It's Not The Car It Used To Be.....

[Dr H]

Christ! They are well a truly buggered.....

 

What could have caused that to happen on just one cylinder?

[Martin R]

Piston, valve interface is the term i believe? On the bright side the valves are still attached.

[Dr H]

Piston, valve interface is the term i believe? On the bright side the valves are still attached.

 

Yeah I know that! What I meant was what has given way to cause it on just one cylinder. Obviously not a cam belt / chain slip. Something failed in the piston / rod?

[danwebster]

Most likely valve cap or spring, possibly the tip of the valve. Do you know what poundage the valve springs are?

One of the above coupled with rpm I should add.

[jonnyfox]

Yes, Frank reckons cam timing but I'm with you Dan.

[danwebster]

Actually, looking at the picture again he's probably right...both the valves have twatted the piston. I wonder what kind of clearance they were running.

[jonnyfox]

Did the head of the valve fall off the stem, the stem is straight, the other stem is bent with the head still attached....

 

 

[Alex B]

looks messy jonny.
will the s1 be taking a trip to Le Mans?

[jonnyfox]

No Alex, I've called it a day on Le Mans.

[danwebster]

Yep you've pulled the head of the valve - hence me asking what poundage your valve springs are. If you run loads of revs and monster springs this is exactly the kind of issue you risk. I'm sorry to say that you need better quality valves than you're currently running.....give me a call if you want a chat about any of it...I have some experience of the ones you pictured previously. 

[jonnyfox]

Will do Dan as soon as the breakdowns complete mate