Rebuilding a 1984 head to replace the cracked head on my 1982 300SD.

What machine work would you suggest to have done on the head ?
And what components would you replace ?
Would you install an offset woodruff key to the timing gear to compensate for timing chain stretch ?

Also I can seem to find the specifications on how far down into the head the intake and exhaust valve guides should be pressed.
Does anyone know ?
Thank You.

if you are replacing the head, I'd replace the chain as well. valve guides should be installed by a machine shop, they will know how deep ot install them. aside from that, I'd change the valve seals, and install the sucker.

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My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
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Installing a new timing chain sounds like a good idea.
I will add that to the list.

Dont think I like the idea of trusting a machine shop to get the valve guides pressed in correctly without depth specifications.

I have trust issues...

Anyone know how far the valve guides are supposed to be seated into the head ?

I should have measured before pulling them out.
Guess I could measure the guides in another head.

Do you have any FSM for the engine? If not here is a source for them.

Mercedes Benz Manuals | Service Manual Engine 617.95 Turbo Diesel

Untitled Document

The second link is an online 2 disk FSM from MB.


Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Unless you have a full automotive machine shop, it is costly to DIY.

* Valve seat tools.
* Valve grinder USED
* Valve Guide Knurling & Resizing Tools.
* There are other special tools required.


.

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

Remember it is best to freeze the new guides and preheat the head before driving the new guides in. Since you need a decent pin reamer to size them afterwards as hunter says doing it at home builds up cost wise.

That said it is suprising some member has not set up a service to do these heads properly.

I believe it is "1960mog" that rebuilt his engine in his shop.
He did say "Send me your sick and wounded". think he lives in Las Vegas.



Found the thread:

617 Engine Problem


Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

I would like to have a competent machine shop look over my work.
But I dont like to trust people by not having the information myself.

Also I do not see the need for all of the tools you have listed in this post.

Has it been you experience that new guides are off enough to necessitate grinding the mating surfaces of the valves and the valve seats beyond what can be done with simple valve lapping and grinding tools like the good old suction cup stick and lapping / grinding paste ?

Guess I will find out. Maybe I will get lucky.

Thank You.
I am sure these links will come in very handy !

If you change the guides you will have to ream them. The internal diameter of them is purposly undersized. You will have to have a cutting stones with a stem that goes into the newly reamed valve guide to reorient the seat alignment if off with wear as well or the new alignment centre of the replaced reamed guide.

I am all for saving money where practical and will attempt things sometimes that others will not. In this case there is just too much work involved to have it all go wrong.

Do as you will of course. Not trying to burst your bubble. In a simular situation I could drive The guides in and have a good auto machine shop ream them. Do the seats and turn the valves.Salvaging as many of the valves as possible.

Take it all home and put the head back together. This is about as cheap a way I could manage if I had too. Anything less is asking for issues I believe in your instance. Did you check the old intake valve guides for wear before driving them out? Not all may have needed changed. If they were all badly worn those seats are going to really need attention anyways as well.

What advice I post on site is not meant to do other than help people where it is possible. I certainly do not know that much. Many of them help me as well in return. I am not trying to challenge your beliefs either. Think it over.

It is not rocket science to do a valve job. At the same time there are minumin requirements. Some approaches you are mentioning did apply perhaps to cars of the nineteen twenties.

Thank you
This seems like the exact kind of information I need to do this job well.
I am glad you posted this.

What you are saying is the new valve guides are made with a slightly smaller inside diameter than the outside diameter of the valve stems that go into them ?
And that the guides need to be reamed out to fit the stems ?
And that the reaming needs to be done in a way that aligns the valve with the valve seat ?

The odds of any random machine shop doing the job on the head and having that result be acceptable in terms of compression and oil consumption are practically zero. The tolerances on the head are critical and no local yokel wants to make the required effort to do the proper job, if they even have a manual to show the required tolerances.

Send the head to this place:

Mercedes Rebuit Engines

If you don't you'll surely regret it. Many others on here have.

Valve, guide, and seat's are standard jobs.
Any performance (race engine) machine shop can do this job correctly.
Print off the specifications, put each page in a clear sleeve, put it all in a binder to go with the cylinder head.

Visit various shops, have them review the specifications (before bringing in the head).
Most shops will appreciate having the SPEC to review + will clearly answer yes/no.
If you don't feel happy = go elsewhere.

Don't allow them to re-surface the cylinder head, often the hacks will take to much off.
IMO: A warped OM617 cylinder head is "for me" not worth re-surfacing, a good used replacement is cheaper, even after new valve, seat, guides.

.

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

Correct.

.

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

I agree. Finding a competent machine shop is extremely hard.
And is part of why I want to do the work myself if possible.

I may be wrong but even the guys on the page you gave a link to seem to have the same head listed twice for two different prices.
One is listed as 300D 617 for $920.00
And a second listed as 300SD 617 for 1,090.00

Mercedes Rebuilt Engines