Valve seals

[Elvis'dart]

replaced the umbrella valve seals when I pulled the head. Was very careful and put them on the correct valve. Fel pro seals. Car is burning oil. Lots of smoke on start up. Only 50k on engine. Pulled valve cover and seals are not sealing. They are sticking on the valve and coming to the top. Carefully pushed them down and they immediately go back up when I start the engine.

The valves are not varnished up. 74 225

Is there a break in period? Have put about 500 miles since I pulled the head.

Wisdom is appreciated. Will post in slant six forum too, sorry if you read this twice and if you have the answer Thank you!

 

[66fs]

Use the positive Viton seals from a V8. They "grip" the guide, intakes only.

 

[Elvis'dart]

Thanks for the reply. All 12 are not seating and I am not sure where to dig in next. Really dont want to pull the head again and replace valves and I don't think they are the problem.

 

[slantsixdan]

The umbrella seals are just that: umbrellas. Their job is to keep too much oil from "raining" onto the valve stem/guide junction, while still allowing enough to keep the stem lubricated (which the positive seals won't do—and remember, every Slant-6 ever built came with umbrella seals that were entirely adequate, with no smoke on startup).

The umbrellas are going to ride up like that; that's what they do. It's not a fault; they're working normally. It doesn't mean they "aren't seating", and there is no break-in period on them.

Assuming the head was rebuilt properly (what was done with the valve guides?), I don't think your problem is defective valve stem seals. Did this big smoke on startup just begin recently, or just got worse recently, or...? Does the smoke go away completely once the engine's warm? Or is it runtime-based, and if you warm up the engine, let it sit for a couple hours and then start it again (engine still warm), do you get a bunch of smoke again?

 

[66fs]

The umbrella seals are just that: umbrellas. Their job is to keep too much oil from "raining" onto the valve stem/guide junction, while still allowing enough to keep the stem lubricated (which the positive seals won't do—and remember, every Slant-6 ever built came with umbrella seals that were entirely adequate, with no smoke on startup)...

OEM positive seals, that grip the guide do allow oil to lube the stem. Have to agree with the rest you said. What kind of oil are you using? Time for a compression check or leakdown test.

 

[nm9stheham]

The umbrella seal info is right on. Before any more testing or work, answering Dan's questions on more detail about the oil burning is needed. Is this just on startup? Has the can been driven recently? Was it doing this before the head was pulled? Was the head reworked, including the valve guides, or was it just cleaned up and the seals replaced?

 

[BillGrissom]

Ditto. Bad stem seals allow the high intake vacuum at idle to suck oil past the stem. You will see this after idling a long time, then accelerating. There is always a little oil flow by design. Indeed, if totally dry the valve stems and guides would wear. Dan is right that the umbrella seals are not designed to lock on the guides like you imagine. The "racing" type do, but you must machine the head to fit those.

But, it only takes a few drops of oil to make massive smoke. I had this in my 82 Dodge Aries 2.2L. It would fog a certain intersection like the mosquito foggers of FL when I was a child. That was after idling 5 min at a stoplight, facing uphill (affected how the oil pooled?). I finally found it was because I had installed the plastic PCV snorkle facing down, but that let the cam sling oil up into it. It was supposed to face upward to draw oil-free air from just below the valve cover. I realized that after wondering why the elbow had a drain slit. I later found it stated in a racing book. I imagine many Chrysler cars & minivans were condemned with "bad rings" for that simple error. Similarly, anything wrong in your PCV system could suck a few oil drops, such as an after-market valve cover without a baffle (many need a special rubber baffle insert). My M-B diesels have an oil-separator in the PCV plumbing, as do many current Jap engines, expecially those w/ a turbo.

 

[slantsixdan]

an after-market valve cover without a baffle

That's a good point. The chrome valve cover-shaped trinkets from China have no baffles, and neither do the Offenhauser cast aluminum covers, and I don't think the Clifford covers do either, though I could be wrong on that. This page makes interesting reading for anyone fixing to install baffles in e.g. the Offy aluminum valve cover. The site belongs to a company selling an adjustable/tunable PCV valve for $129 (yes, you read that price right). It's an interesting idea the vast majority of us probably would not benefit from. But the baffle article is worth a read.