I've put the new oil pump in. It wasn't that difficult, but it did take a couple of days. You have to lift the engine a few inches to get the pan out, but I did not have to drain any coolant or transmission fluid. I only disconnected the upper radiator hose, turbo intake hose, motor mounts, engine shocks, exhaust hanger at the trans, and rear transmission mount. I also removed the fan and cowling. Everything else had enough movement.

The new oil pump gave me better pressure, but not what I was hoping. It is however within spec and I will live with it.

Cold start up => almost 3 bar
Cold idle => 2.5 bar
Cold @1500 rpm => 3 bar

Hot idle => 1.8 bar
Hot @2000 rpm => 3 bar

The FSM spec is "at running temperature"
Idle > 0.3 bar
3000 rpm = 3bar

I'll recheck these numbers and change them if necessary.

The cold numbers are meaningless unless there is a catastrophic problem.

The hot idle of 1.8 is a good number. The engine will never have an issue with that.

I like to note the point (rpm's) where the gauge just makes 3.0. On both of these, it's between 1500 and 1600 rpm. It serves as a good point of comparison to other engines.

I think the 2000 rpm is a minimum observed and maybe optimistic. It may be more like 2500. When I drive it around some I'll know better.

I've noticed that there are certain points where the pressure fluctuates. If I raise the rpm slowly, there is a point where the pressure drops slightly (about .2 bar) and then rises.

What really caught my attention was the FSM. I thought minimum was .7 bar, but my 603 engine manual says 0.3 at hot.

It's surprising how little oil they need when there is no load.

Has anyone actually seen OP that low at hot idle? My 603 is usually around 1.5-1.75 at its lowest even in the hot summers.

Wow, Im really impressed with the detailed photos with this build! Did you by chance have any MB manuals in PDF format for this build? If so, I would really like a copy!

Also, those seats are AWESOME! What seats will drop right into a 300SDL from other MB models? My seats are palamino like yours...but I would really like to do what you did!

Look for the ones from an 89+ S class. They do look nice :)

-J

are they gonna be direct drop ins? matching up with the plugs and floor holes?

Yes, they came from a 91 560sel. They were also a direct drop in. Except for the rears thhough. The rears mounted differently.

I had a paper copy of the manual.

Thats plenty of oil pressure, what matters is when it comes up. The pistons as you know are oil cooled and when the turbo starts spooling they need 3bar by 3k or your going to have problems.

A lot of heavy equipment will idle close to zero on hot days without issue, you don't really need any pressure at hot idle. As long as its around or over 1 bar I wouldn't give it a second thought.

nice work

this makes me so glad I got a sdl thats been dealershiped service its life. A drivetrain thats been properly serviced its whole life gives me confidence in it.

Great Thread! Thanks for posting :D

Thanks for the kind words.

This thread is fascinating and I've learned a lot reading it.

Could your oil pressure concerns in any way be caused from your expanding the bearing oil ports?

Thanks!