Some serious smoke
 

I have an 81 150 with the straight six that smokes all the time, and it smells worse than regular oil burn. The thing also hates idling for any extended amount of time and seems to consume coolant as well. I'm thinking it's the head gasket. Any other opinions?

Run a compression test and report back with the results.

Is it a automatic? Does it use engine oil and you have to fill it all the time? Does it make any ticking or knocking noises(the engine).

I'll do the compression test this weekend. It's a manual and I would venture every 1000 miles or so it consumes half a quart. I'll record it running soon as well.

300-6 running:
Hopefully that plays. It dark because we'll it's low light and my phone. But that's how she typically idles. If she does for a long time she stalls and is rough to restart.

Ok, just did a compression test.

I tested them from front to back and numbered them as such: 1, 80psi; 2, 110psi; 3, 115psi; 4, 110psi; 5, 100psi; 6, 110psi.

Also of note is that the spark plug for #3 is way corroded and all plugs are black with oil and soot.

What's your oil pressure? How much noise does it make(knocking and ticking). Sounds like this engine may be wore out.

I don't currently have a pressure guage. The idiot light comes on as its stalling. No knocking or ticking.

I think it's close to 287k on it.

I'm actually wondering if I can't just limp her along I'd be better of dropping the Explorer 5.0 I have in. The question then would be how long would the SROD last behind it

If you are not doing burnouts, it could last a long time. I put a c4 out of a six cylinder maverick in my 65 mustang with a 4bbl 302, and people said it had less clutches in the clutch packs and would not last, It's still going strong, but I don't do burnouts and the 302 iI have is pretty mild.

So I'm going along with the 5.0 swap. I'm trying to figure out the the fuel pump eccentric. Worse come to worse I'll put a frame rail mounted electric in with a direct kill switch.

At first glance your engine appears to have good compression, but the thing that I am starting to be curious about is cylinder #1. That is considerably below 100 PSI and that cylinder could have more wear. I would take and put a small amount of oil in the cylinder and do a compression test again on Cylinder #1 and see if it comes up any. If it does then your rings on #1 are worn and is the cause for the below 100 PSI reading. If it stays then same then you could have a valve that is burnt or hanging open slightly.


Cylinder #3 being corroded, is it a white calcium looking build up? If it is that is a sign of oil or fuel additives being burned in the cylinder. Its very well possible Cylinder #3 could be the problem for the smoking in your case and the other engines are just getting some oil in them.


How is your PCV valve? Check that as if that is stuck crank case pressure and vacuum can suck oil out of the engine and could be a cause of the oil on all the plugs. Usually if the oil is getting on the plugs in considerable amount it will turn to a white calcium looking build up as it is burned. That is unless it is just so much oil it is fouling out the plugs and those cylinders are just not firing but since its on all of the plugs it cant be that much to foul them out or the engine would not run.

I did do the oil test in #1 and it bumped up to 200psi. So I'm pretty sure those rings are way bagged out.

The PCV is new, but the smoke is no longer coming from the exhaust its puking crank case gas out of the filler/breather. I haven't read the plugs recently. Though the last time I read #1 it looked pretty good.

If its puking gasses out of the filler/breather then your rings are heavily worn. That is blow by from the combustion process and Ive seen it so bad before that you sit the filler cap down on the cover and it will blow the cap clean off while running.

That's why I'm looking at the swap, I have most of the parts needed to do it, so may as well run easy on the HO and when I get back from deployment have the 300 rebuilt and do some upgrades in the process.