Head Removal Advice

[johnk]

Considering everyone's advice in my previous thread - Replacing Valve Seals, I believed I am going to remove the head and send it in to be rebuilt rather than just replacing the seals first. I used to do a lot more mechanical work when cars (and my life) were much simpler. Now that I have a simpler car I would like to try it again. I overhauled my 1972 220D myself, but that was over thirty years ago.

The instructions in the Haynes book for a head removal seem quite simple to follow. However it does not seem to say anything about what to has to be aligned before I remove the head. I remember reading somewhere the rotor needs to be pointing to the number one plug wire and the number one cylinder has to be at top dead center. Can someone tell me if this is correct, and if so, how do I tell if the cylinder is at TDC when the head is on? Is there anything else I should consider as well?

I am sorry to ask such basic questions but this bean counter is really looking forward to getting his hands dirty again!

I appreciate everyone's help.

John K

[stickandrudderman]

In my early career I adopted a policy of marking everything with paint and then looking for the proper marks. That way even if I couldn't find the proper marks or the necessary data I still had a datum to work from.

[Rolf-Dieter ✝︎]

John, have you checked the Tech Manual? ----> http://www.sl113.org/wiki/Engine/CylinderHead

[ja17]

Hello John,

Don't cut yourself short, this will be a challenging project.

First consider you might want to keep the injection timing, ignition timing, distributor timing and valve timing in sync before disconnecting everything. If you first set the engine to TDC of compression stroke #1. Make sure the engine is on the compression stroke (both front camshaft lobes pointing basically upward). Now take the distributor cap off and note the position of the rotor. Mark its position on the rim of the distributor (good advice from Stick). If the distributor has been correctly indexed during previous repairs, you will find that the rotor is pointing to a slash mark on the distributor rim.

Does your engine have AC ?

In any case, I start by removing the hood. Read up on this in the tech manual. Its fairly easy and makes everything easier. Ask questions if you need more info. Cap or cover your injectors and the injection fittings to keep dirt out of the system.

Some other tips......Drain the coolant first,  you do not have to split the timing chain unless you are replacing it, I leave the exhaust manifolds hooked to the front pipes., jack up the front pipes and slide the head off after everything is un-hooked and ready. Save hours of time messing with rusty and stuck front pipe/manifold hardware........, be careful with the delicate capillary tube for the temperature gauge, review the location of the two  hard to find 6mm allen bolts down in the chain gallery (front),  clean the threads of the head bolts and run a tap down the holes to clean them up. I use a 14mm swivel socket on a long extension to get to the intake manifold bolts easily after the heat shield is removed. Don't miss the large metal air line going to the bottom of the intake cold start valve. Plan on checking the very critical "vertical timing gear" and its thrust bushing. This is much easier with the head off. Keep us up to date on your progress. Add much more difficulty if  you have AC. consider installing a new water pump and timing chain while you have ever thing apart. Keep us up to date on your progress or problems.

Joe Alexander (ja17)
Blacklick, Ohio

[johnk]

Thanks everyone,

This is great advice and all makes sense to me. I really like the idea of leaving the exhaust manifold connected to the head in addition to the important things to watch out for and mark. The car does not have air, luckily for this project based upon what I have read to far. I will finish reading everything I can find in the tech manual as well before I dig in. Definitely will replace as much as I can as I don't like doing things twice to save a few bucks. I am sure I will have more questions as I go.

Joe I am going to be in Columbus on business the last week of April. Would it be OK if I swing by to introduce myself and say hello?

John K

[ja17]

Hello John,

I leave the exhaust manifolds attached to the front pipes. They basically stay on the pipes when the head is pulled.  Yes, by all means stop by for a visit. Just email or call a day or two before so I am around when you are in town.

[Shvegel]

John,
I second Joe's warning about the temp sensor bulb capillary tube and the "Hidden" allen screw.  If memory serves the screw is on the tensioner side of the chain gallery covered with a pool of oil.  There is a really good machinist in Cleveland that I have not dealt with in a few years. If you need a shop let me know and I will see if he is still in business.  He did a BMW head for me and it turned out beautifully.  Otherwise there is a pretty high end guy near you that fixes Porsches etc called Autobahn Extremists.  He might know of someone more local.

Found the machinist:

Metals Crankshaft Grinding Co
1435 East 45th Street
Cleveland, OH 44103
(216) 431-5778

[johnk]

Thanks Shvegel,

I am working with a close friend that has run a repair facility as part of his used car sales for 30 years. If he does not know of someone local that can handle these aluminum Mercedes heads I will definitely need your recommendation. He has a 190e head out right now being rebuilt but I don't know where and what the shop's capabilities are.

[johnk]

Joe,
Sorry I meant to type leave them attached to the exhaust rather than the head. Hopefully I am better at following directions than retyping them.

Great would love to meet you but don't want to take up too much of your time. I am driving down Monday afternoon/evening the 28th of April, and the convention is over around noon on May 1st. I can stop by on my way down or back up whatever works best for you. I will get in touch with you the Friday before.

John

[Novamonte]

One more thing learned from previous experience:  there is a bolt (the "special bolt") on the left side of the chain gallery that holds the servo fluid reservoir bracket. This bolt has a second purpose. Its rounded tip holds the cam chain in position on the sprocket that drives the distributor and the FIP. When you have removed the bracket, make sure to put that bolt back before turning the  engine to prevent the chain from slipping. Can save hours of work to re-time FIP and ignition.

[ja17]

Good advice Novamonte!

[johnk]

I love this. I am getting advice from around the world on how to do it right!

Thank you Navamonte!