Squeeling Metallic Noise... No Bueno

[Rocan]

Driving over the Manhattan bridge into Manhattan when I noticed a slight loss of power. Pulled onto Canal street and noticed a metallic noise that sounded like an alternator belt at first. Popped the hood and listened as it got louder and I noticed it came from the head which was recently replaced (along with other gaskets, timing chain, guides, etc). Loudest near the distributor, but no distributor as I am running megajolt. No tapping or clanking noise, but it sounds like the Cam was running dry so I killed the motor and waited 3 hours for a tow truck. Towed it to local shop (no garage ) and will assess in the morning. I had added oil to the head while waiting to see if that did anything, and noticed the noise quieted for a second, but then came back.

My ideas are something came lose in the head, or possibly the head isn't getting oil. Oil pan and other covers were really gunky, but everything was thoroughly cleaned and the car received a new filter and oil after the rebuild... What came out was nasty (I haven't had the car all too long, so first oil change... beforehand it leaked and burned oil so quickly that it would get a quart a week). Perhaps something came lose and blocked an oilway? Anyone experience anything similar before?

I should add... motor appears to be a 1973 block, the head is one of the last E12 castings (mid 80s) and was extremely well built.

[Mike Self]

could have come loose or was reinstalled without the copper washers on each side of the hollow feed/mounting bolt...That spray bar is the primary lubrication for the cam and rockers.

Have the garage do an oil pressure test with a gauge (temporarily replacing the oil warning light sender) to make sure oil is reaching the head...a worn oil pump might get enough oil to the rods and mains to keep 'em happy, but not enough to the head.

Hope it's something simple! Let us know.

mike

[Rocan]

could have come loose or was reinstalled without the copper washers on each side of the hollow feed/mounting bolt...That spray bar is the primary lubrication for the cam and rockers.

Have the garage do an oil pressure test with a gauge (temporarily replacing the oil warning light sender) to make sure oil is reaching the head...a worn oil pump might get enough oil to the rods and mains to keep 'em happy, but not enough to the head.

Hope it's something simple! Let us know.

mike

I definitely didn't double check that when I did the install. I haven't had an oil pressure light come on in a while (it used to flicker when my oil level got low). I'll hook up a gauge and see what it reads. I wasn't aware what that bar was for, honestly didn't really think about it much. I wouldn't be surprised if it was clogged or missing the washers.

Is there a schematic of the oil feed to that bar? I'll check through the shop manual pdf and see what I find in the meantime. I did notice that the bar on the new head sat a little bit closer to the sprocket than on the old head.

[Rocan]

...I'm starting to get the feeling I forgot to install the banjo bolt for the oil sprayer.... I was a bit hasty when getting it back together (had to drive back and say bye to my grandparents before they went back to europe, and made it with not a minute to spare). I know, I know, never rush things, but I didn't want to have that on my conscious that they left without saying bye, yada yada.

I'm figuring that since I put in new oil, the head was oiled enough to be okay for the drive back and the short jaunt I had a few days ago, but finally dried out enough to show signs of issues....

ideas?

[c.d.iesel]

[Rocan]

Picked up car this morning. The mechanic had started it and heard no noise. I didn't either. I popped valve cover off and all was okay... Cam was very

Well oiled and all looked well. Drove home with no issue... All power is back. Ran motor for a while looking for something wrong, found nothing. I was thinking a possible alternator or water pump bearing/ bushing? Didn't sound like it was coming from there and without the sound no point in disconnecting drive belt. They were changed within the last 2000 miles, while the PO had it.

Maybe something in bell housing that got knocked free on the bumpy flatbed ride home? This is driving me nuts. Way way too cold to be working on it. Not to mention the snow.

[Napes]

FWIW The washer refered to in c.d.'s diagram above (#5) is no longer a crush washer. I just got a new one from BMW earlier this month using the same P/N and it is a thin, flat aluminum washer - not copper or a crush washer.

Bob Napier

[PaulTWinterton]

I'd agree with a VERY loud water pump. If left to sit, during a rebuild let's say, I've witnessed that screech, until the coolant deposits have been driven away. My theory anyway.

The sound is loud enough to come from anywhere, and your loss of power is probably in your head. YOUR OWN HEAD, cause your baby is screaming.

[Rocan]

FWIW The washer refered to in c.d.'s diagram above (#5) is no longer a crush washer. I just got a new one from BMW earlier this month using the same P/N and it is a thin, flat aluminum washer - not copper or a crush washer.

Bob Napier

My new head had the very same aluminum washers. My 73' head has the copper crush washers (and, interestingly enough, 4 of them instead of two...).

Water pump was cleaned out and hasn't made any noises before. Also it looked relatively new, as most all of the cooling items were replaced by the PO. Is there any other way to check for wear besides feeling for play in the impeller/shaft?

[Guest_anonymous]

Not to just throw something out there, but what else squeels back in the bell housing area in neutral besides a dry or burned up pilot bearing ?

Rocan, 1 oil change on a fresh engine which is a daily driver after 4-6mths ? Or did i mis-read something.

[Rocan]

Unfortunately so, first oil change since I owned it. I know it should have been one of the first things I did... no need to scrutinize me and banish me to the underworld reserved for only the worst of BMW abusers.

I was mostly holding off since I had to change the head and do all the seals anyway, and didn't want to put in fresh oil just to have to dump it all once I removed all the covers, gaskets, and head. Oil is expensive, and the quart or so a week I was losing was enough to be a noticeable expense. All bad reasons, as I know the importance of clean oil. Just a little bit hard to work on the street in Brooklyn.

...Great, now I feel like an irresponsable owner since I broke one of the main rules of maintenance...

[Rocan]

Not to just throw something out there, but what else squeels back in the bell housing area in neutral besides a dry or burned up pilot bearing ?

...Now that I think about it, pilot bearing is a possibility. Wouldn't it receive oil from the crankcase? I had always noticed a bearing noise when stopped in neutral with my foot off the clutch, but I had always figured it to be the throwout bearing since engaging the clutch (pedal down) made the sound go away.

Also the sound I am describing in the original post is far different then the sound mentioned above.

[Guest_anonymous]

Shame not intended. I'm in the midst of a complete rebuild after years of short cutting. One of which I had blown a head gasket and spun a bearing, and, had let the car sit for three years. Just a little protective of the time and cost into the upkeep at this point and would hate to see that happen on a fresh engine.

No, the pilot bearing does not get oiled from the crank case. It is in a cavity in the crank surrounded by the rear main seal. Modern bearings are sealed or (closed faced) older bearings are open faced with a felt ring and dust cap which gets oiled during installation and servicing as well as packing the bearing proper. Either can fail, and a good idea to replace while the trans is seperated from the block...(read project creep here)

Nonetheless expect oil consumption. I was told 1qt every 1000 miles IIRC, but will be corrected I'm sure.

[Rocan]

Any way to diagnose pilot bearing without dropping the trans?

[Rocan]

So the alternator, water pump, cam chain tensioner, chain, chain guides and head are all new, and the head is getting plenty of oil, which rules out those parts failing. What bearings or things near the rear of the engine make noise? It's present in neutral, and in gear with clutch in or out. I haven't heard it since the incident, so it's any bodies guess.