Valve stem seals worn ?

[GEMTA22]

Just like to know how to tell if your valve stem seals are worn ?
I heard its a common problem with 20v.

Is it black or white smoke ?


Thanks

[Nikkojoe]

Compression test.

1. Record the compression in each cylinder for a base value and CHECK with the manufactures recommended compression results.
2. If low or on the lower limit of the manufactures compression figures, add a small amount of oil into each cylinder and check compression
3. If there is a large increase in compression, then rings are gone.
4. If a small/minor increase, stem seals are worn.

But without that, generally if your engine blows smoke only after idling for a bit it will be valve stem seals (and sometimes a bit of top end to). Generally if under load, usually rings.

[adam]

Coast down a long hill. Make sure the car is still in gear so that you're using engine braking.

Stop at the end of the hill for a few seconds then take off like normal. Should give you a cloud of smoke. You could also see smoke pouring out the back during the engine brake, depends on your exhaust system as well.

[GEMTA22]

I did a compression test and it came out like max 2psi different across all pistons.
The motor is in good nick, you can tell while your driving.
It pulls really well and revs out past 8k no worries.

Just running rich i assume, the smoke is black.
Running a aftermarket ecu and going thru alot of petrol atm.

Worn rings usually have white smoke isnt that right ?
There was no white smoke.

[Nikkojoe]

Just sounds like its running rich :)

Get a tune

[Javal]

I did a compression test and it came out like max 2psi different across all pistons.
The motor is in good nick, you can tell while your driving.
It pulls really well and revs out past 8k no worries.

Just running rich i assume, the smoke is black.
Running a aftermarket ecu and going thru alot of petrol atm.

Worn rings usually have white smoke isnt that right ?
There was no white smoke.

Bluey smoke for blow-by and valvestem seals.

Nikkojoe: A dry/wet compression test isn't indicative of valve stem seal condition. You'd have to do a leak-down test to tell that. The Compression is always going to go up slightly on a wet test, as regardless of ring condition, it's going to seal better. ~5-10psi increase is normal.

[Javal]

Just sounds like its running rich :)

Get a tune

Also this.
Glad it's not major.

[GEMTA22]

Awesome thanks guys!!.

Really appreciate the input.
The comp test just reinforced my thoughts.

Getting a full tune on Wednesday.
If theres still smoke ill get the stem seals done.

[Nikkojoe]

Bluey smoke for blow-by and valvestem seals.

Nikkojoe: A dry/wet compression test isn't indicative of valve stem seal condition. You'd have to do a leak-down test to tell that. The Compression is always going to go up slightly on a wet test, as regardless of ring condition, it's going to seal better. ~5-10psi increase is normal.

In the past my method (which has been obtained from OTHER workshop manuals) has worked for me. It is important to know that if you have low compression to start with and you are using oil, it will be one or the other (providing its even low compression and not just in 1 or two cylinders - ie possibly bhg or bent valves).

[GEMTA22]

I got 183 on cylinder 1 and 185 psi across the other 3 dry test.

It went up evenly by 10 psi for the wet test.

Thats still in the specs for the motor.

[Javal]

I got 183 on cylinder 1 and 185 psi across the other 3 dry test.

It went up evenly by 10 psi for the wet test.

Thats still in the specs for the motor.

Those are good readings.

Nikkojoe: I was taught otherwise, but if your method of diagnosis by wet-test has worked for you, i'm not going to argue :)