71 F250 360 smokes and rough running

[Redcrew71]

Hi...just picked up this Custom Sport all original only about 120000 miles. Drove home bout 10 miles. bad blue smoke. Very rough running no power. First thing is I replaced the Spark plug wires. That helped some....found the main centre wire to be corroded and broken...lots of cracks on others.

Truck starts fine and now idles bit better not threatening to stall. still smokes and no power hit throttle and has hard time to rev up like bogged.

Anyone have any thoughts? have not dived into the carb yet for tune as it starts and runs. thinking of opening valve covers up to see what its like. maybe replace the valve stem seals. Aside from these seals being toast if they are would that be the main source of smoke and bog? not looking at going to bottom end yet. was thinking valve stem seals, replace gaskets for heads and valve covers and maybe intake as its laiden with oil.

how hard is it to take off heads and intake...I heard the intake is a bear to get off any tips?
thanks

[markguiver]

Do you know how long the truck was sitting prior to your purchase? As much info as you can provide helps with any diagnosis. The first thing that comes to mind that may be the cause of the blue smoke/no power is the carb. Could be the carb is full of varnish, choke is sticking, or the float in the bowl is bad and is full of gas causing it to flood. In any case I would replace the oil and filter, antifreeze, plugs, plug wires (which you did), distributer cap and rotor, and any fuel filter that is inline. If it were mine I would give the carb a once over before pulling the intake. I would pull the valve covers and see how much crud is built up on the top end. If it's cruddy run a can of engine flush before changing the oil. A compression test would also help to determine the overall health of the engine. There are other tests you can do but first start with the basics.
Mark

[Ohiotinkerer]

Start simple and look for the obvious - a lot easier and less aggravating...........

[tnlprt]

Pull the plugs and read them

Single or dual exhaust?

Are the intake gaskets blue?

[Redcrew71]

Thanks guys....single exhaust looks like black gaskets. I know my left is leaking or cracked not sure yet.

Was sitting for a while yes last few years. previous guy replaced the points. Agree going to do the oil flush, then new oil, fuel filter, have new plugs already. Its going into storage right away for the winter as it has no heat and I will just be using for summer runabout but was hoping to put it away with fresh fluids and a cleaned out engine and gas as much as possible

truck good (800x600).jpg

[Redcrew71]

Pull the plugs and read them

Single or dual exhaust?

Are the intake gaskets blue?

The plugs are black and slight grey on the tip. not solid wet.

[farmallmta]

Congrats on your acquisition! Now the real fun begins!

Pull the valve covers and lower the oil pan and look to see how badly the gunk buildup is, taking the opportunity to replace those gaskets with GOOD gaskets. If it's gunked, you don't want to do anything like a "flush" with a cleaning additive since that's going to break crud loose and block oil passages.

Once an engine ceases to be maintained properly, it's amazing how quickly problems accumulate, accelerate, and cascade into other problems, creating a can of worms that can be hard to individually diagnose. A poorly maintained engine is almost always going to have some if not most or all of the following problems:

1) carburetor varnished, out of tune, leaking (fuel and air), rough idle and rough running, poor throttle response, clogged filter at the bowl (if any). Remove and have rebuilt by an experienced and competent carb specialist: almost every shade tree mechanic thinks he is, almost none are. Get it done right. Also check the fuel pump, fuel filters, fuel tank for leaks and rust/dirt/water and fuel lines for blockages (these can give very transient symptoms of fuel starvation and then go away quickly... for a while). Make sure the air breather is present and actually filtering intake air.
2) Ignition pathway very sketchy: wires, points/condenser (or alternative), plugs, cap, rotor often need replacing. Just do all of it.
3) thermostat sticking or blocked
4) vacuum leaks, lines cracked and often routed wrong
5) PCV inoperative or missing or sticking, oil breather caps blocked partially or entirely
6) ignition timing off
7) worn/burned valves and valvetrain out of proper clearances and adjustments
8 ) broken/worn rings
9) scarred/scratched cylinder walls
10) worn main/rod bearings and wrist pins and rod bushings.
11) never saw one yet that didn't have bad gaskets everywhere
12) blocked exhaust passages, often the muffler rotted and collapsed internally.

There are more, but this could keep you busy for a while. Happy wrenching!

[Redcrew71]

Well...
Ran a can of Seafoam through the carb.
Took out no power. Runs okay at idle when go out can put thing to the floor no power bogs very slow to build speed wants to die on slowing down and turns.
Adjusted carb 11/2 turns about seems to idle bit better not spectacular.
Blew some choke starter around base of carb no change in idle.
Going to take valve covers off and inspect. Have new valve seals will see. bad smoke may be from the valves.
Going to change oil after as well as its black black black.
Also going to replace fuel filter. it has the grey canister one.

and on....

[Redcrew71]

Okay so not good. took valve covers off and there is a few valve "lifter/push rods" sorry dont know term that are bent and two are out one is completely gone. that would explain the smoke and no power.

total rookie here....just looking for run about here or there. can these rods just be replaced?

further issues? why do they bend break?

[farmallmta]

most encountered possible reasons for bent pushrods:

1) varnished fuel deposited on the valve stems causing failure to slip in the valve guides... pistons strike the valve thereby pushing the valve stem against the rocker which in turn pushes the rocker against the pushrod. Since the pushrod is the weakest in the line, they bend

2) engine has jumped time due to worn timing belt and the valves/pistons aren't in synch, so the pistons strike the valves

If it's just a couple of pushrods that are bent, it's likely varnish. Either way, the heads come off and valves get replaced. MIght as well do a whole valve job, rebuild the heads. It's likely time.

[farmallmta]

Years of experience talking to you here:
There is nothing worse than a sh!tty running/driving vehicle (okay, a foul tempered woman is slightly worse ). Chances are high that it's likely going to need a thorough going through. You're looking at time and money. If you try to half-way it on the cheap, you're going to grow to HATE that truck . Just get the engine out and have it gone through during the winter. If you don't want to spend the money, save your sanity and get rid of it, instead find something that's ready to go. Going through what you have is likely going to be cheaper, though. Plus it's a bumpside, the very vehicle God drives around in Heaven when he's checking the pastures up there.

[Redcrew71]

Thanks guys...the truck has sat many years. only has 120000 miles. I got new rods...have sprayed down the valves and will let it sit overnite. will see if I need to break free the valves tomorrow before reinstalling. I have found 3 that are broke/bent not doing anything. All the rest are great. Very little wear on them as well. I can barely tell the difference between the new and old.

I am not looking to do an engine or rebuild in this yet. I am handy but deeper engine mechanics not my thing. I would sell as is if I had to.

[Jacksdad]

Bent pushrods won't make it smoke. Bad valve seals or stuck piston rings will.
I agree with not doing an engine flush - if the motor has a lot of gunk build up and you break it all loose, it'll potentially clog the oil pump pick up and starve the motor. Get it running, and regular oil changes will help clear it out gradually.
You're on the right track with the valves. Pull the rocker shafts, and squirt penetrating oil between the valve spring coils on to the valve stems above the seals. Tap the valve tips with a hammer, but don't go nuts because you don't want them to hit a piston and potentially bend them. You just want to see some movement and allow oil to make it's way down the guides. Keep tapping and soaking until they all start to move. If you don't free them up, they'll just bend the new pushrods again. Marvel Mystery Oil (MMO) would work too.
And while it's sitting there, pour some MMO down the spark plugs holes and let that soak at least overnight - longer if you can. I'd be surprised if you didn't have at least some stuck piston rings. They'd contribute to the rough running and blue smoke. It'll smoke like crazy when you start it up, but that'll clear pretty quick. By the way, your neighbors downwind will hate you
Don't go crazy just yet - undo some of the damage that sitting for long periods causes and then diagnose any other problems you may have. You might be lucky.

[Redcrew71]

thanks for the info.

question for the oil drain hole are their just on each end or more? does it go straight down? my one end is plugged.

[Redcrew71]

Well great news...valves all moved in head...none stuck. Replaced push rods...gave everything a good cleaning. Not really much gunk in the head except for the far end a bit where the hole was plugged.
Reinstalled valve covers changed oil.

It fired right up. Went for a drive now I have power...wow. like a regular old truck.

Smoke is pretty much gone but little here and their. I suspect it will be a bit to get all that old oil to burn out.

Now....get carb tuned. check timing, replace fuel filter.