M30B35 oil pressure feed for turbo: where to tap?

[iamcreepingdeath]

Hi, I have searched and found no definitive or clear answer. I need to know where exactly in the oil filter housing do I tap for oil pressure to the turbo. This is for the M30B35 specifically. There seems to be three chambers in the base of the oil filter housing. Which one of those is pressurized by the oil pump? I have so far found conflicting and unclear information from my searching.

Found this pic on the internet. The left side is the B35 oil filter housing. Which chamber do I tap? The main big one?

[Shawn D.]

You tap where you'll get filtered oil, which is the cavity where the center of the filter feeds to (filter oil flow goes outside > inside), which is the big one.

[iamcreepingdeath]

You tap where you'll get filtered oil, which is the cavity where the center of the filter feeds to (filter oil flow goes outside > inside), which is the big one.

That makes sense, thanks for confirming that for me!

[tschultz]

Here's a pic i found online which helps support what Shawn D. said.

[iamcreepingdeath]

Here's a pic i found online which helps support what Shawn D. said.

I found that as well. Unfortunately that is for the B34 engine, not the upright style B35 oil filter housing.

[iamcreepingdeath]

You tap where you'll get filtered oil, which is the cavity where the center of the filter feeds to (filter oil flow goes outside > inside), which is the big one.

More questions: so the pressurized oil from the pump must first go into the the oil filter housing via the bottom oval hole (in the above pic), which appears to go through a spring loaded valve, then the oil fills the filter housing, is forced through the filter from the outside in, then then flows back down the center pipe inside the filter, and back into the engine via the large opening.

What about the funny shaped opening on the right? I read somewhere that that drains back into the oil pan, but only while changing the oil, so does the oil pressure hold some kind of check valve shut preventing that from happening while the engine is running?

[iamcreepingdeath]

Can I actually run the turbo oil return back into the other side of the oil filter housing where it drains into the block?

I am also trying to avoid having to remove my oil pan to install an oil return.

[tschultz]

Can I actually run the turbo oil return back into the other side of the oil filter housing where it drains into the block?

I am also trying to avoid having to remove my oil pan to install an oil return.

Sam, only if you have a pump or the turbo is high enough to allow gravity feed return. If the line has to go up at all, oil will not drain properly and it will have excess pressure into the turbo and may leak past the turbo shaft seals.

[iamcreepingdeath]

Can I actually run the turbo oil return back into the other side of the oil filter housing where it drains into the block?

I am also trying to avoid having to remove my oil pan to install an oil return.

Sam, only if you have a pump or the turbo is high enough to allow gravity feed return. If the line has to go up at all, oil will not drain properly and it will have excess pressure into the turbo and may leak past the turbo shaft seals.

Sure, makes sense, but what if I plumb the oil drain back into the other side of the oil filter housing, where it drains back into the oil pan?

Specifically the left side chamber in this pic:
(green left side is return, red right side is filtered pressurized feed)


Note that in the B35 (at least the one I have) there is no plug installed, and I read that that drains into the pan. Is that true? If so, can't I just plumb the turbo oil return into that chamber of the oil filter housing?

[iamcreepingdeath]

To somewhat answer my own question, I have a spare M30B35 engine on an engine stand, and I poured ATF (auto trans fluid, because that's what I have tons of) into the oil return chamber (shown in above pic w green arrow) and sure enough, it immediately poured out of the oil pan drain, so that verifies that it does indeed drain into the oil pan, so in that case, I will plan for my turbo oil return to go into that chamber.

Does anyone foresee any issue with this?

[tschultz]

If the line has to run over the engine, it could be problematic as I mentioned since the turbo will be on the other side. Also consider the size -8 or -10AN size drain line you would have to connect.

[iamcreepingdeath]

If the line has to run over the engine, it could be problematic as I mentioned since the turbo will be on the other side. Also consider the size -8 or -10AN size drain line you would have to connect.

Yeah that may be a challenge. I'll take a look at possible routing if it is possible to loop around the front of the engine (probably not), so I may just have to drop the oil pan and weld in a bung after all...

[euroshark90]

I would suggest not plumbing the drain back to the oil filter housing drain. It won't have enough flow to keep the oil from backing up into your turbo.
Try drilling into the block just above the oil pan. There is a flat spot on the exhaust side of the block that fits a 10an fitting perfectly. Size the drain to a 10an hose, and 4an oil feed.

[iamcreepingdeath]

I would suggest not plumbing the drain back to the oil filter housing drain. It won't have enough flow to keep the oil from backing up into your turbo.
Try drilling into the block just above the oil pan. There is a flat spot on the exhaust side of the block that fits a 10an fitting perfectly. Size the drain to a 10an hose, and 4an oil feed.

Thanks! I ended up doing exactly this, although my aluminum TIG skills are still developing, and it doesn't look pretty, but should do the job.

Also, before I start the car, I will verify I am getting oil flow by draining the turbo drain into a bucket and "starting" the engine w the fuel pump off, and verify that oil is flowing. Granted, I expect oil flow to be much slower while cranking as opposed to the engine running, as cranking rpm is very low compared to idle rpm.