Engine: valve stem seals

[rocket1]

I'm contemplating replacing the valve stem seals on my 57 Commander,I will pressurise the cylinder to remove the valve springs so that the valve does not drop.Has anybody had experience in this matter and are the seals just o rings or umbrellas? Thanks in advance,Frank.

[r1lark]

I'm contemplating replacing the valve stem seals on my 57 Commander,I will pressurise the cylinder to remove the valve springs so that the valve does not drop.Has anybody had experience in this matter and are the seals just o rings or umbrellas? Thanks in advance,Frank.

The original valve stem seals were the umbrella type. But after almost 65 years, they may have been changed at some point to a different design.

[JoeHall]

I always use umbrella seals

[StudeRich]

You will know if someone has machined the Valve Guides to install Perfect Circle (Perfect Seals"?) Teflon Seals that many have said wear the Guides excessively from being TOO dry. You will SEE that easily.

There are however "Other" Valve Seals available now. The High Temp. Valve Seals for the Mustang and Thunderbird Turbo Coupe 4 Cyl. Engine is one, it just slips onto the Valve Stem as the Stock Umbrella Seals did.

Also there is really nothing wrong with the Original Seals, except they do not last way longer than designed for, like 50-60 YEARS that people run them!

[Flashback]

I'm contemplating replacing the valve stem seals on my 57 Commander,I will pressurise the cylinder to remove the valve springs so that the valve does not drop.Has anybody had experience in this matter and are the seals just o rings or umbrellas? Thanks in advance,Frank.

I have replaced valve stem seals this way. I am sure you already know, just a reminder, be sure the piston is up on the cylinder you are replacing seals on. The information already stated on seals is right on.

[Mike Van Veghten]

Since no one's answered half of your question, I'll try.

Yes...you can use air pressure to hold the valve in place as long as the seat and valve form a good seal..! Beware the exhaust side. If you do not have hard seats, you may find that the exhaust may leak. But sure, give it a try.
Lock the crank from moving and put the piston at the top of its position, then pressurize the cylinder. This way, IF...you happen to drop a valve, you won't lose the valve into the cylinder if the piston is all the way down in the cylinder.

OR, as some do, again, put the piston "near" (not exactly) the top of the cylinder. Stuff some nylon rope into the cylinder thru the spark plug hole. Push it in fully with a screwdriver to keep the valve in a good position. The valve may drop a little as you break the lock loose, that's ok, it's not going anywhere where you can't easily retrieve it.

As far as seals go, all that's been said above.
Modern umbrella seals (11/32" dia) will work fine, no need to go into anything fancy / expensive...NO MATTER how the guides may or may not have been machined in the past.
Don't worry about any doomsday comments.

Remember to pick out any broken pieces of old seal if they do break into pieces from being old and hard, before you put each valve/spring/seal/retainers back together.

Have fun...go slowly, don't drop anything into a nonrefundable location..!

Mike

[JoeHall]

I agree with Mike, and prefer the rope trick, with rope around 1/4" diameter. I feed about 6' of the rope in while at/near BDC, then rotate the motor till the piston begins to squish the rope. I break each piston's two valve collars loose just before rotating the engine to squish the rope. To rotate the motor, I use a socket on the alternator pulley nut, and squeeze the belt together with my fingers tight enough to not slip on the crank pulley.

[dpson]

I've had good luck reducing oil burning, especially on start up, by using Ford 140 & 302 engine valve seals used on cars built July 1986 to 1992.

Fel-Pro SS 72683. You'll need two sets.

They slip on ( the set includes a plastic sleeve you slip over the end of the valve to prevent damage to the seal during installation), no need to machine the valve guides.

[Charlie D]

The valves in my 259 had been machined for the Teflon seals. When the machinist put the heads back together he used Teflon seals on the intake valves and umbrella seals on the exhaust. He mentioned something similar to what StudeRich has already said. He thought it was more prevalent with the exhaust valves.

[JoeHall]

The valves in my 259 had been machined for the Teflon seals. When the machinist put the heads back together he used Teflon seals on the intake valves and umbrella seals on the exhaust. He mentioned something similar to what StudeRich has already said. He thought it was more prevalent with the exhaust valves.

I do not see how it is possible for them to wear the guides excessively, since only the valve stem wears against the guides. But I certainly see how they can wear the valve stems excessively, almost to the point of premature valve float, till they wear in. I was warned of the excessive stem wear by my favorite machinist / engine rebuilder out in California over 30 years ago, and till now, I heed his warning.

[StudeRich]

I do not see how it is possible for them to wear the guides excessively, since only the valve stem wears against the guides. But I certainly see how they can wear the valve stems excessively, /Cut/

No Joe, it is not the Teflon causing wear on the Guides, it is the lack of sufficient OIL, that causes the wear on the softer cast iron, the Guides, not the Valve Stems, at least not excessively.

[DieselJim]

I have every thing made up to change the valve guide seals with the heads on the car. Your profile does not have your location so we do not know where you are.

[doofus]

Rocket1, while you are changing stem seals clear out the drain back hole, dip stick works nicely there! Luck Doofus

[JoeHall]

No Joe, it is not the Teflon causing wear on the Guides, it is the lack of sufficient OIL, that causes the wear on the softer cast iron, the Guides, not the Valve Stems, at least not excessively.

Cast iron guides do not wear due to lack of lubrication, they wear because they are (soft) cast iron. Oil is not supposed to get down into the guide on exhaust valves because the heat will turn it into carbon, which eventually sticks the valves. Carbonization is a non issue with intake valves, but if not sealed properly, the motor will suck enough oil into the combustion chamber to foul the spark plugs. It is unwise to replace worn out cast iron guides with new cast iron guides because you can sleeve them with bronze. The 56J heads have non-removable guides, and that's a good thing, because there's only one option, and that is to install bronze sleeves. The bronze will last forever. Put another way, regardless of which oil seal is used, oil is not supposed to get into the valve guides.

Recalling the lecture I got from the engineerings rebuilder in California, the nylon seals would grip the valve stems so tight they'd actually wear the stems down. Then, the motor would start burning oil, because the nylon did not have elasticity enough to stay sealed around the stem. I have always used umbrella seals, so have no first hand experience with nylon seals, only know what he told me.