w115 220 oil pressure/circulation

I have a w115 220 which has done about 60,000 kms... I brought it with a siezed engine which had recently had a timing chain replaced, however I fitted a new battery and it started first time... there was lots of screaching from the top end, so I poured some oil over the camshaft, restarted and the engine now runs sweet as a nut!...

unfortunately there is no oil circulation to the top end of the engine (camshaft) and I am running out of ideas to fix... so far I have checked the oil pump, oil-pump drive, hoses to and from filter/oil cooler, oil cooler, filter head, replaced oil filter, replaced oil filter head gasket, checked oil delivery tube (over camshaft), etc., etc., and have come up with nothing... ...oil is flowing around the engine, but its not getting to the top-end which says to me either poor oil pressure or a blockage; unfortunately the oil pressure guage is not working so I cant check the pressure at the moment

I am about to start stripping the top end of the engine, as I am wondering if there is a blockage in or around the cam bearing housing where the oil feeds upto the oil delivery tube over the cam-shaft...

If anyone has any ideas, can point me in the direction of someone who can help, or some techincal documents/workshop manuals (I am reluctant to spend $150 on MB workshop manuals) I would be grateful

thanks in advance
b

[cth350]

The manuals are more than worth it. Though you can get them used on ebay pretty cheaply. There is a book specific to the M115 engine that has among other things, a diagram for the oil galleries. The other book for your car is the chassis manual.

Just thinking out loud, if you start pouring a 50/50 mixture of kerosene and tranny fluid down from the camshaft feed point, it should come out at the oil filter. If it doesn't you found your blockage.

I've never seem a dead oil pressure guage. check the fittings and plumbing lines for blockage.

a little late to say it, but always lube the cams liberally when starting a dormant engine. It's easy to do and severly cuts down on the wear. Once the engine starts turning (not running), check the piss tube for proper function.

-CTH

Thanks for the info... the gauge is probably OK, but I think the gauge line from the filter head has seen better days!.. as for starting with no oil in the top end, the plan was just to see if a big (1100cca) battery would turn it to check if it was siezed or not, but it turned over about 3 times and fired up to a steady tickover straight away!...

the main problem Ive had is deciding where the oil goes to/from; so far I have got it down to...

pump in the sump, up shaft to bottom of distributor, across to the cam-shaft bearing housing at front of engine, into oil-supply tube over cam-shaft, down through galleries into filter head, oil cooler, filter, back to sump.

If I run the engine with the hoses off the oil cooler (I wondered at first if the oil cooler was totally blocked) I get glugging oil from one of the hoses, so I am assuming the oil is being pumped around the system but the pressure/flow is v.low at the oil cooler because its on a return path to the sump (its probably only pumping about 1 or maybe 2 litres per minuite at tick-over).

Im not sure how much oil should be pumped at 1000-1500rpm, so if this is v.low compared with a good engine could the pump need replacing? I have done a visual check on it, and it looks fine, and doesnt appear to be stiff or damaged, so I assumed the pump itself was fine

sorry for all the questions, adn thanks again for the help so far

b

[psfred]

Make sure the oil tubes between the cam towers are intact and that the rear one is installed right way round -- the oil supply is up the rear tower to the oiler tube, thence to each cam bearing and there are usually holes for oil to drip on the cam lobes.

I know for a fact on the M117 V8 the left and right rear towers will interchange, but if installed "swapped", there will be NO oil to the cams, and they won't last more than a couple miles.

My first guess is that someone pulled the "locator" sleeve on the rear tower off with the bad tower when the oil ran out and a new cam was installed, and put the new on in wrong, or that the oiler tube is either leaking badly or missing.

Typically, the oil on a Benz will go straight from pump to oil filter housing, through the main oil filter and from there to the main oil gallery (#2 main) either directly or via the oil cooler as determined by the thermostat in the oil filter housing. Oil pump is operated by the dizzy shaft and the dizzy keys to the top of the drive gear, but it IS possible that the pump shaft is broken or the oil pump is bad. You can, I believe, pull the gear and replace it with one minus drive teeth and use a 1/2" drive drill to spin the oil pump in situ. We do this to pre-oil engines, but it will also work to veriy the pump operation.

I believe you can replace the oil pump through the lower pan opening, no need to pull the engine.

Get a mechanical gauge to check the oil pump before investigating anthing else, as you will shortly ruin the engine if the pump is bad.

Peter

thanks for the information... I am starting to think the issue has arrisen during the timing chain change, so its possible something is wrong or missing in the towers I guess.

I will check voer these things and report back, but its gonna be next week because its raining and Im going to the states on saturday morning for a week

b