb heat will really screw up driveability until the engine is fully hot. On some engines the passage can get plugged. I don't recall if the 390 is prone to this or not. It might need the intake manifold taken off and the passage cleaned out.

 

A 390 has two steel lines made of Bundyflex for the choke stove. One takes clean air from the top of the carb at the air filter over to the choke stove at the rear of the right exhaust manifold, and the other one sends hot air from the choke stove back across to the choke housing on the carb. A tiny vacuum bleed inside the choke housing keeps the air moving. The hot line has a fiberglass sleeve on it for insulation. These lines have a tendency to rust out and break. I have also seen the cover on the choke stove on the right manifold break. It might be missing. It's cast iron, but a piece of flat steel bar with a bolt hole drilled in it will do if it is missing. The air lines themselves I suspect are probably available thanks to the Mustang restoration aftermarket. If not, it is possible to make them by bending brake tubing and brazing on little rings of wire and adapter sleeves of different sized brake tubing to make the ends fit properly. Napa also used to, and might still stock a universal kit to make a replacement from aluminum tubing. It isn't exactly pretty but it works.

 

Edited yesterday at 12:30 AM by Bloo (see edit history)