Does this mean I have a bad piston ring?

[JeffMoore64]

From a prior thread where I had a bad welsh plug, I removed the manifold and took a peek at the valves. It looks to me like the left valve in the picture is oily. If that is true then I think I might have a bad piston valve. Car runs, well it did until I took the manifold off, so should I care if it is oily? I really don't feel like pulling the engine all apart.

IMG_0170_400x300.jpg (187.28 KiB) Viewed 6248 times

[Steve Simmons]

Probably a bit of oil getting down the valve guide. If the valve still moves freely and seals well then I wouldn't worry too much about it. You could try running a bit of Sea Foam through it. That stuff actually works pretty well.

If the valve isn't sealing then I'd pull the head and have the valves done and flatness checked, then re-install. IF it's leaky then the head job could make a big difference in performance.

[stephen stierman]

If the car runs well and doesn't use huge amounts of oil, I wouldn't worry about it, unless you drive it 10,000 miles a year.
What you can do is install umbrella type valve seals on the valves which may keep some of the oil from running down the valve stems. This can be done without taking the head off. I did it to TC2911 and it was helpful in stopping the blue smoke on start up and lowered consumption slightly.

[JeffMoore64]

Again thanks for the replies,

Steve,
I bought some Sea Foam and was told you need to run the engine when introducing it. It was suggested to introduce it via a vacuum line, which I'm pretty sure the MG doesn't have. Any ideas on how to introduce it without putting it into the tank?

Stephen,
Are these umbrella type valve seals available from Moss? If not where would I get them? Just like to know if I decide to do that further down the road.

All,
Anyone have further thoughts on the use of Sea Foam?

TIA,

Jeff

[stephen stierman]

Felpro part #70373, I believe this may be a standard Ford seal and are available from any parts source, probably not Moss.

As far as Seafoam, not to dis Steve, but I am just not a believer and would not run it through my 70 year old engine. I am not sure what roll it is supposed to play in a TC engine....for sure I don't want any of it blowing by the rings and running down into the sump and through the bearings.

[Duncan M]

Stephen, are you saying that you use those in place of the standard rubber seals?

Seafoam is peddled as a fuel stabilizer for ethanol fuels. I doubt it does anything that gasoline cannot do, as far as cleaning anything out.

Jeff, a fresh tank of gas and an oil change would do wonders for the engine, along with a long drive. When you get back from the long drive drain the transmission and differential oil while still hot.

[stephen stierman]

Duncan, yes I have installed them about five years ago. I rather got tired of a blue cloud upon hot start up.
Steve

[Marv]

I use the umbrella seals as well on all of my rebuilds but I also use the original o-ring seals at the cotters as well per normal build. On the advice of a much more seasoned and experienced mechanic than myself, i take an exacto knife and cut a 1/16th inch slit in 4 places 90 degrees apart on the umbrella skirt. That insures that the valve stems will get a minimal yet adequate amount of oiling. I run the bronze manganese valve guides as well. No problems with hot start or clutch shifting with blue smoke clouds.

Always have my trusty garage buddy close by!!!

[stephen stierman]

As I recall, and it has been awhile since I installed those seals, they do not firmly slide over the top of the valve stem and stay there blocking out all oil, fumes and such, but from what I have seen they do stop a fair amount of oil from dripping down the stem and guide into the cylinder.

[ian theobald]

Love your garage helper.
When I was a young teenager we had a lovely white Poodle .Often I would be fixing my bicycle or someone elses and get oily hands .
I would get dry washing powder and wash hands under the tap and call the faithfull dog and use him as a towel.
My mother caught me in the act and gave me a hefty whack and told not to do it again.
Poor dog only thought it was getting love and attention.
As for oil on valve it probably is only oil seeping down the valve guide .
Most of us would never see inside but look at any BMW motor bike on start up where the oil has weeped down the valve stem or better still check out a Lockheed Super Constellation 4 x18 cylinder on start up.
I live near an Historic Air Museum several hrs south of Sydney which has one such plane in its collection.
They don't seem to mind a bit of oil and fuel out the pipes on start up.
My TC puffs a bit of smoke down long mountain descents but uses bugger all oil so not worried and never seems to any other time.
One thing that is important though theses days is upper cylinder lubricant [ash less oil ] with all this unleaded petrol and reckon a bit of oil down guides might prevent a sticking valve.
Had this happen on my 2 1/2 ltr riley .Luckily did not damage piston or valve

[Steve Simmons]

I don't put Sea Foam into the intakes, I put it in the fuel tank. It helps to remove gunk from the pistons and valves. I don't believe in these kind of things either, but this is the one exception because I've personally seen it work. A relative had a 250K mile Jeep that wouldn't pass its emissions test. We poured a bottle into the tank, ran through that tank, then did it a second time. On the third fillup with clean gas, the Jeep passed the test with flying colors, and it was running better. I've also used it on my MGC which had leaky valves due to carbon buildup. After one bottle, compression was up and the leak down test showed big improvements.

Some people swear by putting it into the intakes for cleaning pistons but I've never done it myself. And while they say you can add it to oil, I would NEVER do that. Way too scary for me.

[Duncan M]

Marv brings up the subject of valve stem to guide lubrication. A basic distinction on the sort of modern "umbrella" seals is if they run up and down with the valve stem or not. "Deflector" generally means it goes up and down, while "posi" means it stays put on top of valve guide. "Umbrella" vaguely might mean either one. See 1st pic here- http://www.felpro.com/technical/tecblog ... seals.html

Moss sells what they call an umbrella seal, but I understand it is actually a posi seal, which will fit XPAG --and to be used once the original metallic deflector is removed. Sold as a seal on 948cc 1098cc and 1275. Note they say (where used) that on the 1275 it is for intake only.
https://mossmotors.com/seal-valve-stem-umbrella

The XPAG came with its own metallic valve stem oil deflector, along with the little round rubber seal. This (original) arrangement, or the modern rubber (up and down) deflector, would seem to pose no threat to exhaust valves, as it allows for some oil mist for lubrication. Marv discussed cutting slits to achieve this lube in a "posi" type seal.

The controversy of if or if not the "positive" type seals should be used on exhaust valves shows up in many articles on the XPAG that state two opposite viewpoints. One side says never use a posi seal on exhausts, and other side says go ahead and do it.

Don't do it: http://www.mgccyregister.co.uk/technica ... day-eight/

Do it: http://www.ttalk.info/StaffordSeal.htm

Unfortunately, neither of these articles gives too much specific info on that type of guide material (bronze or steel) are used, or what material the exhaust valves are made of, i.e. SS or standard. They both say to remove the original metallic deflector when using the posi seals. Interesting all the stories we have heard of SS exhaust valves used with bronze guides (sounds great) that fail. MY guess is the fail is from using posi seals on exhaust, or using posi seals on exhaust that have no slits cut into them, as Marv discussed above.

Stephen mentioned he no longer sees blue smoke on hot starts, which indicates he has installed posi seals on the exhaust valves, with no slits.

[stephen stierman]

Duncan, the Felpro seals that I have installed do not "lock" onto the top of the valve guide on a TC so likely do move around with the valve rather than wiping oil off, thus not preventing lubrication to the stem and guide. Now these as I recall were for small block Fords and perhaps other American cars and may very well be used as posi. seals on those cars, but do not fit as such on a TC unless some machined modifications were made to the top of the guide. My belief is that they do act as an umbrella and simply keep oil from running down the stem through the guide particularly when the engine is hot and not running. There is plenty of oil splashing around as well as an oil mist under that valve cover so I am quite sure lubrication is getting where it needs to go. As far as not seeing a blue cloud there still might be some blue smoke but it is not as evident from the driver's seat as it once was.

[Duncan M]

Thanks for clarifying Stephen. Did you keep the original stock metallic "oil deflector" in place? There are those that insist the exhaust (and intake) valve guides on the XPAG can and should be sealed up with the locking or posi type seals. I find it a bit difficult to see why such sealing on the exhaust valve guides could ever be a good idea in this engine.

[stephen stierman]

Duncan, the deflectors are removed as they are in the way of the new seal.