Ok so , 300 I6, 1986 f150. Bought a gasket and seal kit.

I don't know how these valve stem seals are supposed to sit , they are very loose almost look like the wrong size. Are they not supposed to fit on very snuggly? These new ones are so loose they will just ride up and down with the valves? Does this seem strange to anyone?
Is there more than one size? Maybe I got the wrong ones.

Does anyone have any experience with this.
As it it with the old ones ,they look to be the same size so were the wrong ones put on before? I suspect oil is by passing the valve stems.

 

Never worked on a six. But most of the valve stem seals are just "umbrellas". They deflect the oil splash away from the valve guide area. Some engines later on had positive oil seals, and they can be retro fitted to older engines, but they require machine work. The OD of the guide area is machined and the positive seals snap onto the newly machined area.

Like I said, never worked on a Ford inline six. But most of the v8's are the way you are describing the seal. By the time you put it all back together, it can't move much, but it does move some as the valve opens and closes.

 

P.S. When you are installing the seal, wiggle the top of the valve around, see how much play it has. A lot of play means the guide is worn, and that will aggravate oil consumption also.

 

Thanks Franklin.

Does the spring hold it in place? It's not loose , it looks actually too big, although it it snug on the stem itself.

 

The ones I have messed with, not a six, that is how they were.
Snug on the valve steam so once the valve moves the seals will be at the same level nit resting on the guide part of the hesd.
Dave ---'

 

It's snug on the stem. Oil running down the stem hits the seal and drips off the OD of the seal. It just deflects the oil away from the guide area. It's big so it will fit over the rough casting of the guide and be free to move up and down with the valve.

 

Ok Thanks Franklin. They move with the valve, good to know. Now I have to rethink what is wrong, I see my oil steaming out the breather. And black sooty specs blowing out the exhaust. I will swap the head and see if there is a difference, I know where I can get a spare today.

 

Those are umbrella type seals. They are meant to be fairly tight on the valve stem and ride on the stem as it opens/closes. The bottom of the seal is fairly tight when the valve is closed and they enclose the valve stem guide. This allows lubrication to the valve stem and guide.

 

All the seals got pushed all the way up on the stems.

My ex floored it in park and over revved it. I suspect that is what did it.

Do you think that's enough to cause oil to spit out the exhaust? I don't think any thing is cracked , I don't have anti freeze contaminating the oil or anything like that.

 

Did the seal(s) hang on the stem(s) whereas they will not bottom on the guide @ TDC? If so, oil will be able to run freely down the valve guides, especially if out of spec. The oil will be sucked into the intake runner and the exhaust runner. FEL-PRO or BEST GASKETS.

Oh, and measure the stems dia. as at some point the heads may have recieved OS stems.

 

Umbrella type valve stem seals are designed to leak just a little, the sizing on the valve stem itself is carefully engineered. They shield the valve stem and guide from excessive oil.

They move with the valve stem, they don't stay in one place.

 

All kinds of nasty stuff comes out of the exhaust normally. That is not a good place to troubleshoot.

First thing to check would be oil consumption. How much oil does it use in how many miles?

Smoke coming out of the valve cover can be a sign, but that is not caused by valve stem seals that is caused by worn piston rings. 1st thing to check when you have valve cover smoke is pull the PCV valve with the engine running. Put your finger over it, does it suck on your finger? If so, that is working. If not, troubleshoot that, something might be clogged.

If your PCV valve was working, put it back in the valve cover and then see how much smoke you get out of the breather/other port in the valve cover. None means you have a brand new engine. A tiny bit means you have some weare, but there are many miles left on the engine. A good bit means the engine is worn, but you can probably still get some use out of it, just keep the oil topped off. Puffing out of the engine means you have one or more cracked piston rings.

The only time you will see valve stem problems is a little blue smoke out of the exhaust when you rev it up and quickly let off the gas pedal. You will also notice it after coasting down a long hill in gear. High engine revs and the throttle closed caused very high vacuum levels in the engine. Really high vacuum in the engine will pull oil in around worn valve guides and valve seals.

 

That is not good I hope you did a compression check before tearing the head of as this is an indication of excessive piston ring blow-by as long the PCV system is functioning correctly.
If the engine was over rev'd and then it started the likely cause is a broken piston ring, and a compression check would identify suspect the cylinder/s.

 

I did a compression test before I did anything ,all cylinders were within a few lbs of each other, I don't remember what it was I think around 140 or so. I can check again and check everything you guys all said , but not today,I need a beer. I pulled a head from the wrecker this morning ,got home just now, it looks to be in good shape. looks like new plugs in it too.I have a spare at least.

Thank you all.

 

If you are just using black umbrella seals they will just sit on the valve stem and go up and down with the valve. I used comp cam seals with a .456 lift can and it burned a lot of oil. Switched to I THINK it was sealed power brand seals as they were longer and it no longer burns oil.