[ROVERNET - UK] P6 interference/free running?

[Ron Venter]

Nathan and Vern,
                    You have me worried! I recently fitted a 2000 
engine with new 9:1 pistons. With the head off, the crankshaft 
rotated fully. With the head on but without the timing chain 
connected, I could not turn the crankshaft a full 360 
degrees  --  almost but not quite. With the timing chain on 
everything rotates smoothly. What have I done wrong? The engine is 
not yet back in the car, so I don't know if it actually runs.
                                                 Regards,
                                                         Ron V.

At 09:09 AM 07-12-09, you wrote:
>  I have
> > one question. What is
> > the difference of a free running design and a
> > interference design?
>
>A free running or free wheeling engine has enough
>clearance between the valves (when open) and the
>pistons (when at Top Dead Center) that they don't
>collide if the timing chain or belt fails and the
>valve timing gets out of sync.
>
>An interference engine can bend valves or worse if the
>chain/belt breaks.
>
>I believe the original P6 engine is free wheeling.
>
>Regards,
>
>Nathan
>
>
>
>
> 
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