Had oil on top of number one piston so I took head off replaced valve stem oil seals put head back on with new head gasket done a few miles checked again and still have the oil issue, actually looks to be worse now... not just speckles but a complete mirror reflection bout a mm deep in the middle of the raised top.. This would defo suggest its coming from above if its on the raised crown?
The other 3 are dry and look normal
All cylinders have 130 psi compression so the rings are OK??
Any ideas what I should do next?
Head was pressure tested, does this only test the water jacket for leaks?
NA cosworth BTW
Cant really tell if its smoking much and at what point cause I only get to try at nite after work in the dark...!
Thanks in advance for your help.

[Edited on 22/2/11 by Craigorypeck]

as a stab in the dark with out seeing it i would say the oil scraper ring as it wont lose you any compression but will allow oil up onto the crown. what did the head look like when you had it off were the valves clean or caked up?

What engine? 130psi is very low for a modern engine.

Are you certain the oil didn't get there when you removed the head?

The valves were black and a bit crusty...

Engine was cold when checking the psi. But with a CR of 10.8:1 on a YB I was expecting quite a bit more. I have a cheapo sealey gauge that may be giving a dodgy result.

All rings are new and properly gapped bout 200 miles ago..

Anything I should check before taking the head off again??

quote:

---

Originally posted by MikeRJ
Are you certain the oil didn't get there when you removed the head?

---

The rings won't be bedded in but 130psi is very low more like what you would expect from a clapped out Xflo.

You did have the throttles fully open and all the other spark plugs removed when you did the test?

Throttle fully open, but plugs were in the other cylinders... I also have a reduction geared starter which does turn over way slower compared to the pinto one. Would that also contribute to a low reading maybe?

I had that problem on a zetec, It was lowish mileage and appeared to all be ok but used lots of oil.I changed the valve stem seals and it still used oil and the tops of the pistons were wet, all I could put it down to was faulty oil control rings but that didn't explain why the top of the pistons were wet.Eventually I gave up and changed the engine but thats cheaper to do with a zetec than a cossy engine.
Paul

I called the engineers who pressure tested the head and honed the block... He said all valve guides were within acceptable tolerances and evenly worn across the head so he suggested that an oil would be coming up ways and a ring may have snapped.
Bleedin 'ell, I never get to drive the beast!
Might go for the cross member off and the block supported from the top to get the sump off and take out the piston out.


ashg I think your right.. Ta

[Edited on 22/2/11 by Craigorypeck]

Heres what it looks like with the head off...

I couldn't resist- so there are a few finger marks on the crown.

Substance smells like petrol and oil mixed together.

comments welcome

Have the bores actually been honed? They look very shiny, or is it an optical illusion?

Bores need to have a quite rough but even finish for rings to bed in.

The flash makes them look shiney but they were honed..