M30 timing chain tensioner piston...

[Rustam]

Does the piston have to be greased before installation?

[winfred]

i oil it up good before sticking it in

[Kalevera]

You're going to prime the tensioner in a bath of oil before starting the car, so it defeats the purpose.

best, whit

[Rustam]

You're going to prime the tensioner in a bath of oil before starting the car, so it defeats the purpose.

best, whit

Thank you Whit.

[Rustam]

There is a minimal space between the piston and its cylinder housing. The oil goes through this space slowly, and is meant to go slowly by design.

Why?

The principle is same as that of shock absorber (it is in fact a shock absorber). The combination of "piston - spring - bypassing oil" serves to dampen the oscillation of the chain tensioner, after throttle is released... So unless one is weary of the possibility of chain tensioner oscillating for some few times while the piston goes up and down relatively freely (tensioner breaking risk), for the matter of absence of oil in the back of it, one should ensure that the cylinder is primed.

To prime the cylinder the piston must be pushed a few times manually so oil can bypass to the back of it.