Oil pressure slow to appear on startup

[Mike Goble]

I put a 91 M30B35 in my Bavaria recently and the oil pressure is very slow to catch on a cold start. I used the original oil pump and added the pickup and pan that fit the E3. Once the pressure has been established it works very well, 70# while cruising down the road at 3000 rpm.

I changed oil this morning and found that the filter canister was nearly empty, as opposed to being mostly full with the previous M30B35. Is there a check valve in there somewhere that I missed?

 

[Dowst]

In my experience with M30's, it's not entirely unusual for the light to take up to 5 seconds to go out on a cold start. However, your description of an empty filter housing is abnormal. I can't remember ever encountering a filter housing (BMW or otherwise) that did not have a check valve intended to keep a "prime". The B35 is no different.

I believe this image is of a B35 housing. That little ball valve at 6 o'clock is the check valve. Sounds like yours is stuck open or otherwise defective. I would check it out right away.

 

[HB Chris]

Did you keep the b30 oil housing?

 

[Mike Goble]

Did you keep the b30 oil housing?

I kept the housing that came with my B30, but it's a top bolt setup.
I noticed that there is no check valve in the housing. I have a similar top-bolt housing with a check valve in it. Tomorrow I will swap them out and post some pics.
The oil pump in my 'new' B35 motor runs a lot smoother as the old one would vibrate the gauge constantly. Perhaps the old pump has the check valve in the pump.

 

[sfdon]

Please tell us you installed the 10mm fine threaded bolt in the block if you are using the earlier canister.
Pretty serious issue.

You have my phone #?

 

[Mike Goble]

Please tell us you installed the 10mm fine threaded bolt in the block if you are using the earlier canister.
Pretty serious issue.

You have my phone #?

Oh yes I did. I actually used a 1/8 pipe plug and it screwed right in. Oil pressure is great - 75# or so running down the road.

 

[Mike Goble]

The old one is on the left. Note that there is no check valve, only a bypass valve.

looking directly at the check valve:

None here:

They have the same casting number:

 

[HB Chris]

79 and 85? date stamps?

 

[Mike Goble]

79 and 85? date stamps?

It appears that way. 79 - no check valve, 85 - check valve. It works well now, oil pressure comes right up.

 

[TedS]

Same problem... only I read this thread first and thought I got the right filter canister. It takes 10 seconds for the oil light to go off and opening the filter canister there's very little oil in it. Of course I had to first figure out that the oil light bulb was burned out.
I'll get another one and compare it.