460 that "needs mains"
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Joined: Mar 2004
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From: Columbia, MO
460 that "needs mains"
This story sounds so funny that I just had to run it by you all. I went to look at an '82 F250 4x4 with a 460 and 4 speed the other day. Price is $500 and the motor is bad. Story goes, "I can pull start it and it runs fine, but the mains are shot so the crank moves around too much and you can't start it with the starter." "So-and-so had the transmission out and said he could hold the flywheel and move it up and down in there."
As far as the seller is concerned, the engine would be fine if a person were to put new main bearings in it.
Now, I can see that if the main bearings were absent or something, we might have this sort of problem, but I just don't quite buy it. Not to mention that the rest of the engine is likely done due to the lack of proper oiling if, in fact, this is the scenario.
So, has anybody seen a 460 with bad mains (or more likely, some other problem) that exhibited this sort of behavior? I'm not a big inch ford guy by any means so maybe it's common and I just don't know about it.
Sorry if I've bored you or left out any pertinent info.
Thanks,
Clem
As far as the seller is concerned, the engine would be fine if a person were to put new main bearings in it.
Now, I can see that if the main bearings were absent or something, we might have this sort of problem, but I just don't quite buy it. Not to mention that the rest of the engine is likely done due to the lack of proper oiling if, in fact, this is the scenario.
So, has anybody seen a 460 with bad mains (or more likely, some other problem) that exhibited this sort of behavior? I'm not a big inch ford guy by any means so maybe it's common and I just don't know about it.
Sorry if I've bored you or left out any pertinent info.
Thanks,
Clem
Junior User
Joined: Oct 2004
Posts: 65
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From: new brunswick
total engine rebuild
hi if there is that kind of movement in the crankshaft you have some big problems.the motor will have to be rebuilt top to bottom no shortcuts and may need a new crank.look at spending $2500 or more to get a good reiable engine that makes good power and will give you many years of service.if you were just to try a cheap fix it would only end up being disappointing and more expensive in the end and dont forget alot more work pulling out motors 2 or 3 times and not very reiable either.hope this helps ken
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Joined: Apr 2004
Posts: 152
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From: Southeast GA
If all the mains had that much clearance it would be knocking like crazy. However, if the thrust bearing, the center main bearing were worn out on the 'thrust' flanges, the crank could go forward and aft and cause cranking problems via the starter.
Speaking from experience...my '64 Ranchero fits this to a tee. If you depress the clutch pedal while cranking the motor, the starter drive hits the flywheel and sings like crazy. Put it in neutral and it cranks fine. You can take a prybar and move the crank in and out by probably .080-.100". Even when it's idling, you can have someone mash the clutch pedal down and see the harmonic balancer move back and forth. It never knocks or rattles and consistently holds over 45 psi oil pressure. It's currently "under construction" so I just crank it once in awhile. I plan on dropping the pan and rolling in a new thrust bearing before long and see just how long it'll keep going.
Speaking from experience...my '64 Ranchero fits this to a tee. If you depress the clutch pedal while cranking the motor, the starter drive hits the flywheel and sings like crazy. Put it in neutral and it cranks fine. You can take a prybar and move the crank in and out by probably .080-.100". Even when it's idling, you can have someone mash the clutch pedal down and see the harmonic balancer move back and forth. It never knocks or rattles and consistently holds over 45 psi oil pressure. It's currently "under construction" so I just crank it once in awhile. I plan on dropping the pan and rolling in a new thrust bearing before long and see just how long it'll keep going.
