New to me M3, sparkly oil, looking for impressions

[cobra]

Definitely some weird stuff going on there. My cams show MINOR scuffs on a couple of the lobes, but it hasn't changed in 50k miles so I never much worried. Yours looks a bit worse and the metallic sludge certainly isn't good.

[Pklauser]

So here's something interesting. Looking at the intake-side chain guide:



Does anyone see anything suspicious?

That guide should have a layer of plastic over it like this, no?

[cobra]

Yes. Looks like you're takin it apart!

[Pklauser]

🤔 That could explain the non-magnetic particles: the guide metal, and the magnetic particles: the chain 🤷♀️

How the heck does this even happen? Used cars... Also, not seeing much in the way of guidance for tackling this, but I suppose I've gotta remove all the belts off the front, and pull the timing cover.

[cobra]

That one is not well documented because it never wears out. I'm also confused how they managed to mess it up.

Likely have to remove the vanos unit to slacken the chain enough to fish it out of there. Someone else can surely chime in with more info.

[heinzboehmer]

The plastic part on my chain guide broke. I've got pics of the replacement process in my journal.

But, I'm pretty sure the breaking was not due to the guide wearing out. What I think happened is that the bolt that goes through the head backed out and someone replaced it with a longer one. The longer bolt was what I think broke the plastic on the guide.

Also, to remove the timing cover you have to at least loosen the oil pan. If you plan on checking the bearings anyway, might as well do it then. Technically, you're supposed to remove the head too, but I got away without doing that. You're supposed to remove it to replace the head gasket, otherwise you risk getting oil leaks from there. Probably wouldn't recommend not removing the head, but also mine has been fine, soooo...

[jet_dogg]

How much did you pay for this thing?

Seems you're still shooting in the dark man, take it to a pro and rest easy it's not worth all this headache.

[Pklauser]

The plastic part on my chain guide broke. I've got pics of the replacement process in my journal.

But, I'm pretty sure the breaking was not due to the guide wearing out. What I think happened is that the bolt that goes through the head backed out and someone replaced it with a longer one. The longer bolt was what I think broke the plastic on the guide.

Also, to remove the timing cover you have to at least loosen the oil pan. If you plan on checking the bearings anyway, might as well do it then. Technically, you're supposed to remove the head too, but I got away without doing that. You're supposed to remove it to replace the head gasket, otherwise you risk getting oil leaks from there. Probably wouldn't recommend not removing the head, but also mine has been fine, soooo...

Thanks for the info, I'll definitely take a look through your journal. I read similar things elsewhere about how you're technically supposed to remove the head, but I'll roll the dice for now. Good thoughts on the oil pan, I agree that makes the most sense and will probably be my next move. The PO seems to have been honest about the valve adjustment and allegedly checked the rod bearings as well, so maybe he's not deceptive, he's just not observant? About the metal in the oil or the missing plastic on the guide that is... Either way checking on the bottom-end bearings myself will give me the peace of mind.

Let the fun begin!

[sapote]

Pulled the valve cover today. Cam lobes don't look too hot, still not clear what would cause the wear I'm seeing on them. Here's the worst one:

Cam lobe picture looks quite bad. You should replace the cams and followers, as good used stock cams are not expensive on ebay. The lobes should be shiny smooth. If rough like this it will eat the follower.

[Pklauser]

Cam lobe picture looks quite bad. You should replace the cams and followers, as good used stock cams are not expensive on ebay. The lobes should be shiny smooth. If rough like this it will eat the follower.

It's not a bad idea, especially since I'll have the vanos off to do the chain guide stuff. Used stock cams aren't expensive, maybe ~$200, but those followers! I'm seeing $67 per follower, so that's $1600! Yeesh, that's as much as a used head with cams. At that point it almost seems like I should be upgrading cams if I'm spending that kind of dough on new followers.

Is there some secret source for followers I'm not aware of? Seems unwise to reuse the old ones on good condition cams.

[Pklauser]

Got the timing cover off today, yep there's the plastic part of the guide...



It looks like the top plastic stay just broke and allowed the whole thing to slide down. Not a failure I've seen mentioned before, but also doesn't seem like a result of incorrect installation or anything.

heinzboehmer, looking at your journal, there was enough depth to get the lower bolt threaded back on? I know yours was sheared, so removal was probably pretty easy lol. I can't get a wrench in there with any room to turn, going to grab some crows feet and see if they'll enable me to get in there. Hoping that I can then snake the guide out without having to pull off the vanos sprockets or anything.

I also spent some time looking at the oil cooler once I removed it from the car. Flushing clean oil through it shows that it's holding onto a fair amount of metal particles. I'm guessing it wasn't replaced when this engine was, so that's on the list. Sounds like there really isn't a good way to clean metal out of these coolers and they should just be replaced. I'd hate to buy a new one @ $500 and fill it with any metal that remains in the motor, so I may scrounge eBay for one, confirm there's no metal coming out of it when I get it, and run that for a bit. The oil I just drained from the pan was only in there for my oil pressure test and there was noticeably less metal in the oil that came out of the pan vs the oil that came out of the cooler, so it's definitely suspect.

[heinzboehmer]

heinzboehmer, looking at your journal, there was enough depth to get the lower bolt threaded back on? I know yours was sheared, so removal was probably pretty easy lol. I can't get a wrench in there with any room to turn, going to grab some crows feet and see if they'll enable me to get in there. Hoping that I can then snake the guide out without having to pull off the vanos sprockets or anything.

I think I had the VANOS off when I changed mine. I do remember putting the lower bolt in and then installing the guide, but it was really tight. I'm not sure if you'd be able to get it in/out with the VANOS still on.

[sapote]

Got the timing cover off today, yep there's the plastic part of the guide...



It looks like the top plastic stay just broke and allowed the whole thing to slide down.

On a new guide, what hold the plastic and aluminum part together? rivet or glue?

going to grab some crows feet and see if they'll enable me to get in there. Hoping that I can then snake the guide out without having to pull off the vanos sprockets or anything..

Setting the vanos timing is fairly easy and I did it without the official bridge tool. It's a good time to Loctite the cam bolts to avoid damaging the engine if they came loose.
If you don't have the bridge tool: you can estaplish a base line by measure the current vanos timing and later use this to restore the timing as stock:
1. measure the current timing: turn crank to TDC compression stroke. Remove the vanos piston caps, then with a 24mm wrench turn cam until the piston end about 1mm protrudes out of front hole. Do for 2 cams. This is to ensure both cams are at max retard. Now, install the caps back on the vanos, and the caps will push the pistons (and the cams) back to the precise retard position. The cam timing hole should be almost 90 to the head top surface. Select a rod or drill bit which fit perfect inside the cam hole, and use a carpenter 90* angle and line its side on both the cams, and its vertical side should be almost inline with the drill bit now, but not quite. Use a caliper to measure the gap between the drill bit and the carpenter edge at the top of the drill bit (record the drill bit top position and use it later). So the carpenter + drill bit + caliper will give you the same result as the bridge tool.

2. timing the vanos. If you don't know then ask the questions.

[Pklauser]

I think I had the VANOS off when I changed mine. I do remember putting the lower bolt in and then installing the guide, but it was really tight. I'm not sure if you'd be able to get it in/out with the VANOS still on.

I wasn't very clear in my description. VANOS being on or not should only affect chain tension, but the real limiting factor I see is the depth of the mounting pin vs the window in the head to slide the guide forward and back along the axis of the crankshaft. This picture illustrates what I'm talking about better:



Note that even if I pulled the VANOS off (very top left of the photo), that wouldn't buy me any room to pull the guide towards the front of the engine and over that lower pin/bolt.

As I'm typing this I'm realizing what you might've done, with the chain out of the way, did you swing the guide as far to the passenger's side as you could to clear the head? Almost seems like the passenger's lower guide would have to come out to do that, which honestly I should just replace both while I'm here.


sapote, thanks for that explanation! To be honest, I'll probably just buy the pin tool if I end up needing to pull the VANOS off. The bolts have already allegedly been loctite'd and I can see that the Beisan Systems pump disc has been installed, so I'm inclined to trust it. I'm not vehemently against pulling the VANOS right now, just trying to manage scope.

As far as what holds the plastic and metal together, it looks to me that the plastic just has some molded T pieces that hook into the ends of the metal part. See my picture earlier in the thread from ECS and you can see the plastic T I'm talking about. It seems that T gave way on mine. For what it's worth the rest of the plastic was very stiff and I snapped it while testing its flexibility out of the car, surely the heat has gotten to these parts.

[heinzboehmer]

As I'm typing this I'm realizing what you might've done, with the chain out of the way, did you swing the guide as far to the passenger's side as you could to clear the head? Almost seems like the passenger's lower guide would have to come out to do that, which honestly I should just replace both while I'm here.

Yup, I wasn't very clear with my answer either . Reason why I said I had the vanos off is because I also took off the timing chain sprockets. I'm pretty sure I did exactly what you said. Don't remember removing the passenger's side guide though.