Oil On Plugs

[Guest DAVE1954]

Hi I posted a topic yesterday,I had oily plugs on my pinto engine so I thought valves or lower end trouble, so I posted topic, enquiring if changing engine from 1.6 to. 2l was straight swap, which I really don't want to do at this point. Since yesterday I cadged a compression tester ,and compression is about 175 psi on each cylinder. Could the oily plugs be anything to do with the breather system ( pulling some oil into the inlet manifold. Cheers. Dave.

[Guest zerorace]

valve stem oil seals could be the cause.

Edited July 14, 2015 by zerorace

[cb750]

As above, valve stem oil seals or badly worn guides taking the seals out. Got a Ford Capri cheap because of this, seller thought he had broken piston rings (wish I'd still got it!)

 

[Guest DAVE1954]

Hi I thought with excellent compression, valve stems or seals would make a bad compression test, the guy I bought this part built car off said the car had only done 26 k which shows on the donar clock,the engine is very quite, and smooth.thats Wye I hought it might be something wrong with breather system. Cheers

[kevin the chicken]

Valve stem oil seals that are worn quite often show up with a cloud of blue oil smoke when the engine is started after being sat for a little while as the oil has had time to run in to the cylinders from the head. The smoke clears as the engine warms up and burns the oil away.

[Guest DAVE1954]

Thanks for all the replies, regarding blue smoke, i don't get any hot or cold, but every time I've taken the plugs out they've been a bit wet and oily. Cheers

[megadodo]

Age hardened valve oil seals, won't affect compression at all but will let oil into the combustion chamber especially on the over-run.

[stevedohc2b]

The valves seal the combustion chamber.

The stem seals are above this in the valve guides in the head so can not affect a compression test. Oil is pumped to the head to lube the cam and return to the sump through oil ways. Worn stem seals let it seap to the back of the valve and enter the combustion chamber when inlet valves open or is pushed out of exhust when exhust open.

 

Hope this helps

 

Stephen

Edited July 15, 2015 by stevedohc2b

[Guest DAVE1954]

Thanks again, great replies, it makes sense to me now that it is valve seals, although engine milage is very low the car ways idle for many years. Now no problem just relieved it's not bottom end. Dave

[Guest zerorace]

If you take the rocker cover off you will be able to see the valve stem seals if you have a look at them you may see small cracks round the valve stem where they have age hardened it is a age thing not mileage.

[Guest 2b cruising]

Any fluid even a small amount would give you a higher compression reading. The oil helps the piston rings to seal giving a higher reading. Hence wet and dry test to determine cause of compression loss. If a wet test ups the reading from the dry test, I would surest faulty piston rings. If the wet test stays the same it points to valve burn out, or cracked head, blown gasket ect.

 

With regards to yours, has it been out on the road yet and often used. If not, I would ignore your readings for now until such time it has done a few miles to get things back to normal. The wetness could be a number of things, ie rich mixture from cold starts or even condensation after starting from cold so many times.i would suggest there is no need to worry at this point.

 

If however you are using your car, with all readings being identical, I would suggest rich mixture settings or possibly valve stem seals. To check this, after being on over run down hill, your engine creates a larger than normal amount of vacuum due to your throttle being closed. because your cylinders cannot get the air, they pull in whatever they can through wherever they can, ie sump, breather system, but most commonly valve seals. Normally a faulty breather system, or faulty rings would smoke continually. Faulty stem seals or valve guides would most commonly only smoke immediately after over run, then clear when running normally. Watch your mirror, if after over run you get a quick puff of oil smoke which clears after a couple of seconds, it would point to stem seals or valve guide wear.

However, as stated earlier, you will not get normal running conditions if your engine has been stood for a period. A run in period should be given to let things settle and get back to normal first. If mileage is correct, it would be unusual for it to be faulty.

[Grim]

regardless of any other issues, i'd always recommend people check their breather setup. Either remove the contents of the PCV valve and vent to a tank or atmosphere, or fit a new / cleaned pcv and feet to inlet as originally intended

[agent_zed]

It is possible to change stem seals without removing the head. never tried it but you can put rope into the cylinder through the spark plug holes and then turn the engine to lock the piston against the valve. you can then compress the valve spring and remove the seal and replace.

 

I had worn stem seals and as above would get a smokey start. I had the head off though so removed the valves and they had a lot of burnt on oil that i had to wet and dry off.

 

hth