All right hoping for some opinions. I went to look at a 93 f150 xcab 2wheel drive with the 5.8l motor. Guy said he had truck since new had no problems. So I took it for a quick ride around the block drove great. It only had 132000 iles so I bought it. Started home got on the hwy maybe 10 mile started knockin and pinging and started blowing a ton of smoke out of the exhaust. It felt like it was overheating but it wasn't. I checked oil and antifreeze both ok neither one was in the other. So I dont know what to ake of it. Does anyone have an idea about what could be wrong?
It is burning oil for sure. But what could have failed?

Thanks in advance.

 

well it maybe just coincidence...IDK
are you low on oil after getting it home? how low? how many miles traveled to get it home?

what color was all this smoke/exhaust? does it still knock after getting it home...aka when on a cold start?

maybe start by doing a compression check , recording the readings.

a good tune up wouldn't hurt...might be a vacuum line came off
change the PCV...plugs, oil and filter. carefully inspect the plugs- noting which hole they came out of.

make sure the tranny isn't low on fluid, presuming it has a automatic.

then again it maybe just a valve cover leaking on to the exhaust.

 

I hope the truck was a really good deal.

Does it still run and sound good when cold?
You said "felt like it was overheating, but wasn't" explain. Does the truck have a temp gauge?
Knocking and pinging sounds like a vacuum leak or timing WAY off. Blowing smoke out of no where sounds like a a major oil leak. Enriched nailed it, I'd guess an oil line blew causing both both problems The dilemma is, I don't think there are any "oil lines" unless there's an oil cooler added.
Check your oil filter, oil pressure sending unit and drain plug These are the only things that I can see could be the problem.

If it still seems to idle good cold, start it up in your driveway and watch it. See if you can tell where it's leaking oil or smoking from.

 

I suspect/speculate that this is a townie ...meaning that it was rarely driven more than 10 miles away from home ( hence low miles for a 93')...so odds are good that the engine is sludged & carboned up...the OP then drove home 20-50 miles it got everything percolating really well, which might match to it "seemed hot"....toss in a leaky valve cover gasket or tranny line weeping on the exhaust = "lots of smoke", & a sticky T-stat and a radiator long over due cooling system flush. Not to mention what little vermin packed away in the muffler or engine valley.

worse case scenario, swap in a better running engine out of a salvage yard.

 

What I meant by its seems like it was overheating. I have driven cars before that have overheated, and they have no power and they make alot of knocking under throttle. That is exactly what it felt like under any throttle it was knocking and smoking like a train. Bluish smoke smells like oil. but once i was able to get going it would smoke only a little bit with little or no throttle but going up a hill or incline where I had to push the peddle it smokes like hell out the tailpipe. So I am pretty sure I dont have a leak! The truck ran fine when I first got it on the road andd even the hiway for about 10 miles then on the hiway it started running alittle rough then the smoke and no power. It seems alittle better when cold but still has smoke. I just cant figure in my head what possibly failed catastrophically in an instant in an otherwise great running truck???

I have already ordered a new reman 351 for it but I still need to know what went wrong.

 

with that info...top suspects are....may have lost a head gasket...or a lower intake gasket....also a possibility is a a broken/gummed up rings on a piston or two. Maybe a outside chance of really bad valve stem seals.

If you really want to know, then plug the spark plugs , noting which cylinder each came from. The plugs that are all oily and nasty looking will be the chief suspect area. follow up with a compression check.

once your get the reman engine swapped in...tare the original engine down and you'll get to the root cause...learning a bunch along the way