You can't put a screen because the lever has to roll on the IP timer sprocket.

Sixto
87 300D

What about a screen with an opening just big enough for the lever?

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Bushing (No roller Bearings???) on the Injection "Timer" Shaft wear.
(It's actually more closely related to a Governor that controls/advances Timing
of the I.P.)
Timer shaft "wobbles" Radially and it's only a matter of time before the V.P.
self destructs.

I suspect many of the OM 6XX.XXX engine V.P. failures are the result of this.

You used to be able to buy parts for the Timers...No Longer in U.S.

So, you're looking at Three failure possibilities:
1.Bearing failure on the V.P. roller
2.Bushing failure on the Timer Shaft.
3.Worn "Ramps" on the Timer that actually "Push" the V.P. 's roller as they
rotate.(With "Ramp" wear ,just replacing the V.P. only ruins a new V.P.)

F'ing Pierburg swears there's no DESIGN defect with the system...
There may not have been on the older V.P. s used on the older ('75 -84')
engines, BUT the Quality of Even Brand New Pumps from Mercedes is for
Excrement.
A vital component that has the imminent capability to "Catastrophe" an engine SHOULD HAVE NO PARTS MADE OF "POT METAL" !!!!!!

Most of All you need to scare yourself awake @ night is here:
OM603: Vacuum pump explosion, bearing intact! Injection Pump Timing device wrecked

__________________
'84 300SD sold
124.128

Sounds like an electric vacuum pump is the safest route.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Possibly but a big advantage of Diesels is they keep going after the battery and alternator give up. With an electric pump they'll really keep going

Sixto
87 300D

Just have to have strong legs.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

BUT,I swear this would make me rest easier 75K from now:
http://www.diyelectriccar.com/forums/showthread.php/mes-dea-gast-vacuum-pump-which-37410.html

__________________
'84 300SD sold
124.128

I have a spare vacuum pump from a RV that looks just like the Gast. I'll check and see what the p/n on mine is. It works as either a vacuum or pressure pump and is continuous duty. It does not draw that much current as I recall. It isn't that loud either. An added benefit is you always have compressed air to fill your tires and other uses.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

If you're really concerned, just replace it with a new one after about 200k miles. The vacuum pump is just one of many components that can fail and damage your engine, no need to re-engineer it.

We all should be concerned. Not eveyone is like you, who would not think twice about spending thousands upon thousands to replace parts in a 25 year old car. Re-engineering is good!

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

It's actually a waste of time and effort. The chances of avoiding a specific failure are very slim; something else will just fail instead. Maybe you should also upgrade your oil pump drive chain, or your timing chain, or your oil cooler hoses, or worry about a broken camshaft or harmonic balancer coming loose, etc.

Overall, my cars only cost me about $0.30 per mile over the long term. Don't obsess about one component, just drive the car and keep up with basic maintenance. This is a solution in search of a problem.

The balls are in the roller that contacts the cam. The balls would be outside the screen.

Sixto
87 300D

When mine blew up, it was parts of the broken leaver from inside the pump that ended up in the timing chain.

If there was a screen there, would it have kept the broken lever bits from falling into the timing chain?

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Who knows, maybe the screen would have ended up in the timing chain instead. If it really worries you, buy a new pump every 100k miles.