400 main bearings
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400 main bearings
Howdy, first time post for me. I just pulled a 400 out of a 76 LTD with only 72,000 original miles and was planning on dropping it in my f-100 in place of the 351M in there now (not original). I bought an edelbrock intake and carb and a mild comp cams kit. The car ran great and I just planned to swap in the goodies and throw it in the truck without rebuilding it. Anyway, when I dissasembled the engine It was really clean inside and the heads looked great. However, when I pulled the rear main cap to put in a new seal I saw that the main bearing was all copper. Not even a trace of silver. I pulled the other caps and found all the main bearings to be the same. The rod bearings on the other hand look ok, just slightly worn. Has anyone seen anything like that before? I've never seen a bearing that was completely worn down to the copper all the way around. It seams especially weird because the rod bearings are not nearly as worn. Anyhow, found another block and I'll see if its any better. Just curious if anyone else has run into this before. Thanks, Jeremya72
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From: The Vieux Ford, Kansas
These motor are kind of notorious for low oil pressure and premature bearing wear is a result. I have heard some of the earlier blocks can crack in the lifter valley and since these guys pressurize the cam a lifters first it doesn't leave a lot of pressure for the mains. I could have just been set up too tight from the factory too, or maybe some bad/dirty bearings originally. Its kind of hard to say.
-Johnboy
-Johnboy
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Joined: Dec 2002
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From: chicago burbs
maybe the rod bearings were replaced some time ago, and the mains looked good then?
if the crank looks good you can probably get away with just putting a set of main bearings in it. a high volume oil pump with a shim on the pressure spring should give enough oil pressure to prevent a repeat
if the crank looks good you can probably get away with just putting a set of main bearings in it. a high volume oil pump with a shim on the pressure spring should give enough oil pressure to prevent a repeat
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