Riddle me this Mechanic Man?

[savatreatabvr]

On a recent thread I started I posted some pics of my spark plugs, the pics looked great until 3 hours later and now only 1 out of the 3 are viewable so I'll post them again with my original question! A month or so ago my 454 was running rough so I pulled the plugs, cylinder #4 was dirty (pic #1) so I cleaned it and she ran fine. Last week it started running rough again so I pulled the same plug and it was ten times worse (pic #2) but after I cleaned it again shes running better than ever! What the heck causes spark plugs to foul like this?

PIC #1



PIC #2





Any idea's on what my problem is?

[yousesteers]

seems like all the trucks I have ever owned have fouled the back 2 pkugs first but not as quickly as you are talking is the truck burning any oil

[bustedknuckles]

Definitely looks like oil to me. Watch your oil level very closely. How old is the engine? What oil do you run?

[savatreatabvr]

The truck is a 73 C20 Custom Deluxe that originally came with a 350, some where down the line somebody dropped a late 70's 454 in it. It doesn't smoke when first fired up, it smokes a little after idling a while but check this out, I added a quart of oil last week and the truck smoked like a pig for a few miles then cleared up so I'm assuming some oil ran down into a cylinder and then burned off? So what's that, the valve guides or valve seals?

Originally Posted by bustedknuckles

Definitely looks like oil to me. Watch your oil level very closely. How old is the engine? What oil do you run?

[bustedknuckles]

Sounds like valve seals.

[savatreatabvr]

Same here, it's always the hardest plugs to get to but this time it's #4. It doesn't burn as much as you might think, I'm saying 1 quart every few months maybe.

Originally Posted by yousesteers

seems like all the trucks I have ever owned have fouled the back 2 pkugs first but not as quickly as you are talking is the truck burning any oil

[savatreatabvr]

Which ones are replaceable with the heads still on the engine, the guides or seals?

Originally Posted by bustedknuckles

Sounds like valve seals.

[savatreatabvr]

I used Quakerstate last time. Should I use synthetic oil?

Originally Posted by bustedknuckles

Definitely looks like oil to me. Watch your oil level very closely. How old is the engine? What oil do you run?

[bustedknuckles]

In my experience synthetic is no good for older engines. I am a big fan of Castrol 20w50. Of course, I live in TX and the weather permits me to run this year round. IMO The higher viscosity is better for an older engine. Loose clearances need heavier oil to keep the pressure up. But if your valve seals leak like that the only fix is replacing them.

[INSIDIOUS '86]

+ on the valve guides and stem seals being the culprit

if you replace the stem seals and the guides are rather worn it will just wear down the seals again in a couple months have a machinist check the play in your valves when the springs and seals are off

[rwhit57]

I had a big block that did that, ended up being the return holes in the head were full of gunk not allowing the oil to return to the pan. You might pull the valve covers and take a look.(It still could be bad valve seals but this just adds to the issue) Also what weight oil are you running? In Ariz. if it were me I would probably run some Valvoline racing oil straight 30 or 40 wt.

I noticed in the pic it looks like your running the pcv off the drivers side, you could add one to the pass side and tee it that way it pulls pressure evenly. I don't know if this is a big deal but it couldn't hurt.

[savatreatabvr]

I've never heard of running 2 PCV valves before but it makes since. The PCV is now on the passenger side but thinking about it when it was on the drivers side is when it smoked the most so something is up with that I just don't know what?

Originally Posted by rwhit57

I had a big block that did that, ended up being the return holes in the head were full of gunk not allowing the oil to return to the pan. You might pull the valve covers and take a look.(It still could be bad valve seals but this just adds to the issue) Also what weight oil are you running? In Ariz. if it were me I would probably run some Valvoline racing oil straight 30 or 40 wt.

I noticed in the pic it looks like your running the pcv off the drivers side, you could add one to the pass side and tee it that way it pulls pressure evenly. I don't know if this is a big deal but it couldn't hurt.

[BigBlocksRule]

Terrible ring seal on the 454 is my bet.
Even new crate big blocks aren't torque plate honed when built, it causes blowby and oil consumption issues on brand new engines.
The smoking after adding a quart doesn't make sense, it runs down into the pan, doesn't stay in the head. Are you sure you're not way overfull?

[Hotrodrobert]

Originally Posted by savatreatabvr

I've never heard of running 2 PCV valves before but it makes since. The PCV is now on the passenger side but thinking about it when it was on the drivers side is when it smoked the most so something is up with that I just don't know what?

Two PCV valves will cause problems. The system is supposed to draw air from one side of the engine and pull it out the other side to evacuate all the gasses and fumes in the crankcase. If you use two PCVs, you will create a vacuum in the crankcase(if your rings are good, otherwise you will actually create pressure), Some cars, BMW, some VW, others, do use vacuum in the crankcase but they have seals on the crank to make this work. You don't have these.
If you replace the seals without removing the head, just HOLD THE VALVE and release the air pressure and wiggle the valve stem up and down. If it moves enough to feel, you need to pull the head and replace the guide-usually you will need most or all the guides.

[rs72z]

Pull your valve covers and check the drain back holes. If they are stopped up with sludge it will do exactly what you described. Goes your truck have a/c? If not you can probably change all of the valve stem seals with the heads on the truck.

[savatreatabvr]

Follow me closely here I'll try to explain this so everyone can understand. When I first bought the truck it ran bad, really bad so I replaced the plugs, wires, cap, rotor, put a kit in the Quadrajet and adjusted the valves and it ran much better. While adjusting the valves cylinder #5 was so tight I had to back out the rocker arm nuts 3 full turns before they started tapping but that's not the cylinder that's fouling the plug. Anyways the motor started smoking at idle after that so I moved the PCV to the passenger side valve cover with the baffle and the smoking has almost stopped but that's the side that keeps fouling the plug! Yeah, so that's when I stopped, shook my head in disbelief and laughed and decided to see if someone in this forum had any helpful advice!

[savatreatabvr]

I'll pull the valve covers later today and see if the holes are blocked, I kinda doubt it because it all looked pretty clean when I was adjusting the valves but you never know!

Originally Posted by rs72z

Pull your valve covers and check the drain back holes. If they are stopped up with sludge it will do exactly what you described. Goes your truck have a/c? If not you can probably change all of the valve stem seals with the heads on the truck.

[manimal]

Check for an intake manifold leak. It will have a vacuum leak,sucking oil into the port and foul plugs.You will have to pull the intake to see.

[rs72z]

Originally Posted by savatreatabvr

I'll pull the valve covers later today and see if the holes are blocked, I kinda doubt it because it all looked pretty clean when I was adjusting the valves but you never know!

Ok. Think about one of the rocker studs may have backed out when adjusting the valves, and is now pulling oil aound the stud into the intake port, Very possble.

[BigBlocksRule]

I think manimal's suggestion sounds like something you should check, it'll sure suck oil in through the intake from the lifter valley and produce the symptoms you're describing.

[78 Chevyrado]

Spark Plug Chart

Is the PCV Valve working properly? if its plugged up, it can cause a buildup of pressure under the pistons that can force some oil past the rings into the chambers.

As Bad as thats Fouling it, seems like an oil control problem with a piston ring or bore, or either a severe leak at the intake manifold mating surface.

[savatreatabvr]

Makes since bit I sprayed WD-40 all over the intake and didn't find any leaks but I'm not the brightest bulb on the tree so I'll check again!

Originally Posted by manimal

Check for an intake manifold leak. It will have a vacuum leak,sucking oil into the port and foul plugs.You will have to pull the intake to see.

[savatreatabvr]

The PCV valve has got pretty good suction!

Originally Posted by 78 Chevyrado

Spark Plug Chart

Is the PCV Valve working properly? if its plugged up, it can cause a buildup of pressure under the pistons that can force some oil past the rings into the chambers.

As Bad as thats Fouling it, seems like an oil control problem with a piston ring or bore, or either a severe leak at the intake manifold mating surface.

[rs72z]

Originally Posted by savatreatabvr

Makes since bit I sprayed WD-40 all over the intake and didn't find any leaks but I'm not the brightest bulb on the tree so I'll check again!

Spray carb cleaner around the ports to find a leak. But if it's leaking on the bottom it wont show up spraying the outside.

[savatreatabvr]

How can a ruptured fuel pump diaphragm also cause my problem?

Originally Posted by 78 Chevyrado

Spark Plug Chart

Is the PCV Valve working properly? if its plugged up, it can cause a buildup of pressure under the pistons that can force some oil past the rings into the chambers.

As Bad as thats Fouling it, seems like an oil control problem with a piston ring or bore, or either a severe leak at the intake manifold mating surface.