M42 running VERY loud (video), low oil pressure light is on

[bmwm42]

You can replace the oil pump without removing the engine done it many times about 6 hrs tops

[Vivek]

No way $2500. I say you could do it for under $1k if you reuse your current flywheel->diff and just changing the motor with an m50.

You know anyone currently selling what I need? If I can find what I need for a reliable and bar-able swap for $1k I'd definitely do it.

This thread is taking an interesting turn. Might be for the best, too.

Vivek, I am local and if you want to try to tear into the timing case to see what might be up with the oil pump I can lend a hand sometime. I also made a crank locking tool for breaking that big ass crank damper bolt loose, and you are welcome to borrow it. Your engine might (MIGHT) still be OK since it has not run too much, and it's probably worth spending a couple more hours to see what exactly went wrong. Still, M50 for $1k is a pretty sweet sounding deal.

Steven and I may try to go ahead and do this in the coming week, so I'll probably take you up on that offer. To check the bearings, would it be okay to just pull a bearing cap and inspect it, then torque to spec? Do you think this could have worn my rings or anything in the top end?

[bmwman91]

I can't recall...did you rebuild the bottom end or anything and put assembly grease in there, or is the only lubrication going to be whatever film of oil was left from last time it ran properly?

I'm not sure if you can get away with pulling caps and reusing everything. I want to say yes, but maybe someone that has built more engines can chime in there.

I am sure that there is a bit of premature wear at least somewhere in the system. I bet it's safe to say that the rings are "fully seated" at this point.

This whole thing still has me scratching my head. I've never seen a case where the pump was this tough to prime, but it sounds like others have. I just cannot see how the oil pump crapped out if it was running properly before you bought the engine.

[bmwm42]

http://www.r3vlimited.com/board/showthread.php?t=314343

[golde30]

This is a strange scenario. My s52 sat for 10 years without an oil pan, it was bone dry before i fired it up and never had a pressure issue, but I also poured a cap of marvel mystery oil into each cylinder through spark plug hole before firing the first time. took almost 8qt before the oil level was rite. Book says capacity is 7qt.

[Vivek]

I can't recall...did you rebuild the bottom end or anything and put assembly grease in there, or is the only lubrication going to be whatever film of oil was left from last time it ran properly?

I'm not sure if you can get away with pulling caps and reusing everything. I want to say yes, but maybe someone that has built more engines can chime in there.

I am sure that there is a bit of premature wear at least somewhere in the system. I bet it's safe to say that the rings are "fully seated" at this point.

This whole thing still has me scratching my head. I've never seen a case where the pump was this tough to prime, but it sounds like others have. I just cannot see how the oil pump crapped out if it was running properly before you bought the engine.

Nope I never touched the bottom, head, or any internals :/.

http://www.r3vlimited.com/board/showthread.php?t=314343

"I had my machinist come over today and he brought an external pump (oil) which we used to back flow the engine through the filterhousing. The system with car off held a rock solid 50 PSI throughout the fill. Once finished we reconnected the oil pressure tester and got the above results. It appears that I had air in the system (good call TobyB and Phil, BTW) which was forced out by the back pressure. Car is running normally now."

What's an external pump, and how do I get/use one? This may be my issue.

[kwill22]

Aw man I thought you were saying you got it running then I realized the quotation marks. Lol but yea sounds like what I was saying about the air being in the system between the oil pump and pickup.

I don't know what kind of external pump he used but sounds interesting. I'm assuming just a regular external hydro oil pump but I don't know how he would've ran it. I don't see anyone building 50 psi by hand. Shoot him a pm

[brads2002]

Did you replace any timing covers? I have heard of m42/44 getting confused. The m44 is slightly different bigger I think and it won't allow the pump to build pressure.

[Vivek]

Nope, never touched the timing covers. Pumping oil in may be a possibility, I'll look into it and PM him. I just pulled the oil filter housing to see if anything looked off behind there (maybe I left a piece of a paper towel in or a gasket was pinched). Everything looked fine, other than the fact that the passage going from the filter to the rest of the engine is bone dry :/.

Plan of action now is to see if I can somehow pump oil in at high pressure, and then replace the pump if that either doesn't work or isn't possible. Is there anywhere I can pour oil that could help to lubricate the parts that aren't being lubed because oil isn't flowing?

[Todd Black 88]

I would definately pour oil over the cams before start up.

[bmwman91]

I would definately pour oil over the cams before start up.

+1

Also, if you have the filter housing off try pouring some 15W-50 down the oil passage to the pump to get those gears lubed and HOPEFULLY able to force some air out. Turn the engine with a wrench a few times to make sure that the oil has made it into there and coated all of the teeth on the rotors. Alternatively, if you can get a hold of that oil pump device, go that route instead.

[bmwman91]

The following animation should explain how to put oil down the pump outlet and what to look for.

[Vivek]

+1

Also, if you have the filter housing off try pouring some 15W-50 down the oil passage to the pump to get those gears lubed and HOPEFULLY able to force some air out. Turn the engine with a wrench a few times to make sure that the oil has made it into there and coated all of the teeth on the rotors. Alternatively, if you can get a hold of that oil pump device, go that route instead.

Would it be worth it to try to start it up after doing this before replacing the pump? I PM'd the guy who posted that thread about the external pump, but he hasn't been online since last month so idk how often he'd check r3v.

[bmwm42]

there are a few guys on the pnw chit chat thread the know kevin personally i used to have his number but lost it when i switched phones kid325e 2man pretty much anyone on there can get a hold of him for you

[bmwman91]

Would it be worth it to try to start it up after doing this before replacing the pump? I PM'd the guy who posted that thread about the external pump, but he hasn't been online since last month so idk how often he'd check r3v.

Tough call. The engine has run a lot without oil already, but another 3-5 seconds might be fine. Pull the valve cover and get oil on all of the moving parts and down the chain. If it did work, then you probably wouldn't need to replace the pump rotors. Still, I think that your #1 goal should be to borrow the pump thing and get some oil in there before running it.