Replacing valve stem seals on S2000 on south coast.

[zz000mm]

Hi all,

I have an 2008 S2000 that has done about 205K miles.

It's starting to smoke, which I think is either valve stem seals or piston rings.

Advice on how to tell would be gratefully received.

Car has been well looked after and has been fully Honda dealer serviced all its life. I've owned it from 10K miles.

If it's piston rings, the simplest thing is a used engine swap.

I was hoping it just needs valve stem seals, so was going to give that a shot first.

Anyone have any recommendations for someone to replace the valve stem seals near Chichester in West Sussex?

Thanks

Brian
Chichester, West Sussex.

[paddy1970]

To help differentiate between valve stem seals and piston rings, here are a few indicators:

Valve Stem Seals: If the smoke is most noticeable on cold starts, or when you first accelerate after decelerating, this points to worn valve stem seals. The oil seeps into the combustion chamber overnight or during idle, causing smoke when the car is started or revved.

Piston Rings: If the smoke is constant, especially under acceleration or heavy load, it could be the piston rings allowing oil to burn during regular driving. Blue smoke under hard acceleration typically indicates worn rings.

Before making any decisions, it would be worth conducting a compression test or a leak-down test. These tests can help pinpoint the issue by checking for loss of compression (indicative of worn rings) or specific areas where the engine is losing pressure.

[Niglebick]

We have a high mileage s2000 (200,000+) just along the road, near Arundel.

Tom Gant ( TGM Racing) just outside Fleet is the man to go too. What he doesn’t know about s2000 isn’t worth knowing.
It’s a schlep, but well advised.

[zz000mm]

paddy1970 said:

To help differentiate between valve stem seals and piston rings, here are a few indicators:

Valve Stem Seals: If the smoke is most noticeable on cold starts, or when you first accelerate after decelerating, this points to worn valve stem seals. The oil seeps into the combustion chamber overnight or during idle, causing smoke when the car is started or revved.

Piston Rings: If the smoke is constant, especially under acceleration or heavy load, it could be the piston rings allowing oil to burn during regular driving. Blue smoke under hard acceleration typically indicates worn rings.

Before making any decisions, it would be worth conducting a compression test or a leak-down test. These tests can help pinpoint the issue by checking for loss of compression (indicative of worn rings) or specific areas where the engine is losing pressure.

Hi Paddy,

Thank you for taking the time to reply. I appreciate your help.

I have just had a compression test carried out.

1 - 160 psi
2 - 160 psi
3 - 165 psi
4 - 165 psi.

Values are low, but that could be simply down to the testing apparatus they used.

Values are very close, which looks good.

Car is definitely smoking though.

So could be oil scrapper rings or valve stem seals.

Kind regards
Brian. Chichester

[zz000mm]

Niglebick said:

We have a high mileage s2000 (200,000+) just along the road, near Arundel.

Tom Gant ( TGM Racing) just outside Fleet is the man to go too. What he doesn’t know about s2000 isn’t worth knowing.
It’s a schlep, but well advised.

Thanks Niglebick,

Your just up the road. My S2000 is red, silver wheels....

I dropped into TGM and spoke to Tom about nine months ago.

He was not that concerned about the smoke. Said I could look for a second hand engine and he could install it if it was loosing more than a litre every thousand miles.

I dont know how much it is loosing, but its enough to annoy cars behind at traffic lights etc.

TGM are the experts, so I would get them to do what ever I work out is needed.

Thanks for your help.

[SlimJim16v]

zz000mm said:

I have just had a compression test carried out.

It doesn't look like another test was done with oil squirted in the bores.

[zz000mm]

SlimJim16v said:

It doesn't look like another test was done with oil squirted in the bores.

Hi Slim,

What does the second test tell you?

Kind regards

Brian

[paddy1970]

The compression test results you provided—though slightly on the low side—are indeed very consistent, which is a positive sign. This consistency typically rules out significant wear or damage to the primary compression rings or cylinder walls. Since the car is still smoking, the two most likely causes remain valve stem seals or oil control rings (oil scraper rings).

The next step should be to check for stuck oil control rings. A soak with a product like Marvel Mystery Oil or Seafoam in each cylinder (via the spark plug holes) can sometimes free up stuck oil rings. After soaking, crank the engine (with the plugs removed) to expel excess fluid, then perform another compression test for comparison.

Then inspect the PCV valve. A malfunctioning PCV valve can create excess pressure in the crankcase, forcing oil past the rings or seals. Given its low cost, replacement is a good precaution.

If the smoking persists and you are leaning towards valve stem seals, replacing them is worth a shot. It is less invasive than rebuilding or swapping the engine.

[zz000mm]

paddy1970 said:

The compression test results you provided—though slightly on the low side—are indeed very consistent, which is a positive sign. This consistency typically rules out significant wear or damage to the primary compression rings or cylinder walls. Since the car is still smoking, the two most likely causes remain valve stem seals or oil control rings (oil scraper rings).

The next step should be to check for stuck oil control rings. A soak with a product like Marvel Mystery Oil or Seafoam in each cylinder (via the spark plug holes) can sometimes free up stuck oil rings. After soaking, crank the engine (with the plugs removed) to expel excess fluid, then perform another compression test for comparison.

Then inspect the PCV valve. A malfunctioning PCV valve can create excess pressure in the crankcase, forcing oil past the rings or seals. Given its low cost, replacement is a good precaution.

If the smoking persists and you are leaning towards valve stem seals, replacing them is worth a shot. It is less invasive than rebuilding or swapping the engine.

Thanks Paddy.

I had the PCV valve changed when I first noticed smoke.

I'll try a good soak and see where that takes me.

Thanks again Paddy

[SlimJim16v]

zz000mm said:

Hi Slim,

What does the second test tell you?

Kind regards

Brian

The oil helps the rings seal, so if the readings increase it tells you they're the issue. If no change it's the valves.
A leak down test is better though.