Craigorypeck

Took the cam cover off to change cam bearings and after a day the head has completely drained back to the sump, is this normal? I thought there was an anti drain valve to stop this from happening.. It's the ball bearing that was rattling around when I was working on the head I presume... any thoughts peeps??

tabetha

There is NOTHING to stop the oil from draining from the head area to the sump, it needs to, there is a big hole at the rear where the oil goes back and there is no restriction/valve.
The only "anti drain" so to speak on the head is in each tappet, so in theory they hold the pressure so keeping the contact so they don't rattle, in practice most take a few seconds to pump up each day, a lot more so when old.
tabetha

Craigorypeck

Whats this mean? Taken from a cosworth workshop manual..


The oil gallery of the cylinder head is fitted with a non-return valve which eliminates oil drain back after the engine is switched off
When starting the engine the anti-drain back valve opens for immediate lubrication of the camshaft journals and hydraulic tappets.

Anti-drain back valve in cylinder head
1 = Ball in closed position (engine switched off)
2 = Cross drilling
3 = Cylinder head bolt drilling (oil gallery)
4 = Main oil gallery

Anti-drain back valve in cylinder head
1 = Ball in open position (with engine in operation)
2 = Direction of oil flow

The cylinder head gasket differs from the standard OHC gasket in that it has revised openings to match the Cosworth cylinder head.

tabetha

I forgot about the supply side, it will likely have a valve, there is also a valve fitted inside each oil filter for the same reason, sorry for the confusion.
tabetha

Craigorypeck

No worries.. all is well then I think.