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  #1  
Old 07-10-2007, 06:33 PM
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Heads

my pastor has a 360 in his jeep and has had major problems with it since he had it rebuilt. Here is a real quik story of it. Replaced 258 with rebult 360 with Howell FI. Put in jeep and would idle all day long fine but once you start driving it it would get real hot and boil the anti freeze. He is running 2 electric fans with an aluminum radiator, with a probuilt shroud. Took to a different mechanic. Pulled motor to replace head gaskets. Found major problem. Rebuilt motor again. same problem with heating plus head gaskets seeped. SO mechtseing the heads that were on the engine originally, he was able to get the heads back form original mech. Appearently the casting numbers revieil that they were shared between 360's and 401's. and the original heads casting numbers were only on 360's.

So my question is. are all AMC V8 heads interchangeable? Any suggestions on what could be the problem? Supposeable the heads and block were maged. TIA

Mark
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  #2  
Old 07-10-2007, 06:40 PM
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Heads from 360 and 401 will interchange. Was the water pump replaced. Could have a air pocket in it. How about the timing.
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  #3  
Old 07-10-2007, 07:10 PM
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Yup new H2O pump. Timing is good.
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Old 07-10-2007, 08:25 PM
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Was the radiator replaced when the 360 was dropped in place of the 258? Could be undersized. Also consider replacing the radiator cap...pressure is a wonderful thing to prevent boiling over...the pressure raises the boiling temperature of the coolant. Does it have a fan shroud?

Just a few thoughts.
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Old 07-10-2007, 08:43 PM
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Quote:
Originally Posted by etjeep
Was the radiator replaced when the 360 was dropped in place of the 258? Could be undersized. Also consider replacing the radiator cap...pressure is a wonderful thing to prevent boiling over...the pressure raises the boiling temperature of the coolant. Does it have a fan shroud?

Just a few thoughts.


Yup, yup, and yup. the motor was pressurized last out of the jeep and apparently wasn't holding pressure and was bubbling. I am assuming either the head or block has a crack that the magnaflux didn't show or was over seen.
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Old 07-11-2007, 09:45 PM
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Are you sure it is not going lean ?
Are you also sure the timing is not overly advanced/retarded ?

Mike D.
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  #7  
Old 07-12-2007, 11:04 AM
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I'm with Mdill sounds like a lean/timing condition to me. Both together can cause those problems.
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Old 07-12-2007, 11:27 AM
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Quote:
Originally Posted by bluexj89
Yup, yup, and yup. the motor was pressurized last out of the jeep and apparently wasn't holding pressure and was bubbling. I am assuming either the head or block has a crack that the magnaflux didn't show or was over seen.

Sounds like you hit the nail on the head. You said that the head gaskets were replaced and they still leaked. Did they check to make sure the deck surfaces were straight?
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Old 07-12-2007, 11:34 AM
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Does he know if the engine was bored out any when it was rebuilt?
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  #10  
Old 07-12-2007, 01:08 PM
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I agree to be sure the bigger V-8 radiator is in there. The next question on a rebuilt is: was it bored out, and how much. Overheating in 401's is frequently due to overbore. Maybe here, too?
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  #11  
Old 07-12-2007, 04:09 PM
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The 360 was bored 30 over one cylinder has a sleave. It has a huge 4 core aluminum radiator. Howell fuel injection timing is right on the nose. New hoses new waterpump new thermostat. It will idle for hours fine rev it up to 2000 rpm or drive it at 2000 rpm and it will climb to 230+ quickly. The head and blck were both check for true and the heads were decked. Right now it does not leak but when presureized the coolant bubbles.
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Old 07-12-2007, 04:18 PM
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Is the radiator cap lined up with the vent? Is the lower hose collapsing under load? Are you running a 180 thermostat?
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Old 07-12-2007, 10:31 PM
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Quote:
Originally Posted by bluexj89
The 360 was bored 30 over one cylinder has a sleave. It has a huge 4 core aluminum radiator. Howell fuel injection timing is right on the nose. New hoses new waterpump new thermostat. It will idle for hours fine rev it up to 2000 rpm or drive it at 2000 rpm and it will climb to 230+ quickly. The head and blck were both check for true and the heads were decked. Right now it does not leak but when presureized the coolant bubbles.

Ok...the coolant has bubbles in it. Have they checked to see if there CO in the coolant? If one of the heads is cracked, it can leak exhaust gas into the cooling system. This will cause overheating in a hurry.
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  #14  
Old 07-13-2007, 08:08 AM
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Quote:
Originally Posted by Retro93
Ok...the coolant has bubbles in it. Have they checked to see if there CO in the coolant? If one of the heads is cracked, it can leak exhaust gas into the cooling system. This will cause overheating in a hurry.

The heads and block were all supposed to have been magnafluxed. But with all the shoddy workmanship on this engine I am assuming that there is a crack somewhere that didn't get seen. Right now the Mechanic, machinist, and an AMC expert are building an engine stand to run it on before starting over again with a new engine. If I ever have problems I am going to rebuild the engine my self. I am glad I have the capability! I am sure this is going to be a really expensive engine when it gets done right!
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  #15  
Old 07-13-2007, 08:36 AM
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Quote:
Originally Posted by bluexj89
I am sure this is going to be a really expensive engine when it gets done right!

Amen to that!
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  #16  
Old 07-13-2007, 08:43 PM
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Quote:
Originally Posted by bluexj89
The heads and block were all supposed to have been magnafluxed. But with all the shoddy workmanship on this engine I am assuming that there is a crack somewhere that didn't get seen. Right now the Mechanic, machinist, and an AMC expert are building an engine stand to run it on before starting over again with a new engine. If I ever have problems I am going to rebuild the engine my self. I am glad I have the capability! I am sure this is going to be a really expensive engine when it gets done right!
Yeah...it sounds like there were a few rocket scientists working on this thing....
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  #17  
Old 07-14-2007, 03:03 PM
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If the coolant is bubbling while the engine is running you have a cracked head. Only way to find the crack is pull both heads and have them magnafluxed again. Head might be repairable if the crack is near a seat. I'm not fond of welding to seal a crack. Easier to ditch head and find replacement.
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  #18  
Old 07-14-2007, 04:15 PM
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Drop an LS7 in it.
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  #19  
Old 07-14-2007, 04:55 PM
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The Howell TBI does NOT adjust timing (unless they've updated their system in the past 6 months...)

Your timing is still set by the distributor and associated systems.

I'd also look and see if those electric fans are up to the task.
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