Which Diesel OIL pump fits M104 for higher flow rate?
 

The car is a 1995 AMG C36 with the M104 engine. It seems I need to change my oil pump, but I would rather use a more flowing one than the std M104 C280 one used in the AMG engine.
As I recall there is a diesel oil pump that fits the M104 perfectly but has a higher capacity flow rate/ pressure.

Can any plz advise out of which engine that pump is, and even more so the part number on this pump so I can have it ordered. Thank you for the help.

Interested as well, especially for one that has the mid sump W140 type oil pan.


Though my 93 300SE motor did have an oil pump with a 603 part number.

I'm doing this right now on my M104 because my oil pump decided to blow up.
http://i773.photobucket.com/albums/y...k/DSC00720.jpg

The diesel oil pump and the M104 oil pumps are exactly the same. The only difference between the two are the sprocket's that drive the oil pump via the oil pump chain. Mercedes doesn't sell the stock oil pump sprocket anymore, so now, the only sprocket you can buy for the M103, M104 and OM603 are the diesel 603 part # sprockets.

So, just buy the stock oil pump and sprocket and you'll have your diesel oil pump no matter what. The pumps already pump about 35psi of oil pressure at 2k rpm, what more do you need? All it takes is 3psi of pressure to get the oil from the bottom up top, the rest is volume which is plenty enough already.

Jay has been known to rev the pee out of his engine from time to time. :eek::P:cool:;):D
Regards, Eric

i dunno if oil pumps can come to lose pumping pressure and since the W202 doesnt have a pressure sensor i cant really say if my car runs low pressure or not, but here is what i get after a long flat out run.
What ever type of oil except for the castrol edge sport 10W60 if i do a flt out run for a few min back to back like in my vids running up the mountain highway. After such runs i get serious lifter knocking, i have even fitted an oil temp guage just to make sure am not cooking the oil, and it turns out am not and the hottest i have seen is abt 100c'

when the oil is very new its harder to get the lifters to knock that is i can run flat out for longer, btw even on the coldest of days i have the same issue. So im thinking maybe its a weak oil pump that cant seem to hold its own with hot thin oil.!

the pumps are chain driven, so if there's any loss in oil pressure, chances are the internal gears on the pump may be wearing or worn away.

this is how the pump looks on the inside:
http://i773.photobucket.com/albums/y...k/DSC00722.jpg

It's all gears that are pushing the oil. I suppose a thinner oil would slide past the gears without much flow, but so much to the point that you get a lifter knock I can't imagine. It MAY be a possibility that the gears on the oil pump have worn away to let that oil slip by. Either that, or you have oil flow issues somewhere on the head. Having a higher volume/pressure oil pump isn't going to do much on these engines anyway as the oil passages are tiny.

I don't know how a brand new pump is supposed to look inside, because I haven't gotten the one I ordered yet. I'll post comparison shots when I get the new pump to see how much wear the pumps go through with 160k miles on them.

I used to get similar noises when autocrossing my '97 C36AMG, but I assumed it had something to do with the oil sloshing around in the pan and uncovering the pickup. I've never had the pan out of this car, so I can't say for certain that this was the problem. I simply stopped autocrossing it.

Best Regards,
Rob

yeah, it seems sn issue on this engine, i really dunno y it might do that, while the 3.2 M104 has none of this. any way, once i start hearing the lifters knock all i have to do is slow down for a few min and the sound is gone.

Ironic is last time i heard the sound, i had reached my destination so i parked the car and turned it off, come back some 45 min later start the car and the darn lifters are still knocking the same, drove off and in a couple of miles the sounf was gone.

Does anyone know the valve spring tension of the AMG head vs the lowly plebian M104's? If it's a bit higher valve spring tension, then the motor would be more likely to push oil out of the lifters at high rpm and cause them to collapse, making that ticking sound. It is very possible that after so many miles the check valve clearances in the lifters start to go causing the oil to drain out at high rpm's. Remember the M104's priority oiling goes: Crank/rods, sqirters (they're on the main galley with the crank and rods), cam, and finally lifters. When you turn the motor off you no longer have any oil pressure to pump up the lifters, so them ticking when you start makes sense.

I wonder if there is cavitation in the pump? I know this is a problem in some high performance engines and as such most of them run the gerotor pump as opposed to the spur-gear type ala our M104 or stock BBC/SBC/ etc. FWIW the M102 runs a crank driven gerotor pump and I don't hear of them having issues with the 16v cars.

For those of you who have pushed your motors and have the pump off. Do you see very small pitting (it would look like casting flaws almost) on the tips of the rotors? That would be tell-tale signs of bad cavitation.

Bob, thanks and i think your theory of stiffer springs and worn check valves in the lifters can be spot on.