rocker arms felt wicks on giving my mk 4 a valve adjustment i noticed that while the push rod area was well lubricated the tops of the valves didnotyes they where moist and a oily film but i expected to see the collett part othe valve with some oil present when the engine was rebuilt some 8000 miles ago the wicks where reconditionednew every thing has been checked clearances first time since engine was built nowear but iam concerned about what i think to be lack of oil passing through rocker armsinto the wicks big 4 peter
Hi Peter,
Run the engine with the rocker cover removed so that you can see where the oil is going. As you know it is fed from the rear shaft pillar travels along the centre of the shaft and exits at each rocker. If your rocker bushes are a bit slack then the oil could be exiting out the sides of the rockers. The bushes themselves need to be drilled (or are split in the middle) so as to connect with the wick channels. It would be worth checking.
Peter
The wicks are made of engineers felt [ a white felt made for this purpose ]
It needs to be replaced as over the years it has acted like a filter for the oil passing through , And eventually it gets blocked and has the consistency of pencil lead . And so no oil gets to the valve stem .
The old wicks often need to be drilled out.
The tappet adj screws often need to be replaced as when they we hardened , the whole screw was done . the ball, good , but the thread… the threads are so fine that they tended to through harden, and so become brittle
Years ago I had abatch done but only had the ball hardened. laving the thread { 5/16" Cycle thread . still tough but not brittle.
First, if you got 8,000 miles after the rebuild and no sign of wear, then it seems you start from a good position here.
Oil flow can be observed with the rocker cover off. Flow to valve ends and push rods can be seen. Original rocker shafts had 24 bushings so an open ring space between the bushings for each rocker could provide oil flow from shaft interior to the two feed points in the rockers. Original shafts also had a 2-3 thousandths flat milled at the shaft feed hole for each rocker, this flat provided oil flow for the bushings. Aftermarket rocker shafts may not have the same design, i.e. no flats.
Depending on the shaft and bushing designs used, adequate flow to valve ends and push rods needs to be assured. Felts inside the rockers clog over time.
I did this in May '08 with advice from this group.
I made my brass plugs 3/16" long so there would be something to grab with pliers, easier to get out next time.