I just finished my first engine rebuild on a 1965 Ford 390. I got it started tonight and it pretty much fired right up. I was able to get it up to 2k RPMS for about 10 minutes to try and get the cam to break-in.

I noticed it was starting to get a little hot after I looked at the temperature gauge and it was about 3/4 of the way up. I shut it down and cracked the reservoir cap to try and let the pressure off. It blew out the overfill hose and onto the floor...no biggie but seemed like there was a good amount of pressure.

The oil pressure gauge only got up to about a 1/4 of the way. I would expect it to hang around the middle between L and H but it was only about 1/4 of the way. Oil is at the right level after I checked the dip stick.

After reading online there are a few things it looks like I should check I just don't know where to start.

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I guess I just don't know where to start and what to do first. I don't want to make sure I don't damage anything since this is my first rebuild. I am glad it fired right up but I dont want to damage anything.

Thanks in advance for your help.

 

I got a reman 390 years ago from a large company that remans lots of different engines. It ran fine once it got past the break in stage. For the first few hundred miles it would get scalding hot. My newish engine never went through that scalding hot break in stage but it was built by a guy who specializes in FE's.

Once you check it over again, you might mist water through the radiator to keep the temp reasonable as you break in the cam. Then drive it and keep an eye on it.

 

Here are a few answers to your questions;

1. drilling two or three holes in your thermostat is done so that on startup, and the thermostat is shut, air can bypass the thermostat. An air pocket can build up behind the thermostat so coolant will not touch the thermostat to open it up.

2. Take off the radiator cap, before starting the engine and while engine is cold. When your thermostat opens up, you will see coolant moving under the radiator cap housing.

3. Does your radiator have a fan shroud? Does the temperature go down while driving at normal speeds?

4. At what temperature does your water thermostat open? Does it open fully?

5. You can check your thermostat by putting it in a pan of water on your stove and place a thermometer in the water and watch to see at what temperature the thermostat opens. 180 degrees is a normal average for most FE's.

Check the obvious things first.

 

Thanks for the help, I will check a few things tonight.

I am going to get a timing light after work to check the timing. I was reading online that you should just get the car running for the break in and then mess with the timing? Either way it could be why its getting hot.

I ordered a new rad last night, $160 online and it has the trans ports too.

Was anyone able to verify that water pump I bought is the right direction?

 

I've never heard of an FE with reverse rotating water pumps....

With a new build, they always run a little hotter until broken in.
Two biggest reasons for running really hot on a new build are retarded timing, and a small vacuum leak which causes a lean condition.

For cam break in, I run the timing pretty far advanced so the engine stays cool. There is no load on it, so it doesn't matter all that much.
I wouldn't worry about cooling system problems until you have the tune figured out, and get real gauges.

 

Reverse rotation water pumps are usually a marine thing, and while there was (a long time ago) marine-version FEs, I think those days are long gone. The other reason a reverse-rotation water pump would be used is with a serpentine belt, like for the small-blocks, but again, not on FEs.

I would suspect the radiator first, and if you don't have a fan shroud, it WILL run a bit warmer when the vehicle is not moving. Also, like others have already said, a newly rebuilt engine will run hotter than "normal" for a little while as it breaks in. The friction of the pistons/rings in the bore will certainly make a big difference.

As for checking if the head gaskets are in correctly, get one of those "point and shoot" thermometers. If the back of the block and heads are a LOT hotter than the front, then the gaskets are reversed.

 

OK, ordered the infrared thermometer I will check that when it gets in. I do not have a fan shroud on the car yet since I'm waiting to get everything done before i scratch it up. It shouldn't make a difference though since i have a large floor fan blowing directly on the radiator.

 

With the digital thermometer, check the temp of the top radiator hose, or even better, the thermostat housing.

The old dash gauges can be very inaccurate as well. Did you put a new temperature sensor in the intake for the rebuild? That alone could be a cause of the difference in perceived temperature

Get some readings and get back to us

 

I did put a new one in, i think i got that on rock auto. ill check it out tonight.

 

Ooo, does this sound very, very familiar. I know a new radiator and fan shroud didn't work. Even had two temp sensors with one in the intake and one in the thermostat housing. Both read high.

 

After letting it sit overnight i got the air pocket out, car took another half gallon of coolant. Let it run at 2k for another 15 min and it held at what i would consider a reasonable level for sitting still with a fan on it. I let it idle down and it seemed ok. Ill post back when i get the hood on it and take it around the block.

 

To check if head gaskets are on correctly, you can also take the water pump off and feel the head gasket in the coolant jacket.

 

I would expect it to take right at 5 gallons... assuming you have stock radiator and no cooling add-ons. That should give you 2-3 inches or so of expansion room under the radiator cap.