compression readings on a 400
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i ain't rite
Joined: Mar 2005
Posts: 65,511
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From: Marlboro Mental Hospital.
compression readings on a 400
the 78 i picked up last week for a parts truck has a 400 in it. 144,000 miles. looks like it has never been opened up, and it is all there, including original 2 bbl carb and egr. egr is disconnected. the engine has 0 compression in #1, 45 lbs in #2, 150lbs in #4, 150 in #4. 155-165 in 5 through 8. what do you think?? bad head gasket?
i was going to use the 400 in the 79, but i really don't feel like rebuilding another engine. the 351M in the 79 only has 81,000 miles on it, but as everybody knows, bigger is better.
i was going to use the 400 in the 79, but i really don't feel like rebuilding another engine. the 351M in the 79 only has 81,000 miles on it, but as everybody knows, bigger is better.
Thread Starter
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i ain't rite
Joined: Mar 2005
Posts: 65,511
Likes: 5,567
From: Marlboro Mental Hospital.
yea, after i came in and cooled down for a while and thought, you are supposed to run an air pressure test before jumping to conclusions, so i went back out and aired up the cylinders.
both #1 and #2 have exhaust valve problems. whether they are burnt, bent or sticking open, i will have to get into after i pull the cab so i can get the valve cover off.( the a/c box will make it harder to do with the cab on)
both #1 and #2 have exhaust valve problems. whether they are burnt, bent or sticking open, i will have to get into after i pull the cab so i can get the valve cover off.( the a/c box will make it harder to do with the cab on)
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Joined: Dec 2002
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From: chicago burbs
pull the bad side head off and look at the valves. could be a burnt X valve and head gasket between 1 and 2? i've had head gaskets just blow through between cylinders and not give any other indications or problems like coolant leaking or mixing with oil. you could use the heads from the 351M on the 400 block but with 144k on the clock i wouldn't do all the swap work without going through the bottom end with at least bearings/oil pump/timing set. then with the intake and heads off you're only minutes away from a cam and lifters. and you said you didn't want to rebuild an engine....
Thread Starter
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i ain't rite
Joined: Mar 2005
Posts: 65,511
Likes: 5,567
From: Marlboro Mental Hospital.
well, if i am going to go that far, i will do the spare 428. or a 460. or maybe the 6.9 diesel. what the heck. if i am going to do a diesel, i might as well do the 9 liter and allison trans in the corner of the shop.
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