HELP 2001 740i died, cranks, tries to catch then dies

[ConvGeorge]

Crankshaft bolt is 27mm.

[Timm]

That couldn't have just snapped and jammed the cam - it must have been left there by the PO.....

[al535e34]

I couldn’t believe my eyes either but yes, I won the unlucky lottery. The broken bolt jammed the exhaust cam and spun the sprocket off it, so the chain didn’t snap. I guess I shouldn’t complain as that in its self is considered lucky.

The head was never touched in the engine and I owned the car for the last 4 years. I did the valve covers a couple of years ago and didn’t check them. I’m not sure what the odds of it being snapped if any work that was undocumented by PO and lasting 4 years and 13k of driving.

My plan is to retime that bank (tighten the cam sprocket), fire it back up and if all is well, take the heads off, replace both head gaskets, chains and chain guides. Also thinking of taking the heads to a machine shop and replacing all valve seals, oil separator, oil pump chain and gaskets in the way. What else should be done while I’m in there. Mind you this might take me all summer as I’m linited on time to work on it

[al535e34]

Thanks ConvGeorge. I did pick one up from Harbor Freight after my 1 inch (~26 didn't fit) and didn't find a 28mm.

[951Dreams]

I wouldn't trust just tightening it back up to fix the timing. I'm understanding now, that bolt was loose and got in the cam. Your lucky in many ways, I've seen conflicting info, but I'm pretty sure the valves and pistons share some space. If it had stuck with a valve in that space.....

Dang, what a project! If it were me, and I had the heads off, I'd do the valve job for sure, replace or at least test the springs, seals... you name it. Wouldn't be cheap on these monsters, but worth it if you love the car. Do the VANOS for sure! I'm not sure how many miles you have on it (can't look back ATM) but you MIGHT think about doing the rings if it's high. You should be able to drop the pan, and push the rods/pistons out through the top. Then you could do the rod bearings and rings. I'm not 100% sure it's doable that way on these, but if it's not I'm not aware of why. However, most of these german Alusil lined engines don't have ring issues in my experience (in Porsches). And I also haven't read about bearing issues on these. But just because I haven't read it doesn't mean it not a thing! Someone more knowledgeable on these can chime in. This is pretty common stuff to do on the 944's I'm used too, but then we have 1/2 the cylinders. So it's much cheaper, and our cars are much older. Just some ideas if you have the heads off...

EDIT:

Rewatched your video, with SOUND this time. Makes MUCH more sense. That's just crazy, that goes in the book as one of the unlucky/luckiest things I've seen.

Personally, I wouldn't try anything else till I'd pulled that head and checked everything out top and bottom. That took some force to unscrew that sprocket, I'd want that cam checked out before I spun the engine again. If those forces tweaked the cam at all then you could tear up the journals and no telling what else. That's my .02...

[al535e34]

I wouldn't trust just tightening it back up to fix the timing. I'm understanding now, that bolt was loose and got in the cam. Your lucky in many ways, I've seen conflicting info, but I'm pretty sure the valves and pistons share some space. If it had stuck with a valve in that space.....

Totally agree that I got lucky as how the cam was jammed allowed for the engine to rotate freely without the piston hitting the valves. I was able to rotate the engine easily until I remove the bolt and the CAM opened a set of valves and the engine would rotate by hand until it no longer moves as it reached the valves.

Dang, what a project! If it were me, and I had the heads off, I'd do the valve job for sure, replace or at least test the springs, seals... you name it. Wouldn't be cheap on these monsters, but worth it if you love the car. Do the VANOS for sure! I'm not sure how many miles you have on it (can't look back ATM) but you MIGHT think about doing the rings if it's high. You should be able to drop the pan, and push the rods/pistons out through the top. Then you could do the rod bearings and rings. I'm not 100% sure it's doable that way on these, but if it's not I'm not aware of why. However, most of these german Alusil lined engines don't have ring issues in my experience (in Porsches). And I also haven't read about bearing issues on these. But just because I haven't read it doesn't mean it not a thing! Someone more knowledgeable on these can chime in. This is pretty common stuff to do on the 944's I'm used too, but then we have 1/2 the cylinders. So it's much cheaper, and our cars are much older. Just some ideas if you have the heads off...

I plan on getting the valve seals done, but not sure about pulling the pistons and dealing with the rings and bearings. It has ~134K on it, so not too bad.

EDIT:

Rewatched your video, with SOUND this time. Makes MUCH more sense. That's just crazy, that goes in the book as one of the unlucky/luckiest things I've seen.

Personally, I wouldn't try anything else till I'd pulled that head and checked everything out top and bottom. That took some force to unscrew that sprocket, I'd want that cam checked out before I spun the engine again. If those forces tweaked the cam at all then you could tear up the journals and no telling what else. That's my .02...

I'm thinking get the timing in place, tighten it, rotate by hand and check the CAM clearance against the lifters for consistency. I wasn't able to find specific info on the expected clearance, but I figured if the clearances are the same, then the CAM is straight...

[al535e34]

Just wanted to report that I was able to retime her, she fired right up and moved under her own power

Now the fun will begin over the next few weeks/months where I tear her all down, extract the broken head bolt from the block, and refresh the timing chain related parts.

I did notice oil at the back of the engine, so I'm debating and will be researching pulling the tranny out and doing the rear main seal. If there's a way to check if it is not leaking, that would be great before I have to go pulling the tranny as I have no engine hoist or tranny jack.

I appreciate everyone's help, encouragement and knowledge. The wealth of E38 knowledge here is amazing!!

Happy Wrenching and Happy memorial day to everyone!

Al

[al535e34]

Hi everyone,

It's been a little over a year since I found out one of my head bolts sheared off and the car has been pretty much sitting since. I got a few hours here and there and tore it down except for pulling the head back in September and finally in April this year, I pulled the head off. I checked the head and it was straight, no warpage, no gaps using a straight edge at different parts and across the head so I proceeded with getting a new headgasket and installing it. I followed the torquing instructions, 30 NM (22.5 ft/lb) and then 2 x 80 degrees. I made a mistake by checking bolt #1 to see if it is tight and I twisted it ~30 degrees with the torque wrench after the initial torquing and found out it was loose. I figured that's where the 2x80degrees come in after, so I didn't retorque. Not sure if that was correct or not. Fast forward to yesterday, I was able to get it all back together, I ran it and it fired up which was quite a relief but I got P0011 , so I figured my timing wasn't 100% there, which I had a feeling it wasn't.

I tried replacing the CPS as I read elsewhere could have been the issue, but got same results so I figured need to retime it. I went back in and took the valve cover off and noticed some chocolate looking oil , which is not what I wanted to see. The car has been sitting for about a year, I'm sure some coolant went down some of the oil passages as I separated the head, and I haven't changed the oil yet. The only thing in the back of my mind is whether the torquing was done correctly for the head, which was per the instructions, I would say I did it right, but looking for better guidance as reading instructions is not always intuitive. Any thoughts?

Thanks,
Al

[racer2086]

Just read through this thread. Wow what a story.

I'm confused by your torquing though. You did or did not do the 2x80 degrees on that one bolt?

[al535e34]

I did torque 2x80 for all bolts following the pattern after the initial 22.5 ft/lbs, but my main concern is after I did the initial torquing, bolt #1 which was torqued was now loose prior to the 2x80. I figured that's expected but want to confirm that I didn't need to do another round of 22.5 ft/lbs torquing

[al535e34]

Good news, I retimed bank 1 of the engine tonight and put it back together, fired it up and no more P0011 As soon as it fired up I knew it was working right as there was no more hesitation and it sounded healthy

I will tidy up the bottom side tomorrow and do a road test as it hasn't been driven for about 10 months now and see how it goes. Wish me luck and thanks for the help here and all the other threads. You guys are awesome!!

[racer2086]

Great to hear. What about the chocolate oil? Is there coolant mixing with it?