Guys, I really need help please. I rebuilt a 383 TPI engine that was originally in the car when I bought it. Before I rebuilt it, the previous owner didn't set the lash correctly and he just installed new lifters on an old cam! So it wiped out 7 lobes. Anyway, it had an overheating problem before, but went away a week before builtup. I started it tonight, reved it up and down between 2,000 and 4,000 RPM, per machinests request, and it went up to 260 degrees in 7 minutes! I turned it off, left the fan on and checked the fluid level after it quit boiling. I was fine on fluid, but the upper radiator hose could be squeezed together. So that's one thing I found. I let it cool down, rechecked the level of fluid, and started it up again, and the same thing happened. This time I could see the exhaust manifolds glowing. I though Oh sh-t, so once again I let it cool down, then thought to check the fuel pressure. It had an adjustable regulator on it and after I put the gauge on it it read 31 to 32 PSI. So I unscrewed it all the way, by this time I have some gas trickling out the top, and it only read 35 psi. I decided to call it a night and get on the web to get all of your opinions. Could the diaphram be bad in the regulator, causing the engine to lean out and overheat so bad? I checked all of the vaccume lines and they seem ok, and the timing is set.

Any comments or suggestions would be a great help.

 

you might want to try jacking the nose of the car as high in the air as possible(just the front of the car)
take the radiator cap off and start the car if you can see bubbles come out of the filler neck you had air pockets in the system

kinda like vapor lock
that is why you could squeeze the hose and it felt like it had no pressure
let me know how it turns out
jimbo

 

Thanks for the reply, I went home last night and changed the regulator and dialed it in at 45 psi with the vacuume gauge disconnected. Long story short, it was too much pressure, so I set it at 39 psi and the car ran great and the temp doesn't go above 170 degrees.

 

good
i hope everything works out well!

 

Also you might want to try spraying the radiator with a hose as best you can scince the car isn't moving. And a fan bloing air in front of the airdam.

 

check for leafs between the evaporator core and the radiator, you would be amazed at the amount of crap in there.