How screwed am I?
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As I have never pulled the timing cover on an m/s52, do I have the potential of messing up the head gasket by pulling the cover? I am really hoping to not have to pull the head...
well anything can be f*d up, but you don't seem like the guy who would do that. the timing covers are designed to come off without the need for replacement the headgasket at the same time. i'f its anything like the m60/m62, i'd imagine the bentley manual suggests using some sort of sealant around the part of the headgasket that will be exposed when resealed.
Dan
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Idk man. Flakes from chain/sprocket wear are usually fine from what I have heard. Plus I'm sure you would have seen flakes in the filter if it were the bottom end. Not to mention more dense material would migrate to the bottom not the head. If you still have the oil you drained run a magnet through it.
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Idk man. Flakes from chain/sprocket wear are usually fine from what I have heard. Plus I'm sure you would have seen flakes in the filter if it were the bottom end. Not to mention more dense material would migrate to the bottom not the head. If you still have the oil you drained run a magnet through it.
I had gotten rid of the oil before I found the problem unfortunately, what is in the car now is fresh. If there were any metal pieces in the old oil I did not see them when pouring it from my drain pan into containers to take to the disposal place so any in there were minimal. But, to be fair I didn't really scrutinize it because I was short on time. There was nothing in all the random pockets around the head, it was all concentrated in the opening of the cam and some around the inside edge of the vanos sprocket on the exhaust cam.
Finer shavings would make sense in a normal situation, but my current theory is this: (this is what happens when a mechanical engineer is left alone with their thoughts...)
The oil pump sprocket could be loose (oil pump nuts coming off is common) and wobbling around on the shaft with the chain causing slightly bigger pieces when it gets out of alignment before the chain nudges it back straight. Here, a metal flake is born. It could be one or two flakes very rarely, maybe even a hundred miles apart, and they get carried up the main timing chain while any that are sucked up by the filter get caught there and don't get any further into the engine (I did find a few small pieces in the filter, but certainly not many or any amount that was alarming). This could've been going on for a while as the oil pump nut failures were happening as early as 50k miles and maybe even earlier (I've got just over double that), and the opening of the exhaust cam is the only place in the whole timing chain path that isn't being bathed with oil and washing any particles back down into the sump, so it could make sense that shavings could collect there. The car was never driven hard according to the previous owner who had it since 2001 and 30k miles, so its possible that the oil pump nut became loose but did not fall off thanks to the left hand threads. He changed the oil every 3k like I usually do so that may not have given it a lot of time to accumulate shavings in the pan either. Is this completely and entirely crazy and mostly for your entertainment? Yes. But after this I'm out of ideas...
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JosephStrackbein said:
Idk man. Flakes from chain/sprocket wear are usually fine from what I have heard. Plus I'm sure you would have seen flakes in the filter if it were the bottom end. Not to mention more dense material would migrate to the bottom not the head. If you still have the oil you drained run a magnet through it.
I had gotten rid of the oil before I found the problem unfortunately, what is in the car now is fresh. If there were any metal pieces in the old oil I did not see them when pouring it from my drain pan into containers to take to the disposal place so any in there were minimal. But, to be fair I didn't really scrutinize it because I was short on time. There was nothing in all the random pockets around the head, it was all concentrated in the opening of the cam and some around the inside edge of the vanos sprocket on the exhaust cam.
Finer shavings would make sense in a normal situation, but my current theory is this: (this is what happens when a mechanical engineer is left alone with their thoughts...)
The oil pump sprocket could be loose (oil pump nuts coming off is common) and wobbling around on the shaft with the chain causing slightly bigger pieces when it gets out of alignment before the chain nudges it back straight. Here, a metal flake is born. It could be one or two flakes very rarely, maybe even a hundred miles apart, and they get carried up the main timing chain while any that are sucked up by the filter get caught there and don't get any further into the engine (I did find a few small pieces in the filter, but certainly not many or any amount that was alarming). This could've been going on for a while as the oil pump nut failures were happening as early as 50k miles and maybe even earlier (I've got just over double that), and the opening of the exhaust cam is the only place in the whole timing chain path that isn't being bathed with oil and washing any particles back down into the sump, so it could make sense that shavings could collect there. The car was never driven hard according to the previous owner who had it since 2001 and 30k miles, so its possible that the oil pump nut became loose but did not fall off thanks to the left hand threads. He changed the oil every 3k like I usually do so that may not have given it a lot of time to accumulate shavings in the pan either. Is this completely and entirely crazy and mostly for your entertainment? Yes. But after this I'm out of ideas...
Haha I like your train of thought. I considered that but the cam timing chain is on the outside where the deposit is. How did it jump chains? You peaked my interest now. Did you see any wear on chain as if it were gouging into the sprocket? I have never had any experience with vanos rattling. Why did you rule that out?
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Haha I like your train of thought. I considered that but the cam timing chain is on the outside where the deposit is. How did it jump chains? You peaked my interest now. Did you see any wear on chain as if it were gouging into the sprocket? I have never had any experience with vanos rattling. Why did you rule that out?
That's the part of the theory that I can't figure out, unless there is oil pushing them in that direction. Thing is, they would have to jump from the oil pump chain to the crankshaft timing chain to the cam timing chain. Neither chain I was able to see (crankshaft and cam chains) showed any signs of damage. I ruled out the shavings being caused by the vanos because I had the entire unit apart on my bench when I did the seals and rattle repair, the bearings were in good shape and the splines on both the vanos unit and the cams were also ok, no abnormal wear anywhere.
I have to do the brakes on the car I am borrowing for the time being because they're grinding pretty bad, and then hoping to get my valve cover off again maybe tomorrow after work to start investigating further.
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I have to do the brakes on the car I am borrowing for the time being because they're grinding pretty bad, and then hoping to get my valve cover off again maybe tomorrow after work to start investigating further.
Your car has problems. You borrow a car so that you can work on your problem car. Instead of fixing your problem car you work on the car that you borrowed... It seems like you somehow turned 1 problem into 2. You're better off walking...
In all seriousness I would inspect between the two exhaust cam sprockets to make sure the slotted inner one hasn't come loose at any point. I noticed you had the torx bolts off already. Were they easy to come off?
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Your car has problems. You borrow a car so that you can work on your problem car. Instead of fixing your problem car you work on the car that you borrowed... It seems like you somehow turned 1 problem into 2. You're better off walking...
In all seriousness I would inspect between the two exhaust cam sprockets to make sure the slotted inner one hasn't come loose at any point. I noticed you had the torx bolts off already. Were they easy to come off?
It gets better than that, I have to do the rear main seal, valve cover gasket, ball joints, and potentially the pinion bearing and carrier bearings on my girlfriends xj as well. It hasn't been a good week for me haha, but to be fair I am replacing the brakes on the Jeep I am borrowing from my parents as a thank you for them letting me borrow it all the time lately.
You have to remove those torx bolts in order to remove the vanos (I had the cams locked with the proper tool and the engine locked at TDC, don't worry), they were very tight and took enough force to crack loose that I busted up my knuckle pretty good on the first one. I removed the exhaust cam sprocket completely after I found the shavings and the surface between looked ok. I think the best plan of action is to just start taking stuff apart and get a better look/tons of pictures
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Safety wire that oil pump nut! The m50 I pulled, the nut was finger loose. I safety wired the one in my s50
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Started tearing into the car this afternoon, got the valve cover back off and after quite a bit of searching around I found this clue:
It is made of black plastic but is not the same material of the tensioners so it couldn't have come from them. It is about 3/8" by 1 inch long and was sitting on top of the lower chain tensioner where it meets the guide. You can see it way down there where the inner side of the tensioner should be.
Any idea what it could be from? Maybe a cover for a sensor or something? I checked over the valve cover and all the other plastic parts in the head and nothing stood out to me as the source.
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Pulled the oil pan yesterday, oil pump nut was on there tight (took it off for safety wire/loctite) and there was nothing in the pan. Crank sprocket and oil pump sprocket in good shape. Nothing looked wrong with the crank/rods that would indicate a problem and I could still see crosshatching on the #1 and #2 cylinder bores. Stuck a magnetic pickup everywhere and didn't find any shavings. Didn't pull the windage tray as it didn't seem necessary at that point. Got a look at the timing chain guides and they are not broken or misaligned so I don't think I need to go through the trouble of pulling the timing cover.
What I did find was the other piece of that plastic cap I pulled out on Saturday, it fell out of the oil pickup tube as I was taking it off (replaced with a z3 2.8 tube). I'm pretty convinced that it was foreign so I'm glad to have found all the parts of it. I'll post some pictures of things later today. At this point I have no idea where else to look without pulling things like the cams.
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yeah, that plastic piece looks a cap which wouldnt be found anywhere inside the engine. i looked through realoem and didnt see anything that stood out in the diagrams. maybe someone just dropped it down the oil filler and when the engine was started it contacted the chains/cams on the way down it took a little chuck out somewhere and those are the shavings you see?
Dan
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yeah, that plastic piece looks a cap which wouldnt be found anywhere inside the engine. i looked through realoem and didnt see anything that stood out in the diagrams. maybe someone just dropped it down the oil filler and when the engine was started it contacted the chains/cams on the way down it took a little chuck out somewhere and those are the shavings you see?
That's what I'm thinking, the material didn't look like anything you would find in the engine either...I wonder how long it's been there. It looks like it was crunched at some point so it definitely got in the way somewhere. As it sits right now, the car had been running really well so I don't think I need to do any additional work as far as tearing it down. I am going to put the car back together and just keep an eye on things. The magnetic drain plug should be good for collecting any leftover shavings (it is from turner, the magnet is VERY strong) and now I don't have to worry that it is the oil pump or something like that in the bottom end. I will pull the valve cover in a month or two to see if any new shavings accumulated there as well.
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Got the car all put back together and back on the road. It is running great with no horrible noises or anything you would expect with an engine that has decided to become a lathe so I am pretty confident that these shavings were related to that plastic piece in some way and have accumulated over a long period of time. I found nothing in the pan and no unusual wear anywhere that I could see. I ran a magnet through nearly the entire length of the exhaust cam and this is all I could pull out. For size reference, that is a very small magnet, probably under 1/4", I cleaned everything obsessively so any new shavings I find down the road wouldn't be residual from an old problem.
I will be sending a sample of the oil at the next change for analysis (already got my sample kits from blackstone) and pulling the valve cover to reinspect everything in a few thousand miles. I almost wish I found something that was wrong but I'm glad I didn't find anything horrible. Thanks for all the help and suggestions!
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good plan. after you watch it for a while and get no new pieces, you'll be happy you found nothing. they also make magnetic gizmos you can clamp to your oil filter housing to capture metal shavings if you are inclined.
Dan
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