M20B28 no oil in head

[michael_rpt]

Hi guys. I have another problem with my damn car.. I started to lose oil pressure, I changed the oil pump and everything seemed to be fine because I gained around 5 bar on cold engine. The problem started when the temperature increased, on slow rpm pressure is 0.
I checked it with manometer. Can it be caused by drilling this additional hole? Or something else? I found something about oil pressure relief valve- maybe after 40 years it doesn't work properly anymore?

[ForcedFirebird]

I have two 885 heads, both SETA- dual springs and camshaft without bearing on 4th journal (middle one)
(:

The eta cam is missing three journals completely...
https://www.fcpeuro.com/products/bmw...ft-11311287606

EDIT: The seta cam has grooves on the other journals to pass oil, not just the center one.

[michael_rpt]

I have yet to see (in person) one of those 885 heads with a 4 bearing cam, I've done a bunch of seta swaps too, they all had a cam with smaller lobes than b25, and 7 bearings. This is the second time since 2007 I saw one come across these forums, though.

I have two 885 heads, both SETA- dual springs and camshaft without bearing on 4th journal (middle one)
(:

[ForcedFirebird]

I have yet to see (in person) one of those 885 heads with a 4 bearing cam, I've done a bunch of seta swaps too, they all had a cam with smaller lobes than b25, and 7 bearings. This is the second time since 2007 I saw one come across these forums, though.

[TobyB]

Edit- doh, didn't see page 2. Glad that fixed the problem.

...and yes, you need to drill the other four journals so that all the cam bearings get oil...


t

[michael_rpt]

Problem solved.
Holes have been drilled in heads workshop- it's not the best job I've seen but it works (:
Thank you guys for help and beware of SETA heads.
Does any schrick or catcams make cams for SETA head?

[michael_rpt]

The oil comes up the block through the hole on the exhaust side of the block adjacent to head bolt holes



There is a recess in the head so the oil crosses over into the cylinder head bolt hole (between 3 and 4) exhaust side.



There is an angle drilled hole (red arrow and dashed line) on the exhaust side that intersects the head bolt hole (oil passage) other blue dashed line. This head bolt hole is counterbored so it is larger diameter than the other head bolt holes.



The exhaust rocker shaft has the largest hole to line up with the above angled drilled hole that fills the shaft with oil



The exhaust rockers are fed oil via the smallest holes



The medium sized holes marked below are not used on the exhaust rocker shaft and are blocked off by the shaft journals in the head which have no holes.



There is also another hole intersecting on the same oil hole shown earlier. This allows oil to the camshaft middle journal with the full groove to receive oil



The oil groove in the camshaft then feeds the other (inlet) rocker shaft through the drilled hole



Oil in the inlet rocker shaft is fed to the rockers via the small holes the same as on exhaust side


Oil in the inlet rocker shaft is fed to the other cam journals via the medium sized holes



Oiling for the sprayer comes from the 1st and last journals which have a partial circumferential groove the pumps oil into the sprayer bar through a hole in each of the 1st and last cam journals in the head

Wow.. This is something.. Thank you very much, now it's more clear to me. I will check step by step my head, every hole, every journal, everything.

[digger]

The oil comes up the block through the hole on the exhaust side of the block adjacent to head bolt holes



There is a recess in the head so the oil crosses over into the cylinder head bolt hole (between 3 and 4) exhaust side.



There is an angle drilled hole (red arrow and dashed line) on the exhaust side that intersects the head bolt hole (oil passage) other blue dashed line. This head bolt hole is counterbored so it is larger diameter than the other head bolt holes.



The exhaust rocker shaft has the largest hole to line up with the above angled drilled hole that fills the shaft with oil



The exhaust rockers are fed oil via the smallest holes



The medium sized holes marked below are not used on the exhaust rocker shaft and are blocked off by the shaft journals in the head which have no holes.



There is also another hole intersecting on the same oil hole shown earlier. This allows oil to the camshaft middle journal with the full groove to receive oil



The oil groove in the camshaft then feeds the other (inlet) rocker shaft through the drilled hole



Oil in the inlet rocker shaft is fed to the rockers via the small holes the same as on exhaust side


Oil in the inlet rocker shaft is fed to the other cam journals via the medium sized holes



Oiling for the sprayer comes from the 1st and last journals which have a partial circumferential groove the pumps oil into the sprayer bar through a hole in each of the 1st and last cam journals in the head

[michael_rpt]

Yes, that's what I was talking about. The pics on this one appear to be the later Febi rocker shafts, like I mentioned earlier. I had a set of shafts so bad, the rocker pad was actually on the edge of the cam lobe.

Either way, the oil holes on the bottom of the shafts are much larger diameter than the drilled holes in the head. They would have to be really bad off to completely lack oil.

Honestly I’m a little bit confused. Can you guys please mark on my pics what can be wrong?
You think the rocker shafts can be manufactured so badly that it causes no oil flow at all?

[ForcedFirebird]

maybe its my eyes, but are the rockers offset from the cam lobe somewhat more than they should? i thought they ran closer to middle of lobe normally ? i'm not at home to check things. if so perhaps the holes in the shaft are offset a few mm and no longer line up

Yes, that's what I was talking about. The pics on this one appear to be the later Febi rocker shafts, like I mentioned earlier. I had a set of shafts so bad, the rocker pad was actually on the edge of the cam lobe.

Either way, the oil holes on the bottom of the shafts are much larger diameter than the drilled holes in the head. They would have to be really bad off to completely lack oil.

[digger]

maybe its my eyes, but are the rockers offset from the cam lobe somewhat more than they should? i thought they ran closer to middle of lobe normally ? i'm not at home to check things. if so perhaps the holes in the shaft are offset a few mm and no longer line up

[ForcedFirebird]

Ok, I made a simple drawing. This is what you mean?

The hole you marked is just left over from the drilling process. If you remove the rocker shaft, that hole goes all the way down to the cam journal. An eta head (200 casting) is missing some of those holes. There are also holes on the bottom of the rocker shaft bosses.

Digger means a "dud" as in some of the later production Febi rocker shafts had questionable quality. I had to send a set back when the rocker retainer slots were a few MM's off so bad, the rocker pad was edged off the cam lobe.

Oil to the head starts at the center of the block, next to # 1 head bolt (center, exhaust side), travels up to the top of the head, and to the center of the exhaust rocker shaft. Next, it travels around that center cam journal (the one that has a 180° slot around it) to the center of the other rocker shaft. Oil then travels from the center of the shafts to the rocker holes, then at the ends of the shafts where the # 1 and # 7 cam journals are fed, the slots on the # 1 and # 7 cam journals then feed the oil spray bar. Might behoove your shop to blow some compressed air through the head and make sure there's no obstructions.

Often times at work, I will run the m20 with the valve cover off to diagnose things. Just have to plug the big breather hose, and it makes a bit of a mess. Know it's kinda late for that (and appears you hired a mechanic), but for future reference when others look for this info, it's a great way to check on things. When I was younger, we would adjust rockers on Chevy push rods while the engine was running lol. Tighten the rocker nut until you hear the chatter go away.

Just out of curiosity, the head was completely dry when running, was a little oil pooling at the bottom of the head cavity, or just not coming out of the spray bar? How did you go about diagnosing lack of oil up top?

[michael_rpt]

I got some pics from the process while the engine was beeing rebuilt. Whats dud shaft?

[digger]

here you can see the first journal (near bottom of pic just above flange) where there is a partial groove, there is also a full groove on the middle journal.

the partial groove moves oil to sprayer bar and the full groove allows oil to moves from one rocker shaft to the next

As stated above it is possible to install shaft wrong but either the clips wont like up properly or retainer wont sit correct so this should be obvious unless you don't know how the retainer is supposed to sit.

The other thing that could be wrong is a dud shaft, they aren't what they used to be from a quality perspective.

i would disassemble and check things thoroughly.

[michael_rpt]

Reread your first post. Check the front cam journal, it should have a slot in it. The oil only passes when the slot faces the oil holes. I discovered this many years ago when I was checking a used engine. Sitting on the stand, I turned the oil pump shaft with a hand still and it built up pressure, but dead-headed. I thought something was wrong until I rotated the engine a little and the oil shot out of the oil spray bar. Long shot, but we had a member a while back that bought a cam that had the hole for the cam gear in the wrong place - perhaps that feature was left out of your cam?

Ok, I made a simple drawing. This is what you mean?