I've been having issues with a bit of visible smoke after idling a few minutes. From what I have researched, the most likely cause is worn valve stem seals. Has anyone seen a write-up on this fix? I've been told that having compressed air shot into the spark plug hole will allow the valves to be accessed without removal of the head. Any thoughts or more likely condolences?

 

Condolences? Strange choice of word...

Yes is sounds like you have worn valve stem seals. The owners manual advises against letting the car sit idle. If you know that you are going to be sitting for a few minutes, turn the car off. Also, what weight oil are you using ? What climate are you located in?

I have replaced valve stem seals with the head off. I could NOT image doing it with the head on. If you are going to do it with it on, yes, you raise the piston, put air pressure or a rope in the cylinder spark plug hole, then work on changing the seal.

I use 10w-40 weight oil and have very little smoking. I only idle while sitting when allowing the turbo to cool down.

 

It is fairly common for professional mechanics to use the compressed air approach. But here's the deal.


1) You have to have good valves and you have to know how to tell if you don't
2) If the air supply craters unexpectedly you have an immediate issue and you have to prep for that.


If you 're willing to gamble n it, you will need the following as a minimum:
- something like a compression tester that you can attach compressed air.
- Valve spring removal tool
- small magnet
- rubber disk with a hold slightly smaller than the valve.
- basic tolls for getting to the parts and to take off and put back on
- Seals and gaskets required


To do an in-place seal replacement:
- You do 1 cylinder at a time (removal and install). You bring the piston to TDC so both valves are CLOSED
- Insert the adapter and apply air pressure to the cylinder CONTINUOUSLY. You probably only need a few lbs of air pressure. But keep in mind that the air will leak by the piston rings and valve leak-by, etc so you need a continuous air supply to keep the valve closed. Pull the dipstick loose so the air has a place to go.
- Using the valve spring tool... compress the valve spring slowly. Watch to see what happens to the valve itself. If it moves down with the compression, the valve is not secure and will drop into the cylinder when you take the keepers off. At that point you're screwed.
- If the valve stays put, use the magnet to remove the keepers. They have 1 or more grooves that lock them in so you need room for the spring washer to clear the keepers. Don't loose the keepers and keep them in order for the valve they came from.
- Slowly un-compress the spring being carful not to bump the valve. Remove the valve spring and washers.
- Slide the rubber disk over the valve stem. Don't push the valve down or the air pressure is gone. Essentially you are trying to add something to the stem so the valve can't fall down into the cylinder.
- Remove and install the sea 1 valve at a time. You will have to remove and re-add the rubber disk as you remove the old seal and add the new one. Hold the valve while its off so you don't drop it.


Notes:
-You are on your own for this one. It's risky if you are not careful...
-You drop the valve in the cylinder and the head has to come off to address that
-I don't know if the valve is long enough to fall to the piston with stem exposed. I don't suggest trying to find that out.
-Make sure you know how to dismantle AND install everything before you start. RSPI has a very good video on cam removal and install. Know how to time the engine
-This is not for the faint at heart. But if you do 1 cylinder COMPLETELY at a time and always work at TDC, you should be ok if you have mechanical aptitude