1980 280 E M110 no oil pressure in camshafts
 

Please, I need some help trying to figure out why is not oil pressure in the camshafts in my 110 engine, the exhaust cam
is the worst one and make a terrible cliking noise the oil pressure gauge inside indicate full pressure when is cold and half way when is hot.

Does your engine have the drip tubes like all of the V-8's? If so the tubes are likely clogged or the oil passage in the rear most tower is clogged. With the valve cover off and the coil wire disconnected you can spin the engine over with the starter. This will build enough oil pressure to see if the drip tubes are flowing. Another possibility is that you have already been under the valve cover and disturbed the drip tube. The plastic bits get brittle with age and break easily.

I wouldn't run the engine at all until you get oil flowing over the cams.

I can't think of anything special except maybe one thing.

Originally the M110 cams had about seven bearing surfaces where they went through the head. Replacement cams did away with all those bearing surfaces (on the cam). This would leave a couple bearing journals in the head with no cam surface against them. I forget how we plugged the oil holes but if they ever got loose or weren't plugged when the cam went in it would sure reduce oil feed to the cams.

I have seen a few 280's at the mechanic in need of engine jobs - crank bearings shot. The mechanic believes its because the owner/previous owner was not real good about oil changes and these motors seem to be real fussy about that.

I have a same problem after overhauling entire engine. does your rocers spraying oil to camshaft?? Small hole at top of the each rocer.
I belive i have a loss of presure to cam cover, but i dont know from where.
Cover the chain and take oil can and run the engine and see if any lubrication is present.
let me know if you find your problem,,,,,,

Yup, I just went through this with a replacement head. Tap the open ports in the cam towers with a M6X1.0 thread and install an allen head screw. If you're lucky, the open port will be on the intake cam. You can slide the cam back, unbolt the offending cam housing, tap and plug or replace the loose plug (at the base of the housing where it mates with the cam box) and re-install.

No, it wouldn't show up as "low oil pressure" because it is after the gauge.

http://www.peachparts.com/shopforum/vintage-mercedes-forum/233438-weekend-wrenching-post2288083.html#post2288083

Let me amend the previous statement of "intake cam". It doesn't matter because you have to pull the housing completely off to plug the oil ports.