rebuilding a 5 cylinder diesel. relacing sleeves, rings ,mains rods, head shaved, cylinder bored to match pistons. wsa looking at oil pump, cannot figure how oil is being pumped to the oil gallerys. I know how an oil pump works, but first on a mercedes engine build. There is a hole on top of the pump that seems to be a discharge port. but it is just open to the oil pan. is there a web site that any one knows where i can get a exploded view of the oil pump and related parts. I have rebuilt many a ford and chevy, but this is new to me. I dont mine asking questions or taking advice. Also should or could i rebuild this oil pump. On any new engine i have rebuilt i replced oil pump, but at 150.00 that bites the pocketbook. Help! Thanks

I would recommend reposting this in the Diesel forum.

It is probably the most active forum on this site.

I'm sure Larry Bible is one of the diesel guru's who could answer your question.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

If I remember correctly you will see the oil passage when you unbolt the oil pump from the block. There is a hole and o-ring where the oil leaves the pump and enters the oil passages on the block. I would base it's replacement on how many miles are on the engine. If 250k+ I would go ahead and replace it, otherwise I would leave it alone. You can replace these pumps without removing/lifting the engine. You just have to drop the small oil pan.

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Jim

Jim answered the oil pan question, but I want to comment on your "head shaving." Remember, this is a diesel with a CR over 20:1, not an SBC with 8:1 or 10:1. Don't mill ANY off the head unless absolutely necessary for straightness, and it probably won't be necessary, this is an iron head.

The combustion chambe is so small, that the tiniest cut will drastically raise compression which can rapidly get excessively high.

I agree that the pump is expensive, but so is this engine. I would replace it.

Final comment. I am probably the Maverick on this site when it comes to sleeving versus boring for new piston fitment. The pistons in ANY diesel engine are highly stressed. I prefer to replace them with oversize and just bore to that oversize. If you insist on reusing them INSPECT THEM CAREFULLY. I have seen ring land failure and other maladies.

If it comes to replacing pistons, there are two types. The piston type is determined by the prechamber type, so make SURE they match.

You did not mention the timing chain. Check for stretch before disassembly. If it is stretched at ALL, this is the time to replace it. Also inspect the guide rails closely.

Good luck,