1100GS engine won't rotate after cylinder head install

pax maac

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95 1100GS

I followed Steptoe's writeup on the cylinder head gasket change, and everything seemed fined. Taking it off was easy, rotated to TDC, removed the head.

Putting it back everything seemed fine, I took extra care to make sure that the cam sprocket tab lined up with the index slot. I got it all back together and torqued up and was ready to adjust the valves. I rotated the engine after installing the head to make sure it moved freely, and it did. All the way around to TDC again, which meant that since it was at TDC to remove the left side, I had then switched it so that it was at TDC for the right side. I adjusted the valves there and everything seemed fine.

So now I had to rotate again to adjust the left side. Well the engine went as far as being able to see the letter Z in the little window and then it will not move any more.

I thought I better check the cam sprocket, so I pulled the left head again and double checked my work. It all seemed correct. The tab was in the slot. I reinstalled the head and the engine rotated freely all the way around to the OT in the window again and then it won't go any more.

I got frustrated and walked away. This morning, I just went and checked and what I have is this-

The right side valves are wiggly, as if ready to be adjusted. But instead of the left side valves not being wiggly, the left side intake valves are wiggly as well, but not the outflow.

Any ideas on how to remedy this situation?
 
Just some first thoughts:

Presumably you think the valves are out of synch and touching the piston? Have you got something like a chopstick in through the plug hole to double check where the piston(s) is at the point it stops?

Spark plugs are out? Not sure how much resistance you're feeling to make you think it won't want to turn any further?

Are you 100% sure the chain hasn't been able to get itself into a different tooth on the sprocket? (How did you secure the chain to the sprocket, with a cable tie?

Is there any way the cam shaft could have rotated before you reassembled?

I'm sure others on here will have some ideas. Should be a straight forward job so understand your frustration.




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Yeah, cable tied the sprocket to the chain, spark plugs are out. No chopstick.

As to the resistance, it definitely reaches a point where it will not go any further. It feels wrong. You know how it feels when it's right, and then it just won't go anymore, and I tried pulling harder, hard enough that I said "this isn't right" and it won't go.
 
strip it and re do it again check for damage don't force anything always double check and make sure timing is correct please let me know how you get on
 
Unless you can think of something daft that was missed during assembly i think sheene might have suggested the best answer.

+1 for keeping us posted. You may still get something useful from here though



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Only thing I can think of is that you have adjusted the valves in both sides now the same.
One side should be with no clearance and the other side with 0.15 mm and 0.3 mm clearances when it's TDC.

Pekka
 
Sounds like you've got simultaneous compression both sides maybe. I did this:) It even ran but sounded weird, then it just shattered the end of the starter as it couldn't turn the engine! What a TWAT:) Gave it a minutes thought then worked out what I'd done! Take the plugs out - I presume you haven't? See if you can turn it then. Then you'll know
 
9 I rotated the engine after installing the head to make sure it moved freely, and it did. All the way around to TDC again, which meant that since it was at TDC to remove the left side, I had then switched it so that it was at TDC for the right side. I adjusted the valves there and everything seemed fine.

Are you definitely sure it was TDC on the compression stroke, and not the exhaust stoke on both sides.
 
Sounds like you've got simultaneous compression both sides maybe. I did this:) It even ran but sounded weird, then it just shattered the end of the starter as it couldn't turn the engine! What a TWAT:) Gave it a minutes thought then worked out what I'd done! Take the plugs out - I presume you haven't? See if you can turn it then. Then you'll know

The first thing I did was pull both plugs, since this whole episode started as just a 48k service. Plugs were the first thing I did. The plugs have been out the whole time.

Are you definitely sure it was TDC on the compression stroke, and not the exhaust stoke on both sides.

I am admittedly an amateur, an enthusiast. Better at taking things apart than putting them together, but I can follow instructions pretty well. So forgive me for not knowing how to answer this without sounding like a 3 year old- I've done valve adjustments before, and just followed the instructions that said "rotate the engine until you can see the OT in the window and check to see which cylinder has the valves that wiggle. Then adjust those, rotate the engine again to OT and adjust the other cylinder".

So when I had to pull the cylinder head (which I had done before, some 3 years ago, also using the Steptoe tutorial and everything went fine then) I had both cylinder head covers removed, I rotated to the OT and the left side valves wiggled. So I pulled the head off. The pictures looked the same, everything looked right. I didn't touch or move anything, and when it was time, I reinstalled the head. Torqued everything up, and checked to make sure that the engine would rotate freely.

I did that by turning it a little. So it was no longer at OT. And I was going to do a valve adjust anyway, so I just kept rotating it until it came back to OT, and checked which side had the valves that wiggled, so I could adjust them.

I double checked- OT in the window and the left valves were tight, right wiggled. So I adjusted the right side. Then went to rotate it once again so I could do the left side. But when it got to the Z in the window, it wouldn't go any farther.

Here's where maybe I fucked up? After getting good and mad, I thought that maybe something with the cam sprocket was off. So I pulled the left head again, double checked everything, and it all seemed fine. Put it back on, and the engine rotated around once more, back to making the right side wiggly and then again only rotating back to the Z and then getting stuck.

Now as it stands, I can't see anything in the window and the right is wiggly, and the left side the intake part is wiggly but the exhaust part is tight.

Where do I go from here? I can't see how pulling the head will help anything, plus it's not at TDC and I can't even get it there, at least not by rotating it clockwise.
 
Back all the tappets right off and start again
How much adjustment did you make it the first place? Anything more than a very small part turn would have been too much.



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OK, I may have got this wrong, I too am an amature, so feel free to extract the urine. But:

I did that by turning it a little. So it was no longer at OT. And I was going to do a valve adjust anyway, so I just kept rotating it until it came back to OT, and checked which side had the valves that wiggled, so I could adjust them.

I'm assuming that the 'OT' mark indicates the piston at TDC. But it has two TDCs, one on compression and one on exhaust. Going off what you say here, you've only rotated it once 'until it came back to OT'.

If you'd had it at OT on the compression stroke, it would now be there on the exhaust stroke. You need to rotate it
twice
to get back to OT on compression.

Myself I don't go off 'wiggly' valves, I watch them to see when the inlets have just closed as it reaches OT/TDC. I know it's on the compression stroke then.

Just my 2p worth, as I say, feel free to take the pee... :D


I had this problem once when I replaced the Cam chain on a GS850 (the Suzuki. not the Beemer). Just like yours, it would turn so far and then just stop. Took it apart again and re-assembled. No problem second time. No idea what the problem had been...
 
If i remember your op, you said you only had the head off one side? If that's right, it should be fairly straightforward to reassemble the side you did take off, just by calculating the position of the untouched side. You did say you cable tied the chain and sprocket together so that should eliminate mis-sync there.

Start from the beginning and work through it all again... i can't think of what else you can do

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If i remember your op, you said you only had the head off one side? If that's right, it should be fairly straightforward to reassemble the side you did take off, just by calculating the position of the untouched side. You did say you cable tied the chain and sprocket together so that should eliminate mis-sync there.

Start from the beginning and work through it all again... i can't think of what else you can do

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Maybe it's because I just woke up, but I'm not really understanding anybody's posts this morning. Are you all suggesting that I just pull the left head off and reinstall it again? Without doing anything? What about the fact that it's not at TDC? Does that matter?

How do I get the timing correct?

There really should be a BMW wrenching book for dummies, because I'd buy it in a heartbeat. Thanks for your patience and help so far.
 
Are you sure the timing chain sprocket is located correctly in the keyway on the shaft?

I had exactly the same symptoms as you after I took both heads off and I had not quite lined the key on the shaft with the cutout in the sprocket. This allowed the sprocket to turn individually to the engine.

If I was you I'd go back to the beginning in stages. Back off the tappets to where they were before and try turning the engine. If it still does not turn then timing is out. Then re cable tie the chain onto the sprocket and check that. If the sprocket is located correctly then using the tappets on the other side you will be able to work out where the engine is.

Hope this helps.

Tom

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I don't know if it's possible that the chain slipped on the crank sprocket if you turned the engine whilst the head was off.

If that isn't a possibility look here at Steptoe's post for changing a cylinder head gasket, it covers exactly the same scenario that you have.
 
and easy way to check the valve timing on the RH cylinder camshaft notch is downwards (i.e. 6 o'clock position) @ TDC on the compression stroke i.e. inlet valves on that side have just closed and the piston has come up to the top of its stroke

IMG_20140107_181401.jpg


Note the tensioner is NOT installed in this one and thats why it is a tiny bit off to the right


I am nearly sure that its @ 12 o'clock on the left side but I'd need to check
 


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