Part Number Help! Intake cam bearing cap E5 (broken)

[bmwman91]

Oof yeah if the nut is floating around somewhere and ends up between the timing chain and a sprocket it would probably be the end of the valvetrain. Gotta find that thing!

[jsnppp]

Ugh! Can't seem to find that nut! Magnet, light with video, flexible grippers all in the front timing chain area and no love. I dropped the lower oil pan and nothing there either.

It simply has to be there. I really really really don't want to pull the front timing cover off. It's basically doing this whole thing twice.

[jsnppp]

Looking at my old photo it's possible if I remove the crank pulley and possibly the front crank seal there will be enough room to fish around for the nut if it's there.

I also ordered a different flexible extended magnet that may be able to pick it up from the top. It feels like it has to have fallen in the void in the front timing cover.

[jsnppp]

FOUND THE NUT!

Ha! I bought a new magnet on a flexible wand for $12 on Amazon. It's a great tool, narrow, strong and flexible.

It only indirectly enabled me to find the nut however.

After probing for 45 min I was resigned to doing the next step, remove crank pulley and seal and fish around there.

But first I used the new cool magnet to pull up any metal in all the little pockets on top of the head and under the cam trays.

No, the nut wasn't in one of the little pockets. :-)

One of the very first things I noticed when I pulled the valve cover off was that one of the oil supply holes (assumed supply and not return) was smaller than the rest and had threads on it.

It was the nut "hiding in plain sight", just had flipped and was resting in the upper left corner oil hole on the head. The magnet moved it...

WHEW. So now I can just clean everything a million times and reassemble. More soon.

[jsnppp]

Here is a photo showing the nut before I knew thats what it was. You tell me if it's not hard to see (find waldo is kids play comparatively).

I don't lift the VC often on an M42 and so prob to some of you it would have been obvious...

[jsnppp]

Question: Should I put med Blue Loctite on the cam cap nuts? I don't believe I did when I originally rebuilt it. I'm thinking Loctite 243.

Jason

[bmwman91]

Haha wow! I am glad that you found it. Sort of like searching all over for your sunglasses when they are already up on your forehead! I'd say that it turned out close to best-case...the nut didn't end up doing damage elsewhere.

As far as the cam bearing caps and thread locker, the Chilton manual I have does not say anything about using it. But, some medium strength stuff probably does not hurt either. I can understand the desire to not have a repeat of this scenario!

[jsnppp]

Haha wow! I am glad that you found it. Sort of like searching all over for your sunglasses when they are already up on your forehead! I'd say that it turned out close to best-case...the nut didn't end up doing damage elsewhere.

As far as the cam bearing caps and thread locker, the Chilton manual I have does not say anything about using it. But, some medium strength stuff probably does not hurt either. I can understand the desire to not have a repeat of this scenario!

Totally! Found it right before serious dismantling. I was really hopeful that it was like this and can't believe I brain farted over it from the beginning. I literally saw it the first time I pulled the VC.

Won't take long to reassemble.

[jsnppp]

Well thats odd!

Put it all back together, carefully. Started it up and guess what?

Cylinder 4 is still not firing! When I pull the plug wire it does not change the engine.

The car has brand new plug wires, new plugs. New fuel injectors. I swapped in a DME that I don't know for sure works but exhibits the same behavior.

I pulled the VC off and the cam isn't broken again. Thank goodness.

I swapped coil packs too, no change. Still cylinder 4.

So then I checked compression - 190 on cyl 4 and 188 on cyl 3. This was a quick check and a medium warm motor.

I noticed that the vent hose on the VC likes to blow off. Hmmm.

At a loss here. Really thought it was just the cam. So, to my mind it could still be DME (anyone have a photo of what potentially burns up?) or a bent/broken valve?

Jason.

[jsnppp]

So, just went for a walk and thought about it all.

This feels electrical to me. Spark related, not fuel injector related.

• When I pulled plug 4 it was wet w/ fuel. Plug 3 was dry.
• I swapped coils (4 over to 3 and vice versa) and it followed the cylinder

One thing that occurred to me is that maybe it is the wire that goes between the coil and the DME. I pinned it out briefly earlier but now it feels more like it.

The only thing that stops me is that how odd would it be to have the camshaft break AND the wire to flake out at the same time?

I need to lookup again how to pin these out.

[jsnppp]

This link from bmwman91 is likely helpful for pinouts.

https://www.bimmerforums.com/forum/showthread.php?939668-91-e30-318is-M42-Crank-No-Start

Jason

[jsnppp]

I'll do the basic pinout tomorrow between black wire and the DME to ensure continuity.

However, since I am receiving spark, can't see how it's bad!

[jsnppp]

Bummer. Just pinned out the wiring and it appears to be ok.

So. It may be my DME. I have a working DME on another car but I hate pulling parts for troubleshooting.

Anyone have other ideas? Why isn't it firing in cyl 4?

Jason

[jsnppp]

So, I've tested:

• Plugs
• Plug wires
• Coils
• DME to coil wiring
• Swapped DMEs
• Changed fuel injectors

I have not tested the fuel injector to DME pinout (ugh, have to pull the intake again). Nor have I swapped in a known working DME. I only tried the one I bought from ebay.

I guess this could be a valve isse? I'd think if it was bent valve (rom camshaft break) I'd know it. And the design of the head doesn't seem to have let that happen.

I put a camera down the sparkplug hole and didn't see shards.

All thoughts welcome.

[jsnppp]

So I tested each coil and they are all within spec (0.4 - 0.8 ohm). I changed the plugs back to the original NGKRs (I'm desparate) and maybe it helped. The newer NGKs I had in there seemed to have a weaker spark.

The car runs/starts but it just feels too lumpy at idle to me. Not smooth. Not horrible but not what it was.

Here is an older video of the same engine. It feels smoother "back then".

https://youtube.com/shorts/lLK1KKTGVoM?feature=share

Something still feels wrong. I guess it could be engine timing? I can check that again too. Could it be a cam or crank sensor?

~Jason