Valve Stem Seals

[Pez14sr]

Just a few questions on valve stem seals. Could anybody tell me what they do and how hard they are to change coz i think mine are shagged. Would the head have to be taken off to change them?? And what are the symptoms if the valve stem seals are gone? i have alot of smoke coming out of my exhaust when i put the peddle to the metal!!!!

Cheers,

[robb]

They are worth changing especially on an older car and are probably the culprit for the smoke....I take it you have to top it up every now and then :roll:.

They are easy to do, just need a valve clamp.

Take head off....
Use valve clamp to remove 1 valve at a time...
They will be the black dirty things under the spring, put the valve back in and move it around to see the seal move...
They come of with some persuasion from a screwdriver...
New ones will just pop on easy...
Rebuild valve...
Do all 1 by 1...
Put head back on.

[Pez14sr]

cheers mate. are the seals expensive to buy or cam u get a kit and just do the lot while u r there. im thinking of getting my engine recond. anyway so i mite just wait till ive got the $$$$ for that and get the whole lot done at once, a complete overhaul of the engine coz it done 93000 so i think it'll need it!!!

[_JH_]

you don't need to take the head off, but if you have smoke not just on startup then they're either very bad or it could always be something else so best to take the head off. do a compression test first if possible, as the results may come in handy when you have the head off trying to figure it out.

[robb]

I think I managed to decipher that into "do a compression test first as this will tell you if there are any leaks on any of the 4 cylinders. Thus providing some indications as to what may be causing an oil leak."

A compression test will have nothing to do with oil seals themselves though as the seals are on the other side of the valve from the chamber so a leak here would be on the valve seat.

Whatever you do there is to way to sort this without taking the head off, impossible.

[Stuart]

full gasket set from AV is about ?11+vat iirc

[_JH_]

sort this without taking the head off, impossible.

lol. I was refering to changing the stem seals without taking the head off if he is 100% sure thats the problem. obviously if it may be something else as well he'll have to take the head off, as I said.

I used to think there wasn't enough room on 8v small block vauxhall engines to do it without removing the head, but a mate of mine proved me wrong when he did it on a 1.3 last summer. turned out to be less work than doing it with the head off.

[robb]

How do you do it with the head on as you can't pressure the spring to remove collets, or is there another tool now, I would have thought the valve would be loose and therefore be a pig to keep closed to remove collets?

I have the head off as the head gasket went, fortunately the head is 99% flat, i.e. one spot will accept a size 6 (smallest I have) feeler guage so I put that down to my straight edge!

I am just changing them as it should be customary on older engines, old ones were brittle and broke up upon removal!

It is probably worth you (Pez14sr) changing all gaskets and seals in top end cos you only have to do it once (fingers crossed).

[_JH_]

basically you get a hose that fits to the compressor and screws into the spark plug hole, pressurise the chamber and it holds the valve closed. but its normally done if its just smoke on start up and theres only a small risk of any other problems. as i said, I agree about removing the head, as heavy smoke under load can be other things.