I'm in a quandary!(400 to 460?)

[fatherdoug]

Some background: I have a '78 with a rebuilt, stock 400 motor that has done really well, except it overheats when pulling a trailer. The only time the truck overheats is when pulling an 18' camp trailer.

Everything in the drive train is new or rebuilt, including the cooling system: new radiator(super cooling), water pump, fan clutch, shroud, large tranny cooler, etc., etc.

Timing is set at 10 BTDC. I had the engine rebuilt because the engine that came with the truck had the same problem, even though it had been rebuilt(unbeknownst to me).

Because of the overheating problem with the '78, I purchased an '89 F-250 HD with an EFI 460(new rebuilt engine) for the sole purpose of pulling the trailer on the annual camping trip. I have put less than 5000 miles on this truck in 5 years.

I am considering putting the 460 engine from the '89 into the '78. That way, I would only have to deal with one truck that could handle both tasks.

I need some advice on how to handle this: sell the '89 and use the money to purchase a 460, or install the EFI 460 into the '78.

Better yet, someone might have an idea on the overheating issue.

 

[O'Rattlecan]

I won't be able to be detailed enough to be helpful, but the EFI in the 80 relies upon a lot of different components that your 78 does not have. The EFI relies on a computer in the firewall, uses the main wiring harness that goes to that computer, and that wire harness strings to almost everything under the hood. Now, you can trim this harness and easily cut out all of the stuff you don't need, but it might be a good deal of work.

The other thing that occurs to me would be fuel pressure. Those carborated motors use a lot lower fuel pressure (I think) than the EFI motors. This is something you could work around, but it would be another hurdle for you.

Ryan

 

[Mil1ion]

You would need most of the drive train components of the EFI truck and the rear axle gear ratio has to be the same.
Other than the fuel delivery components there are a few feedback components that have to be considered.
The computer fits a certain configuration and can't be exchanged using the wrong parts.

Perhaps you over heating issue is because of the rebuilt engine.
Rebuilt engines can over heat until they are more broken in.
Timing has a lot to do with overheating as well.
Maybe it needs fine tuning ?

 

[fatherdoug]

Thanks, Ryan and Dennis. I understand I would have to overcome some major hurdles. Perhaps I would be better off selling the '89 as is and reinvesting in another 400(TMI comes to mind) or a carbureted 460?

The rebuilt engine has about 25,000 miles on it. I would assume the breakin period would be done by now.

 

[m78]

Back when I was building that jeep , I started with a 307 out of a nova. It would over heat at higher speeds then slowly come back down at slower speeds.
When I started taking it apart I found a lifter that was cupped really bad on the bottom and the lobe on the cam shaft was slightly worn.
I changed that one lifter and a new cam , put it all bac k together and no more over heating.
I never heard it tap or anything.

 

[fatherdoug]

Interesting, Mark. This engine does the same thing. When it is under a load, the temperature increases, up to about 220+ degrees, then when the load is released(as in going up/down a hill), the temp comes right back down to 190 degrees.

 

[DNFXDLI]

Did you establish whether or not your timing gears were straightup?

 

[fatherdoug]

Did you establish whether or not your timing gears were straightup?

Yes, my truck is retarded. 4 degrees, that is.

 

[DNFXDLI]

That could be part of your problem.

 

[fatherdoug]

I'll have to work on that!

 

[DNFXDLI]

A hell of a lot cheaper than the other options.

 

[fatherdoug]

Agreed. I'm just trying to draw some info from the fabulous knowledge base on this web site. Was that too much?

 

[DNFXDLI]

 

[primetime]

Have you tried some Redline Water Wetter or similar product? That stuff actually seems to work. I know the roundy round guys around here use it, and my buddy put some some in one of his Cummins Dodge for the same issue, and it solved it.

Some tuning might not be a bad idea. Those old emissions engines run lean, a little more fuel to cool the fire might not hurt.

Of course, a fuelie 460 conversion is cool, and has been done, so there is a path to follow.

 

[SuperCab]

If you're pulling the trailer up a grade does it ever go hotter than 220? Or if you kept climbing would the temperature keep rising till it boils?

220 isn't that bad really. My suburban runs about the same pulling a grade with a trailer on. You could run wide open uphill all day and it would run at 220-225 then once you're on a flat again it will drop to 190. That's just where it runs.

 

[kiwi f150]

Doug have you taken the thermostat out and boiled it to see that it is operating correctly ....... i have found brand new ones that wouldn't open properly before.
What ratio of antifreeze/coolant are you running - too much can actually lower the boiling point rather than raise it.
What pressure cap are you running on the system?
Finally is the engine using water ...... if it is you might have a weeping head gasket or a slight crack in the head which will certainly show the exact symptoms you are describing - if it is maybe you could borrow a pressure tester from someone and pump the radiator up to 18 - 20 psi and leave it overnight then pull the spark plugs and wind it over to see which cylinder the water comes out of.

 

[Fellro]

I too wouldn't get overly excited over 220, as under pressure and with a blend, the boiling point is still much higher. Newer vehicles run at 220 regularly, the cooling fans actually don't even turn on until that temp. If it was boiling over all the time, I would be more concerned.

 

[fatherdoug]

If you're pulling the trailer up a grade does it ever go hotter than 220? Or if you kept climbing would the temperature keep rising till it boils?

220 isn't that bad really. My suburban runs about the same pulling a grade with a trailer on. You could run wide open uphill all day and it would run at 220-225 then once you're on a flat again it will drop to 190. That's just where it runs.

I've haven't been brave enough to see where the temp levels out at. And yes, once I get to a level spot the temp comes down nicely.

Doug have you taken the thermostat out and boiled it to see that it is operating correctly ....... i have found brand new ones that wouldn't open properly before.
What ratio of antifreeze/coolant are you running - too much can actually lower the boiling point rather than raise it.
What pressure cap are you running on the system?
Finally is the engine using water ...... if it is you might have a weeping head gasket or a slight crack in the head which will certainly show the exact symptoms you are describing - if it is maybe you could borrow a pressure tester from someone and pump the radiator up to 18 - 20 psi and leave it overnight then pull the spark plugs and wind it over to see which cylinder the water comes out of.

I have been using the Robert Shaw 190 deg thermostat(when I can find them) and I have tested the thermostats on the stove with a candy thermometer. The three I have had in there all opened at 190 deg.

I am using a 50/50 mixture of glycol, which I need for both the hot AND cold weather here. I did try a 60/40 mixture glycol/water, but, as you said, it reduces the fluid's ability to remove heat.

I am using a 13 lb radiator cap which is oem.

The engine has not used a drop of water since being rebuilt(the second time, anyway)

I too wouldn't get overly excited over 220, as under pressure and with a blend, the boiling point is still much higher. Newer vehicles run at 220 regularly, the cooling fans actually don't even turn on until that temp. If it was boiling over all the time, I would be more concerned.

There is no boiling over. The other issue is my temp gauge. I am guessing at the temp once it gets above 220 deg. It is a Stewart/Warner gauge, but there is some room for interpretation on the dividing hash marks between numbers.

 

[5.0Flareside]

I wouldn't be worried about 220* you could try to swap in a lower temp thermostat. Or try below.. As justin suggested a coolant booster like redline water wetter.. I have a similar product. That there have been many people say it's as good or better than redlined version..


http://www.amsoil.com/shop/by-produ...ator-coolant-boost/?code=RDCBCN-EA&ZO=5224678

 

[5.0Flareside]

Oh and is fan clutch fully working?