[Esixty1]

So my engine's poked because the crank bolt came loose and therefore timing got seriously out of whack...well the cams probably stopped turning while the pistons continued on their merry way smashing into any valves that may have got in the way...

A replacement used engine is one option, but they're few and far between in my country, cost plenty, and usually of questionable service history, while the swap would also cost a fat stack in labour and I'd have to tow it to somewhere reputable to do the job, which is a long way from my town...

So I figure I may as well open this one up, assess the damage and look at getting the head rebuilt, if that's all it needs. I'm assuming I should be able to remove the head with the engine in the car...? I've already removed the cams (the ledges are showing wear from the hook ring seals, so will need replacing for a start) and performed a leak down test, which really only shows number 6 as not leaking significantly.

Looks like the tricky bit will be moving the exhaust/turbo manifolds out of the way enough. What do I need to do here? Is there enough flex in the setup to simply get away with removing the 16 flange nuts for those manifolds, or do I need to unbolt a lot of other stuff tied into the turbos in order to get sufficient clearance to remove the head?

Any help on this front appreciated guys, thanks!

[Esixty1]

Originally Posted by Esixty1

Looks like the tricky bit will be moving the exhaust/turbo manifolds out of the way enough. What do I need to do here? Is there enough flex in the setup to simply get away with removing the 16 flange nuts for those manifolds, or do I need to unbolt a lot of other stuff tied into the turbos in order to get sufficient clearance to remove the head?

Guys, any pointers here?

Thanks

[homemade_f81]

Can't give you any real pointers here - just my personal experience. I've done it on a couple of cars and I had the engine out in both cases - just found it much easier to work on than trying to contort myself into the tight spaces. I would suspect that you can get it done with the engine still in the car since the turbos can be removed without pulling the motor. To me, the pain of working around it warranted engine removal.

[Fundguy1]

Engine out i believe. I replaced mine because it was cheaper. Where are you located?

[Boland01]

It can be done with the engine in but a lot easier with it out. You may have other damage too such as bent connecting rods etc,.. I would pull the motor and see just what you have to deal with. If you end up needing a new motor you'll have to anyways. Good luck.

[d21spike]

Same situation here ... this might help you and if you have any questions feel free to ask.

http://iocoder.com/n54rebuild/

[klipse]

Originally Posted by d21spike

Same situation here ... this might help you and if you have any questions feel free to ask.

http://iocoder.com/n54rebuild/

nice

[d21spike]

Originally Posted by klipse

nice

Thanks

[Esixty1]

Originally Posted by d21spike

Same situation here ... this might help you and if you have any questions feel free to ask.

http://iocoder.com/n54rebuild/

Wow, that's awesome, we really are in the same boat!

I've got as far as removing the cam ledges, intake manifold, oil filter housing etc. I've removed the 16 nuts for the exhaust manifold/turbos (3 of the studs came out in the process) but there's no movement there...do I need to loosen anything else off to get sufficient clearance to remove the head, or will it all come apart once the head starts to come free? I'm not looking to remove and service the turbos at this stage, if I can avoid it. Mine's right hand drive too, as if it wasn't tight enough down there already. I can tell it's probably a fine line between doing it in the car or pulling the motor.

You were obviously happy with the pistons and bores? I think my crank bolt ultimately came completely loose and valves it the pistons when cranking it in the drive - that's when it made a nasty noise and the cranking tone changed (probably less compression all of a sudden) so maybe my damage is not so severe. The rockers were where they were supposed to be and the cams look fine. I'm on slightly less miles than you. I wonder if this crank bolt my prove to be
a common problem on higher mileage engines...servicing isn't going to help with this issue unfortunately.

[d21spike]

Originally Posted by Esixty1

Wow, that's awesome, we really are in the same boat!

I've got as far as removing the cam ledges, intake manifold, oil filter housing etc. I've removed the 16 nuts for the exhaust manifold/turbos (3 of the studs came out in the process) but there's no movement there...do I need to loosen anything else off to get sufficient clearance to remove the head, or will it all come apart once the head starts to come free? I'm not looking to remove and service the turbos at this stage, if I can avoid it. Mine's right hand drive too, as if it wasn't tight enough down there already. I can tell it's probably a fine line between doing it in the car or pulling the motor.

You were obviously happy with the pistons and bores? I think my crank bolt ultimately came completely loose and valves it the pistons when cranking it in the drive - that's when it made a nasty noise and the cranking tone changed (probably less compression all of a sudden) so maybe my damage is not so severe. The rockers were where they were supposed to be and the cams look fine. I'm on slightly less miles than you. I wonder if this crank bolt my prove to be
a common problem on higher mileage engines...servicing isn't going to help with this issue unfortunately.

Ok this is going to be from memory so if I forget something forgive me.

1.) Remove cowl/cabin filter
2.) Remove passenger side strut brace (I managed to get away with just unbolting it from the strut tower.
3.) Remove engine cover
4.) Remove coil packs
5.) Remove injector lines (manual states to mark them, but I don't see why)
6.) Remove fuel rail
7.) Remove airbox or DCI
8.) Remove chargepipe
9.) Remove throttle body
10.) Struggle with evil black box eventually removing it
11.) Remove intake manifold
12.) Remove fuel feed
13.) Disconnect coolant lines from head/oil housing
14.) Disconnect oil cooler lines if present
15.) Remove oil filter housing
16.) Remove engine fan (chargepipe clips into it, simply pull away)
17.) Remove vacuum canisters
18.) Remove coolant reservoir
19.) Remove boost solenoids and bracket
20.) Remove v-bands from downpipes to turbo
21.) Remove nuts holding on the turbos to head
22.) Remove serpentine belt
23.) Unbolt rear inlet (held by 2 bolts, 2 on inlet the bracket can stay on the head)
24.) The chargepipe from turbos to intercooler may hinder turbo movement, I removed mine since the turbo's were coming off anyways
25.) Remove valve cover
26.) Use timing tool to lock cams in place
27.) Remove timing tensioner
28.) Remove vanos
29.) Since your crank bolt is already out you should be able to pull out the hub with the harmonic balancer attached
30.) Remove hex plugs (I think 3) to gain access to and unbolt the timing guide
31.) Remove timing guide with chain
32.) Remove camshafts with bearing ledges
33.) Unbolt and remove head

I think your biggest issue is the downpipes being attached to the turbos and/or the chargepipe attached to the turbos. They will still be in place pretty well but will have enough give to separate from the head prior to it's removal. On the topic of not removing turbos, being higher mileage you will want inspect your wastegates (I almost guarantee that the bushings will have play.) Also the turbo drains can become clogged it proper oil changes haven't been kept up with. So as much as you want to avoid it, it still might be in your best interest while everything is apart. Keep in mind that it wont take much force to lift the head, so if you're really prying then you probably left something attached.

On the topic of pistons and cylinder bored. Usually with cylinder walls there are a few things to look for.

1.) Evident scratches
2.) Glazing
3.) Crosshatch

Only one of those three is something you want. If you see scratches then you need a hone job. Glazing isn't as bad but not great either. Seeing crosshatch throughout is an indicator the walls are in good shape (without measuring of course). As far as the pistons, overall they looked good no cracks or anything (pretty much why I cleaned the hell out of them). Then all the pistons settled at the same deck height (relatively speaking). This tells me no bent rods. I still want to measure to be sure. With some oil or lubricant I am able to spin the crank and it rotates without catching or binding.

On the topic of you reusing your head. Here in the US the valves were roughly $50 each new, then you want to refresh your valve seals around $100, and lastly I could not find a source for valve guides. So if yours are damaged, which they probably are, then you will be out of luck. Another head is your better option.

With the crank bolt, it's happened to others and with less mileage. I plan on machining a lock washer for it as well as lock-tite. It's unfortunate that it happens and having the timing cover part of the block makes the damage exponentially worse, but I don't think it's related to mileage. If anything I think it's harmonics that loosen it. The torque on the bolt is pretty high, so that's the only thing that makes sense to me.

Originally Posted by d21spike

Ok this is going to be from memory so if I forget something forgive me.

[335e92tx]

yep, thanks for the effort.

[d21spike]

Haha no problem, it's frustrating when something like this happens and even more frustrating when the job gives you grief. Just gotta take it one step at a time and examine everything. The biggest thing to consider is do what you can while you're in there because you don't want to do this again. Overall I'm about 2.7k into parts and machining, could have had another engine for less.

[Esixty1]

Thanks for all the info above. I did most of what you've listed out above, with the exception of loosening the v-bands for turbos to down pipes...have done that now but still no movement. Probably once the head bolts are gone, everything will free up? I see I'm going to need one or two larger torx bits than I presently have.

Originally Posted by d21spike

Overall I'm about 2.7k into parts and machining, could have had another engine for less.

That bit scares me and, like you, I can get another used engine for similar money. I didn't expect valves to be quite as costly and I certainly haven't anticipated replacing 20 of them...the moment of truth will be in the coming days hopefully.

[d21spike]

Originally Posted by Esixty1

Thanks for all the info above. I did most of what you've listed out above, with the exception of loosening the v-bands for turbos to down pipes...have done that now but still no movement. Probably once the head bolts are gone, everything will free up? I see I'm going to need one or two larger torx bits than I presently have.



That bit scares me and, like you, I can get another used engine for similar money. I didn't expect valves to be quite as costly and I certainly haven't anticipated replacing 20 of them...the moment of truth will be in the coming days hopefully.

My suggestion would be to see what else is binding and make sure the downpipes are off of the turbos. The way the manifold flanges are on the turbos, they actually are recessed into the head with the gaskets filling the gap. Wouldn't want you to start lifting the head and then fight the alignment dowels as well as the turbos.

That was my point pretty much, once you assess your damage you can get a better picture of what you need to do. If you think about it 20 valves at $50 is 1k. I had over 1k in gaskets, timing components, and other miscellaneous things. If I were to do this all again, I probably would have purchased another motor and refresh the common leak points as well as maintenance items. This would have gotten me on the road much quicker and I would be able to either rebuild my motor at my leisure or part it out recouping much of the cost.

[Esixty1]

Well, aren't I feeling like a right twat.

So the head is off and if I fill the intake and exhaust tracts with water, they are all water tight, with the one possible exception being an exhaust valve on number 3, which very slowly will form a bead of water. There is no sign on the valves or pistons of contact having been made.

Obviously I'll be sending the head off to the machine shop, but does this potentially mean that I don't have any bent valves? I was of the understanding that these were interference engines and thought that merely turning the cams and crank out of unison, to bring the timing back into line, would have caused damage, if it hadn't already been done - I guess in hindsight I could have backed off the cam ledges/shafts, got everything lined up and wound the ledges back down again. Are these engines perhaps only interference at high revs? I was WOT if 2nd or 3rd when it went into limp mode, so I don't know. A compression test was performed, which made for ugly reading, and the leak down test I did was ugly too, but I wasn't very thorough in checking on where the air was escaping, or if the gear was even working correctly and properly sealed (had to modify the fittings to get them into those tight spark towers).

Aside from carbon buildup in the combustion chamber surfaces, it looks good upon first inspection, with the crosshatch honing marks still clearly visible on the bores.

Thanks again to d21spike for the valuable tidbits of info!

[d21spike]

Originally Posted by Esixty1

Well, aren't I feeling like a right twat.

So the head is off and if I fill the intake and exhaust tracts with water, they are all water tight, with the one possible exception being an exhaust valve on number 3, which very slowly will form a bead of water. There is no sign on the valves or pistons of contact having been made.

Obviously I'll be sending the head off to the machine shop, but does this potentially mean that I don't have any bent valves? I was of the understanding that these were interference engines and thought that merely turning the cams and crank out of unison, to bring the timing back into line, would have caused damage, if it hadn't already been done - I guess in hindsight I could have backed off the cam ledges/shafts, got everything lined up and wound the ledges back down again. Are these engines perhaps only interference at high revs? I was WOT if 2nd or 3rd when it went into limp mode, so I don't know. A compression test was performed, which made for ugly reading, and the leak down test I did was ugly too, but I wasn't very thorough in checking on where the air was escaping, or if the gear was even working correctly and properly sealed (had to modify the fittings to get them into those tight spark towers).

Aside from carbon buildup in the combustion chamber surfaces, it looks good upon first inspection, with the crosshatch honing marks still clearly visible on the bores.

Thanks again to d21spike for the valuable tidbits of info!

Glad to hear it wasn't as bad as mine nor as bad as you expected. Quick and dirty way to see valve contact would be to look at the valves. In the picture I included you can notice the shiny line on the valves surface from piston contact. In regards to the valve integrity I'd say just let the experts handle it. They can pressure test the head for you and find out if there are any leaks. Best case there aren't any, worst case you need to replace a few valves, in a general case might need a valve lapping. All things considered this would be a good time to get valve seals done.

On the topic of the bottom end, crosshatch is visible that's great. Do you best to verify piston heights, if one is lower than the rest you might have a bent rod (unrelated to this issue).

Either way good luck, I just picked up my replacement head from the machine shop and now I gotta finish cleaning it. Guess telling them I wanted it to be drop in ready wasn't enough.

Originally Posted by d21spike

In regards to the valve integrity I'd say just let the experts handle it.

Originally Posted by d21spike

I just picked up my replacement head from the machine shop and now I gotta finish cleaning it. Guess telling them I wanted it to be drop in ready wasn't enough.

That's the problem to begin with; assuming that every machine shop employs experts

[d21spike]

Originally Posted by FCobra94

That's the problem to begin with; assuming that every machine shop employs experts

Very true, unfortunately for me there's only like 2 places that do this type of work in my area and only one had a hot tank. So my options were limited. Previously they did work on an Acura head for me and it came out looking brand new, this on the other hand I would have left the head there if I didn't need to put this together. Oh well, at least I'm capable to finish it off.

[Esixty1]

Originally Posted by d21spike

and lastly I could not find a source for valve guides

^ This bit might be a bit of a problem for me.

The head is at the machine shop and he has a few of the exhaust valves out and, while they are looking straight on initial inspection, the guides are a bit on the worn side and he's certainly advising replacing them. But like you, I'm having trouble finding any. BMW NZ don't seem to be able to track them down, so maybe they only sell them with a complete head. I'll keep hunting, but if anyone knows of a source, please let me know.

How's yours coming along, Spike?

[d21spike]

Originally Posted by Esixty1

^ This bit might be a bit of a problem for me.

The head is at the machine shop and he has a few of the exhaust valves out and, while they are looking straight on initial inspection, the guides are a bit on the worn side and he's certainly advising replacing them. But like you, I'm having trouble finding any. BMW NZ don't seem to be able to track them down, so maybe they only sell them with a complete head. I'll keep hunting, but if anyone knows of a source, please let me know.

How's yours coming along, Spike?

If I recall correctly MMP makes his own (custom) and possible others are as well. So that may be the only route. As far as mine, got a little slowed down with the holiday and some personal issues. The replacement head is my possession again, just gotta finish my cleaning, pull the front main seal, and begin reassembly. Hopefully more progress this week.

EDIT: Forgot to mention, make sure you check/clean your non-return valves (BMW PN: 11367541692) in the head. I stumbled across a thread about them and decided to check the ones in my replacement head and sure am glad I did.

[specialist]

can you just clean it and put it back? where do those even go?