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Harmonic balancer looks like its doing the jig.flywheel is tight no movement with a prybar or when idling flywheel looks ok.No smoke out of exaust except initial start from dry rotted valve guides probally.The engine is a 71 460 in a 78 short bed 4x4 F150 I bought the truck I was told the engine was overheated and locked up.The driver exaust was so hot it burnt carpet through the floor pan.[Wow]This is when the owner noticed something wrong then drove 15 more miles home and said the truck would not go over 20 mph pushed to the floor.[Is this like animal cruelty or what]Never heard of a misabusing something like that.Wonder if he would do that to his wifes car.Then he said the motor wasn't started since,because it was locked up.Wonder why? I bought the truck brought it home put a battery in it and it turned over and started it up,But when idles sounds good except for a small miss on the driverside probally burnt exaust valve not seating.Give it gas and feels like the truck is self destructing from the vibration.Oil level was fine antifreeze levels normal.Oil pressure is barely on the gauge maybe 5psi could no.1or2 main spun locked up then came comepletely out.This is my thought.No knocking at all just a little lifter tick when running[not surprising for an old engine.Engine really don't sound bad.I have heard cars with vacuum lines off sound worse.How often do 460 harmonic balancers go bad? I hate to see what a blue crank looks like if the bolts after being heated would allow tear down without breaking off.Any suggestions would help.

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Mike R.
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32.97.239.33 Vibration
No score for this post December 14 2000, 12:32 PM

I wonder if maybe it has a flywheel for an externally balanced 460 and an internally balanced crank or vice versa. This is a good possibility especially with a transplanted engine. Does it happen to have a hatchet spacer behind the vibration dampener.

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RJP
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198.81.16.43 Might be worth opening it up
No score for this post December 14 2000, 3:08 PM

With all you described [oil press. missfiring and overheated] I would pull the engine and tear it down, you may get real lucky and all it needs is a set of rings, bearings and freshen the heads but I doubt it. If you are planning on keeping the truck I'd rebuild the engine completly, do it right the first time and it'll give you years of good service. Have it balanced too.

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Alvin
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24.11.186.48 Lifter out of bore
No score for this post December 18 2000, 10:47 AM

RJP is probably correct. It doesn't sound like your 460 is going to heal itself. As a last ditch effort, I would remove the valve covers first to check and see if all the pushrods are in correctly. Sometimes when a pushrod bends or breaks, it will allow a lifter to jump out of its bore. This will cause the very low oil pressure and the severe miss that you speak of. It seems that if you had a spun bearing, you would be able to hear it.

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Mike R.
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32.97.239.31 Alvin makes an excellent point
No score for this post December 18 2000, 12:25 PM

I've had this happen probably 4 seperate times with these engines. In each case the pushrod was either bent or broken and the lifter shot out of it's hole. The oil pressure drops down to nothing. The good news is in my situations replacing the pushrod and lifter made it as good as new. Never had bearing damage. I never ran mine for an extended period of time though.

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RJP
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198.81.16.21 I had this happen also...
No score for this post December 18 2000, 3:04 PM

460 in a flat, valve adjuster came loose and the lifter popped out of the bore, Oil pressure went to absolute zero. Reinstalled lifter, replaced bent push rod, fired motor, no problems. But 5 lbs of pressure kinda says bad bearing

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Alvin
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24.11.186.48 Oil pressure loss
No score for this post December 18 2000, 4:45 PM

The amount of oil pressure loss can vary according to which lifter jumped out of the bore. If any lifter jumps out on the drivers side, then you will experience the greatest pressure loss. This is because the drivers side lifters are between the oil pump and the pressure port. Because the lifters on the passenger side are after the pressure port, the gauge could still show the 5 psi.

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Alvin
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24.11.186.48 Corrections
No score for this post December 18 2000, 10:13 PM

I'm sorry. My passenger side and drivers side directions were reversed. Lifters out on cylinders 1 through 4 will result in zero oil pressure. Drivers side could leave 5psi.
 
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