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  #1  
Old 02-28-2007, 07:01 PM
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OM617.952 cylinder head: Unable to remove

I'm seeking to remove/replace the cylinder head on my 1983 300CD-T (Calif.)'s OM617.952 engine (242,000 mi.).

Problem: I have been unsuccessful thus far at pulling the head off.

So far:
*All 22 of the 12-point head bolts have been successfully removed.
*All 4 of the 6mm hex bolts (two in the timing chain gallery and two exterior of the head near the front of the engine) have been successfully removed.
*The pipe between the block and the water pump at the front of the engine has been successfully removed.
*The intake and exhaust manifolds have been successfully removed.
*The turbo charger has been successfully removed.
*The cooling system hose on the glow plug side of the engine has been successfully removed from the head.
*All of the glow plugs have had their power wires removed.
*The timing chain slide rail and pin have been successfully removed.
*The thermostat assembly has been successfully removed.
*The power steering assembly has been pulled away from the head.

When I connect the cylinder head's three lifting points to my engine hoist and apply tension, the entire block pulls updward I have held a block of wood to the manifold side of the head while striking the piece of wood with a rubber mallet to try to release the head but still no success.

Any ideas as to what might still be keeping the head so tightly held to the block? I'll admit, after removing so dogonne much from on and around the engine, this was the *last* problem I was expecting

Thanks for any advice on this one-

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  #2  
Old 02-28-2007, 07:06 PM
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get rid of that rubber mallet hit it real hard with a peice of wood and a mini sledge hit it on the exhaust mana fold side.
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  #3  
Old 02-28-2007, 08:03 PM
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Stupid question possibly, but did you remove the camshaft timing gear itself??? If not, then the timing chain is holding everything together...
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  #4  
Old 02-28-2007, 08:06 PM
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I assume you have removed the cam, cam towers and cam followers?

If all the bolts are out try using a mini sledge and a short block of wood, maybe 8" or so, and tap upwards away from the block with the wood block crook'd into one of the intake or exhaust ports.

RT
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  #5  
Old 02-28-2007, 08:07 PM
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Did you remove the three alens?, Everybody forgets those Look down where the timing chain comes through the head. Be very careful they dont fall down into the engine.
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  #6  
Old 02-28-2007, 08:43 PM
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If you are absolutly sure all retaining fasteners are out and only then. Turning engine over with the starter will lift the head. Now if you miss something you will break the head. Reffer to some literature to make positive all retainers have been pulled. Someone may have coated the head gasket with something the last time it was done. People do the unexpected sometimes.
You might also try pulling up with your hoist and then hitting the head as well to try to dislodge it. The weight of the lower block might aid you in this approach. Okay I would only try the starter bump with the chain still on. Still it would be a last resort. You might pop the head with compressed air introduced on a cylinder that you knew the piston to be at the bottom of the bore as well. Overall you might just be too gentle with your block of wood and hammer. Usually they will come that way.

Last edited by barry123400; 02-28-2007 at 09:27 PM.
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  #7  
Old 02-28-2007, 08:51 PM
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Quote:
Originally Posted by barry123400 View Post
If you are absolutly sure all retaining fasteners are out and only then. Turning engine over with the starter will lift the head. Now if you miss something you will break the head. Reffer to some literature to make positive all retainers have been pulled. Someone may have coated the head gasket with something the last time it was done. People do the unexpected sometimes.
You might also try pulling up with your hoist and then hitting the head as well to try to dislodge it. The weight of the lower block might aid you in this approach.
Yikes, what would happen to the chain if you hit the starter? I have this awful vision of the chain getting sucked down there and getting kinked or something.
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  #8  
Old 02-28-2007, 09:16 PM
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Griesel, I have refined the post. It never occured to me that someone would try rolling the engine with the starter with the chain off.
The head will only loosen. Not lift off the engine exactly. First I would try the hitting the head with the head under tension. If that failed then the compressed air making sure the cylinder used was at the bottom of its bore. A lot of times a person has missed a fastener when trying to get something apart. One has to be positive they are all acounted for before using real force.
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  #9  
Old 02-28-2007, 09:30 PM
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*The two rocker assemblies have been successfully removed.
*The camshaft sprocket has been successfully removed.
*The camshaft bearing towers plus the camshaft itself have been successfully removed.

These comments might only be differences in nomenclature...
^^I'm not sure of what is being referred to as the "camshaft timing gear" by vaman4215.
^^Ditto the "cam followers" by rwthomas1.
^^According to the FSM, Haynes, and my eyeballs (), there are only *two* 6mm allens inside the head/timing chain gallery--Stevo. Gettin' them out is cause for a tense moment or two though Of course, there are two others nearby but *outside* the head.

As far as turning the engine over right now, well, in two words, extremely unlikely. Call me gutless or wise, no matter
Interesting idea of placing a bit of tension on the hoist/chain/head combo and then tapping on the head at the manifold side.

Thanks for helping to think this through, I appreciate the extra brain power being put on this-
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  #10  
Old 02-28-2007, 09:54 PM
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I think you have gotten all the fasteners out by your description. Some heads are just stubborn.
Vaman just means the chain sprocket fastened to the front of the camshaft I think.

Last edited by barry123400; 02-28-2007 at 10:05 PM.
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  #11  
Old 02-28-2007, 11:09 PM
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I couldn't get mine to budge until I used a slide hammer like I was removing one of the prechambers. Popped it right off.

G'luck with it!
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  #12  
Old 03-02-2007, 01:13 AM
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What troubles me about all the suggestions regarding tapping with a block of wood is as follows:

The head gasket is unable to sustain the weight of the front of the vehicle and the block. Pulling upwards with the crane should easily put 1000 lb. of pull on the head gasket. I don't believe there is any possibility of the head gasket maintaining a grip with even one-half this load.

So, lift the head with the crane. If all the fasteners are out, the head MUST lift off the block. There is simply no other possibility.

You may have put 200 lb. into the cables and watched the front end come up slightly. This may not have been sufficient to break the head loose...........
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  #13  
Old 03-02-2007, 06:51 PM
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Thanks for all of the comments.

"You may have put 200 lb. into the cables and watched the front end come up slightly. This may not have been sufficient to break the head loose..........."
Of course, this might be right. I quit adding tension when I observed the head's front pull-point (non-technical term there) starting to bend somewhat. At the same time, the engine was lifting upwards.

How I'm using the engine hoist: Chain fed through each pull-point and attached to the hoist's central arm/hook. Seems like a reasonable method...

I'll be back on this project tomorrow morning. Oh yeah, picked-up a 4.5 lb. sledge yesterday to persuade that head if necessary:fork_off:

I will, of course, exercise care if I gotta use it w/the piece of wood.
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  #14  
Old 03-03-2007, 11:54 AM
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Cylinder head released from block!

Once again, placed some tension on the head using the hoist. Then, held the block of wood at several points on the manifold side while striking it w/the 4.5 lb. sledge. It took about 12 moderate strikes until the head popped free
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  #15  
Old 03-03-2007, 03:33 PM
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The old saying......

.....if all else fails, get a bigger hammer......

Glad everything worked out for you.......

SB

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