Mechanical Problem : 1992 F-150 351w 5.8l Engine Knock?

[Smossy]

Picked up a 92 F150 5.8 longbed that vehicle wise is in great condition, Mechanically it has a few issues. Only has 160k miles so someone really made a mistake somewhere.
For one I noticed the wiring as been messed with quite severely and not in a good way. Some 0 gauge wires dangling free and just pressed under some random bolts. Used red wire for grounds, so yeah kind of messed.
In addition to that when I did manage to get it to start, it had a really bad sounding engine knock. Not a pretty noise. Literally sounds like a hammer hitting metal over and over. It idled fine and kept running although the sound is something that makes you want to shut it right off. So I'm assuming theres some real damage somewhere.
Pockets are pretty shallow so its gonna take me probably years to get this thing drivable.  Figured I'd get to work on my own little outdoor rig.
Should I risk rebuilding or trying to find a new or used motor?
Figured there has to be a few guys on here with experience on these motors being as they're so common..
Alittle added thing, the guy I got it from said it ran fairly decent untill gus buddy changed out the freeze plugs, now it's in the shape it's in now. At this point aw ith a full battery I can't even get it to crank, assuming because the masses of wires that need to be fixed.

[Smossy]

Payed $800

[NRA4LIFE]

That looks to be in remarkable shape!  Maybe an engine rebuild?

[Smossy]

That looks to be in remarkable shape!  Maybe an engine rebuild?

Yeah it really is, last thing I wanted was another non-running vehicle but for the price I couldn't pass it up. Hopefully some ford vets will chime in on this motor, I Know it's the same motor that's in the 250 and 350 of that era, even some older mustang's given some added hp mods.  Rebuild would be cheaper but it's just a matter of if what's going on with it is some "fluke" and it's really not as bad as it sounds, or its gonna be completely messed up inside.

[CP]

A "knock" could be a lot of things, none of them good.  A new (rebuilt) short block will correct most problems of that type.

[Smossy]

A "knock" could be a lot of things, none of them good.  A new (rebuilt) short block will correct most problems of that type.

Yeah I figured, something like this then?

https://spprecision.com/products/351-windsor-short-block-engine-sale.html?gclid=Cj0KCQjw3InYBRCLARIsAG6bfMT6l-pglHpdoTxdj99Watuiuh8QJQkFnaSXHoUAZBvAbd_uQ0dxJr4aAvKKEALw_wcB



Odd...

From the website
Production Years Covered
1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1994, 1995, 1996, 1997

Literally skips 1992, wonder what's different? Short block just means the upper right?not the complete upper/lower "longblock"?

[Crunchy]

I would start by either dropping the oil pan or draining some oil looking for metal shavings.  If that looks good try a compression test, if possible, to see if you have an issue with one of the intake or exhaust valves.  Thrown rod, broken or bent valve, broken valve spring all come to mind.  Depends on how bad the knocking noise is. 

[CP]

A "knock" could be a lot of things, none of them good.  A new (rebuilt) short block will correct most problems of that type.

Yeah I figured, something like this then?

https://spprecision.com/products/351-windsor-short-block-engine-sale.html?gclid=Cj0KCQjw3InYBRCLARIsAG6bfMT6l-pglHpdoTxdj99Watuiuh8QJQkFnaSXHoUAZBvAbd_uQ0dxJr4aAvKKEALw_wcB



Odd...

From the website
Production Years Covered
1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1994, 1995, 1996, 1997

Literally skips 1992, wonder what's different? Short block just means the upper right?not the complete upper/lower "longblock"?

A short block does not include the heads, just the crank, pistons, etc. 

There are different versions of the 351 out there e.g. 351M, 351C, 351W - I believe the W is a small, block the others are a "big" block, but I'm no expert - do your research.

[Zardoz]

A "knock" could be a lot of things, none of them good.  A new (rebuilt) short block will correct most problems of that type.

Yeah I figured, something like this then?

https://spprecision.com/products/351-windsor-short-block-engine-sale.html?gclid=Cj0KCQjw3InYBRCLARIsAG6bfMT6l-pglHpdoTxdj99Watuiuh8QJQkFnaSXHoUAZBvAbd_uQ0dxJr4aAvKKEALw_wcB



Odd...

From the website
Production Years Covered
1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1994, 1995, 1996, 1997

Literally skips 1992, wonder what's different? Short block just means the upper right?not the complete upper/lower "longblock"?

Down in the "Specs" it covers 92-93. Probably have to call them and see if whats special about yours.

[Bofire]

you do not know about the motor, freeze plugs are not replaced for fun. Knock. Find a used motor, buy a short block, rebuild it, get the heads done too. Hows the brakes and tranny?

Carl

[Smossy]

you do not know about the motor, freeze plugs are not replaced for fun. Knock. Find a used motor, buy a short block, rebuild it, get the heads done too. Hows the brakes and tranny?

Carl

Everything else seems solid... just...the sound...

[Mudman]

Freeze plugs?!?!  Red flag.  Its a boat anchor probably.  Buy a good runner used/wrecking yard etc.  Rebuild will cost ya more.  Nice truck.  Drop the oil pan and inspect for metal shaves and damage first.  Wires could just be some radio/cb/light mods?  Trace em to source and repair/remove.  Ground doesn't care if its red/black/white!  I have used red!

[Smossy]

Freeze plugs?!?!  Red flag.  Its a boat anchor probably.  Buy a good runner used/wrecking yard etc.  Rebuild will cost ya more.  Nice truck.  Drop the oil pan and inspect for metal shaves and damage first.  Wires could just be some radio/cb/light mods?  Trace em to source and repair/remove.  Ground doesn't care if its red/black/white!  I have used red!

Lol I know it doesnt matter, just makes it alittle more anoying when tracking them down. Wires look like they just cut out the factory stuff and replaced them with bigger wires and did a poor job. Yeah oil pan will be the first thing I do, hell I dont even remember if I even checked if it had oil in it 😳, I've found a few cheap running vehicles for 3-500. Just dont know 100% if they will swap. One chick has a hideous van with a cartoon pain job on the side for 300 but it runs.

[jackelope]

I missed the part about it already running, albeit poorly.
Wonder if he broke the flex plate putting the engine back in it after doing freeze plugs? If there's an inspection cover at the bell housing you can pull and look? Just a thought.

[Smossy]

Gonna get my hands dirty after work and see what I can find