617 head removal - PeachParts Mercedes-Benz Forum

Lonesome 300CD · #1 02-24-2007, 02:42 PM

I've got an 84 300CD Turbo. Last week while replacing the valve seals one of the guides lifted up with the seal. After reading through some of the other forum posts I've discovered that I need to pull the head and take this to a good machanic to fix. Kicking myself now for this because the car was running great before I started, just burning a little more oil than I thought it should and embarassing me when I'd start it up if it had been sitting for more than a couple of hours.

Anyway I'm a bit new at this and am looking for some guidance about removing the head. Where I'm at now is as deep into an engine as I've ever gotten, so please don't worry about offending me by being too simplistic. Assume I know nothing....

I've got a guy to fix this when I get the head removed, but if anybody can recommend someone in the seattle area who they believe would do a good job, I'd appreciate the recommendation.

Thanks

Mustang_man298 · #2 02-24-2007, 02:51 PM

Quote:

Originally Posted by Lonesome 300CD

Kicking myself now for this because the car was running great before I started

Kick yourself? No, you should be THANKING yourself! You just caught & prevented a major problem from happening as it was beginning to form, before it had a chance to do serious expensive damage to the engine.

The biggest thing with pulling the head is making sure to keep the timing chain held up with a bungee or something, other than that its just removing parts from the head and then the head itself, the head bolts require a tool that resembles a Torx driver, except is 12 point, like the inside of a socket.

Lonesome 300CD · #3 02-24-2007, 03:06 PM

Thanks for response. Any precautions with respect to timing and keeping things lined up? What about the camshaft, do I have to remove that separately, also, do I have to remove the valves, valve springs etc?

vstech · #4 02-24-2007, 08:48 PM

Quote:

Originally Posted by Mustang_man298

the head bolts require a tool that resembles a Torx driver, except is 12 point, like the inside of a socket.

if you have a 79 or later, it's 12 point, but not like the inside of a socket, the points have a different angle. it's a "triple square" not a "double hex" I believe they can be gotten at autozone, but I got mine from a mac truck tool reseller. 4" long hardened impact 1/2" drive socket. about 20.00

if you have an old 79 or earlier, the head bolts are simple allen socket.
John

TheDon · #5 02-24-2007, 09:04 PM

Quote:

Originally Posted by Mustang_man298

The biggest thing with pulling the head is making sure to keep the timing chain held up with a bungee or something

we discussed this a few weeks ago.. Brian Carlton can probably back me up on this claim. The tensioner and injection pump gear will hold the chain in place so you can just lay the lengths of chain on their respective sides of the block..

GRIESL · #6 02-24-2007, 10:06 PM

Quote:

Originally Posted by TheDon

we discussed this a few weeks ago.. Brian Carlton can probably back me up on this claim. The tensioner and injection pump gear will hold the chain in place so you can just lay the lengths of chain on their respective sides of the block..

That does seem to be true--just did a head removal and laid the chain down. I also rotated the engine backward and forward (I know, I can't believe I'm admitting to that), and the chain didn't skip teeth down below(although I did have tension applied to the chain then by hanging it with a bungee cord from the hood, but I still wouldn't recommend what I did).

You have got to get the FSM. At least the pdf for the head removal. It's really not that hard if you follow the manual and ask for help on this forum before you do something stupid (like me--but heck the car is put back together and runs damned good!).

You should mark the cam gear and chain with a paint mark, and, yes, the cam has to come out mainly because the bolts holding the towers to the head also hold the head to the engine. Here's probably one of the most important pieces of information that I should have asked about prior to fu^$#ing some stuff up. When removing and installing the rockers, there is one position of the cam for each where they will easily pop out and in. Also, I would definitely recommend leaving manifolds on and pulling the head with a hoist. First, I could not get the turbo bolts off, and second, it's a whole lot easier pulling 20year stuck on bolts when the thing is on a bench or hanging from a hoist. Oh, last little tidbit--when removing cam, block it in the back with like some folded up cardboard. When you pop that bolt off the front, it'll definitely slide back if not blocked off and you'll see that thrust washer drop into that black hole where the timing chain resides. If anything falls down there and can't be retrieved, the engine has to come out. Oops, one last, last little tidbit--don't forget to unscrew that little bracket on the back of the head that holds down the oil feeder line to the turbo. Yikes, damn near pulled it loose from the oil filter housing before I figured out what was fighting against the hoist. Good luck.

PS: You should not consider yourself unlucky as suggested before. If that guide came loose with what you were doing, it was sure to go at some point under regular driving conditions. I've never seen the results of a guide coming loose, but I can only imagine that major valve and cam damage would be the minimum. You should consider yourself lucky. Besides, now the car gets a valve job.

sailor15015 · #7 02-24-2007, 11:03 PM

Quote:

Originally Posted by TheDon

we discussed this a few weeks ago.. Brian Carlton can probably back me up on this claim. The tensioner and injection pump gear will hold the chain in place so you can just lay the lengths of chain on their respective sides of the block..

Ditto. I dropped the chain numerous times when I was having the head work done on my engine and everything lined back up when I reinstalled everything. Of course, I had the luxury of having the engine out and in my garage so it wouldn't have been a big deal if it had come off the sprocket, but I wouldn't freak if you drop the chain. Get yourself a Haynes manual and the FSM. The Haynes does a good job of giving you step-by-step directions. That's what I used to remove it. I used the FSM cd for odd torque values that weren't in the Haynes. Its really not a bad job.

Lonesome 300CD · #8 02-24-2007, 11:38 PM

Thanks for the advice everyone. I've been looking at purchasing the FSM for a while now, so it seems like now is as good a time as any, and I'll take a look at the Haynes manual as well.

Any recommendations for a mechanic/machinist in the seattle area where I can take this when I get it out? Also, what would recommend that I have done to this. Is just pressing on a new valve guide the answer, what other things should I be looking at while I've got this thing apart. I may do the timing chain, because I don't know the history of it and the cars got 270,000 miles. As I had said earlier, the car ran very well prior to me taking it apart so I'm not sure what else to look at.

bgkast · #9 02-25-2007, 12:17 AM

If you want to go whole hog think about ordering a rebuilt head from metric motors. (hold on to your wallet!)

Lonesome 300CD · #10 03-04-2007, 02:55 PM

Alright,
got started earlier this morning, but I'm having some trouble getting the turbo charger out. I can't get the connection to the exhaust loose. Any suggestions? I've been prying at the lip with a crow bar, but can't get it to budge. Any problems with me smaking the exhaust pipe with a with a piece of wood and a small sledge to break the seal?

Brian Carlton · #11 03-04-2007, 03:54 PM

Quote:

Originally Posted by Lonesome 300CD

Alright,
got started earlier this morning, but I'm having some trouble getting the turbo charger out. I can't get the connection to the exhaust loose. Any suggestions? I've been prying at the lip with a crow bar, but can't get it to budge. Any problems with me smaking the exhaust pipe with a with a piece of wood and a small sledge to break the seal?

Once the three nuts are off the flange, and the flange is pulled back, nothing holds the exhaust pipe to the turbo outlet. So, just whack it with a piece of wood........it'll come right off.

Lonesome 300CD · #12 03-04-2007, 04:36 PM

Thanks Brian, That's what I thought, but I was hesitant to start whacking away at the thing before I got some confirmation.

GRIESL · #13 03-04-2007, 08:19 PM

Quote:

Originally Posted by Lonesome 300CD

Alright,
got started earlier this morning, but I'm having some trouble getting the turbo charger out. I can't get the connection to the exhaust loose. Any suggestions? I've been prying at the lip with a crow bar, but can't get it to budge. Any problems with me smaking the exhaust pipe with a with a piece of wood and a small sledge to break the seal?

This is just me, but I'd leave turbo connected to manifolds and pull the head with manifolds attached. I had a bear of a time getting at all four turbo bolts. Maybe I'm lacking some kind of narrow bent wrench, but I could only get two to budge. So I reached down under the turbo and loosened up the bracket bolt down there and pulled it as one unit. Not hard to do as long as you have a hoist to pull it. Good luck!

MarkM · #14 03-13-2007, 07:06 AM

1. Watch out with the spacer ring (shim) between the front cam tower and the timing gear. If you don't hold onto it when you disassemble, the ring is very likely to fall into the timing chain compartment, and you may have to spend hours trying to find it and fish it out with a piece of wire....don't ask me how I know this!

2. The only "special tool" you will need to remove the head is a "shop made" extractor for pulling out the pin that holds the timing chain guide...you will see the head of the pin at the front of the head, and I think the threads are 5 mm...so you need a 5 mm bolt with a bunch of spacers...I use a combination of sockets and washers...as you tighten the bolt, it pulls the pin, and you need to remove the bolt and add spacers as the pin comes out.

3. Remove the turbo and the manifold as one unit...its a little easier...the lower bolt that attaches the turbo support to the block is a real PITA

4. You might find that to remove the manifold/turbo, you will need to push back the transmission filler tube...if you do this too much, you may distort the o ring which seals the tube where it enters the transmission case, causing a serious trans. fluid leak (again, don't ask me how I know this). With the head out, you will have better access to replace this o ring...very simple...remove the retainer bolt, pull out tube, replace o ring, re-install.

5. When you have the head off, you have access to a number of things that will be real easy to replace, if needed...such as, block heater, short hose between thermostat housing and water pump, coolant hoses at firewall, turbo drain grommet-seal & o rings, etc. ..not to mention head-related stuff...valves, glow plugs, etc.

Good Luck,

Mark