engine and drivetrain Oil pump reassembly confusion

[murphykevin15]

I can't find anything specific enough for what I'm doing anywhere on the forum but as I'm rebuilding my engine I found that the oil pump piston that goes in the pressure relief portion of the oil pump is giving me trouble. IS IT POSSIBLE THAT ALL MODELS MAY NOT NEED THE OIL PUMP PISTON? I was looking into the oil pump pressure relief setup and it doesn't look like it does anything because there seems to be a manufactured blockage between the oil spout and the tube that connects from the top of the engine to it. Am I missing something here? The Chilton's Manual shows the oil pump piston pointing two different directions, which way should it go?

[Buckeye]

don't what year car or engine you have. Here are a couple links to study, assuming you have got an M10 engine. see section 11 (Engine & Mechanical)

 

And also exploded view of oil pump

http://bmwmobiletradition-online.com/bmw/partgrp.do?model=2215&mospid=47140&hg=11&fg=30

[TobyB]

No, you need the piston.  Without it, you'll have no oil pressure.  All models, 1966- 1986.

 

And the piston should go so that its top, with the cutaway reliefs, is facing oil pressure.  Away from the spring.

Which comes back down from the main galley in that little sheetmetal tube that bolts to the front of the block.  #10

 

So while the pressure regulator is part of the pump, it regulates (bypasses excess) from the front end of the main galley.  They're not hydraulically connected inside.

 

Pay attention to the o- ring that fits between the pump and the sheetmetal tube- I've had several come out on me.  #7, lower

 

t

 

www.realoem.com drawing:

 

 

 

 

[KFunk]

Be veeeery careful here.  Search the forum thoroughly, as many, many guys have screwed this up.  The usual issue is someone jams the piston up inside, and on first startup there's essentially no excess pressure relief, and oil rockets out of the oil filter.  The other semi-common issues are misinstallation of the o-ring toby mentioned, as well as not properly putting the washer and loc-tite on the sprocket. 

[murphykevin15]

On 10/1/2016 at 10:47 AM, TobyB said:

No, you need the piston.  Without it, you'll have no oil pressure.  All models, 1966- 1986.

 

And the piston should go so that its top, with the cutaway reliefs, is facing oil pressure.  Away from the spring.

Which comes back down from the main galley in that little sheetmetal tube that bolts to the front of the block.  #10

 

So while the pressure regulator is part of the pump, it regulates (bypasses excess) from the front end of the main galley.  They're not hydraulically connected inside.

 

Pay attention to the o- ring that fits between the pump and the sheetmetal tube- I've had several come out on me.  #7, lower

 

t

 

www.realoem.com drawing:

 

 

 

 

One problem I'm having when I assemble it the way you are describing is once I place the oil piston facing upwards towards the engine block, there is so much pressure on the spring to get it screwed down and it doesn't thread all the way down. It seems like the way you're describing puts too much pressure on the piston itself?

[jimk]

Let's review the valve installation.

1. With the valve piston, pc 26 removed there should be a clear hole thru the pump body.  The hole is almost the same size all the way thru.

2. install the piston as was stated with it's close end (with bevels on two sides) into the bottom of the pump hole so the piston faces up towards the engine.

3. Install the spring.  If it is the correct spring, it's end will only stick out of the pump body less than one wire diameter of the spring. (Almost flush with the pump body.

4 Thread in pc 24.  The one I have has the nozzle extending from it towards the engine pan.  On the pump I am looking at, Pc 24 almost threads all the way into the pump body before it begins to compress the spring.

 

Where in the above steps do you begin to have differences?

[murphykevin15]

Jim, for me the piston does not go all the way down the hole, instead, there is a casted ring on the inside of the hole itself that stops the piston from going all the way down, leaving the piston protruding out of the hole about 1/8th of an inch. This means that once I put the spring into the back end of the piston, I have to use pc 24 to compress the spring in order to get to the threading on the oil pump itself. I ordered the piston from BMW Parts of Atlanta using the same diagram from above and the spring is original so I might have the wrong one? Either way something is not right because of the notch inside the pump hole that is stopping my piston. Thanks for the help!

[KFunk]

Note that there have been a couple different styles of oil pumps used over the years.  Older ones have three bolts holding the sprocket to the pump, while newer ones have just one nut.  Older ones have a rigid tube connected to the relief valve, while newer ones have the loose fitting tube.  Some people use E21 pumps and mix and match pick-ups, too.  

I bet you want to make sure you have the right spring and piston for the pump you have.

Edited October 3, 2016 by KFunk

[Buckeye]

23 minutes ago, KFunk said:

Note that there have been a couple different styles of oil pumps used over the years.  Older ones have three bolts holding the sprocket to the pump, while newer ones have just one nut.  Older ones have a rigid tube connected to the relief valve, while newer ones have the loose fitting tube.  Some people use E21 pumps and mix and match pick-ups, too.  

I bet you want to make sure you have the right spring and piston for the pump you have.

According to realoem diagrams part numbers for following components are the same regardless of sprockets holding configuration.

Piston   11421271320

Compression spring        11411744324

OIL PUMP HOUSING      11411267199  with sprocket 3 hex bolts holding

OIL PUMP HOUSING      11411267199 with sprocket one hex bolt holding

 

As KFunk mentioned it is not impossible there is mix and match by PO

 

[jimk]

I disassembled a 2nd pump and is the same as the first one that I took apart.  The piston in both goes all the way to the top of the pump to the cast in ring where the rubber o-ring rests on.  The piston measures 12mm OD.

[Guest_anonymous]

the relief valve piston slides through the bore, if it doesn't, the bore might be chamfered. Might want to look for a new oil pump or have the bore sleeved to a new piston. either case the pump housing is suspect, do you want to trust the rest of your engine to this?