Timing chain tensioner problem

[Novamonte]

I am reassembling my engine after replacing the head gasket and have come to the point where the chain tensioner is to be reinstalled, but it won't work properly. I only get the pressure from the spring, but no oil pressure builds up when I pump the tensioner. I have even submerged it in oil and pumped it under the oil surface with the same result, and also filled it with oil before putting the cap on. All the parts are there and none of the holes in the tensioner, the piston or the little cap where the ball sits are clogged. Is there anyone out there with some ideas or should I just order a new one (they aren't cheap)?

[ja17]

These usually do not fail. Not really much to go wrong in them.  Make sure all the parts are assembled correctly.

[Novamonte]

Agree - the mechanism is simple enough and it is easy to understand how it works simply by looking at it. And your excellent photos on the technical manual made it clear to me that all parts were there and correctly assembled. After some further attempts I now understand the problem. I was pumping too fast, not letting the tensioner suck in the oil when decompressing, so the piston was just decompressing and compressong air. When releasing the pressure slowly the tensioner sucked in the oil and built up the hydraulic pressure.

[ja17]

Sounds good. I usually install it not primed. I fill the oil reservoir in the chain galley with oil, then pump the tensioner up by manually pumping  the chain tensioner  sprocket arm until the tensioner becomes firm.