Hi all,
Well, after removing the timing cover and finding the oil pump o.k., looked around for the relief valve behind the cover, not there, in fact it was accessable from outside the engine, if you knew where to look.
All covered in grime, so invisible to the untrained eye, was a circlip at the end of an oil gallery on the passenger side of the timing cover.
This removed, revealed a curious arrangement of spring and valve. The piston and spring did not mate well when the piston is in backwards!!! It took a few moments to analyse the gallery arrangements and flow patterns, and to realize the piston was made to recieve the spring from one direction only, not the one we found.
Also found a loose timing chain without any tensioner system.
Anyone know if this is normal ?
Cheers.

 

I believe the timing chain tensioner is operated by oil pressure thru a hydralic tensioner.
Mike