Hi all,

I'm really a dodge guy, but I've been working on a '74 ford dumptruck for a buddy of mine. Here's the scenario: The truck supposedly came with a 361, whereabouts unknown now. I'm told it has a 391 in it presently.

It popped a headgasket and made a milkshake in the crankcase, so my buddy pulled the heads and sent them off to be milled flat and checked for cracks. I came into the picture after he got the heads back-I put them back on, and reassembled the rest of the top end of the engine. It now runs fine, except that it overheats after running for a while. I'm beginning to think that it ran hot in the first place, then blew the headgasket. If that is the case, whatever caused it to run hot has apparently not been fixed. Both thermostats (it has two in one housing, side by side) have been replaced. Upon discovering that it still overheats, my buddy removed one thermostat and drilled holes in the other to improve coolant flow. That did not fix the problem.

He asked me whether I could have put the gaskets on backwards. Thinking back, I remember paying attention to that, and I'm pretty sure the gaskets were labeled "front" on one end of each. I also think I remember making sure the gaskets were installed correctly based on the fact that they were labeled. I'm not even sure the ft motors will overheat if the gaskets are put on backwards, but I didn't want to take chances.

The radiator is not obviously plugged, either internally or between the fins. I have not personally driven the truck enough to tell whether it is overheating at low speeds, high speeds, or both. The static timing is set about 4 degrees advanced from spec, which it seemed to like. Also, the plugs look bone white, which would indicate to me that it could stand some mixture richening. The thing is, I don't see that making it run hot unloaded, which it is. What ideas can you guys come up with?

 

I'd pop this question up in the FE forum. I don't think the FT is any different than an FE on the heads. If so, then the gaskets will go in backwards and will cause overheating problems if they are installed backwards. That being said, if you've got the front label to the front then you've got it right. Do you have an aftermarket temp gauge with #'s or are you going off the factory gauge. I recommend an aftermarket gauge to be sure you know what the temp is. Are you certain that you don't have a compression leak into the water jacket now? You could still have a head gasket leak or a crack either in a head or block that can leak compression into the water jacket. If so, this can cause overheating. It does sound like it's possible it had the overheat problem before and that's what started this chain of events.

Good Luck!

Tracy

 

Good points. It has a recently-installed aftermarket temp gauge, so we're not relying on the factory gauge anymore. I THINK the heads were crack checked. The machinist who surfaced them is a long time good friend of mine, and I'm sure that if he was told to check them for cracks, he did. Thing is, I'm not the one who took him the heads, so I can't vouch for what he was told to do to them. I guess if the waterpump turns out to be good and the radiator is not clogged, we could do a compression test to see if pressure is leaking out into the cooling system like you said.

I think I'll post it on the FE board too. I didn't realize there was a forum here for just those engines, though I was kind of in a hurry when I posted originally.

 

You solved the problem, the timing is too far advanced, the plugs being bone white are indicative of the high temps in the combustion chamber.

 

If the timing is not it, maybe a leakdown would determine if there is a crack. Just for kicks stick waterhose in the rad fill,drop the top rad hose and rev the thing up and see what makes it's way outa the hose. I'd be curious whats behind the freeze plugs in it ...mud in the bottom ? If it's timing or fuel mix these are easily refined. I'd start by pulling the #1 plug and verifying the damper is a 0 when the piston is a TDC, if thats good, check the vac/mech advance parts for gunk/failure(diaphram).