price of cylinder head rebuild?
 

How much might it cost me at a machine shop to have the head completely rebuilt? I could strip it down myself, I do have the tools, but is it worth it and wouldn't I want them to do the seats at the same time? Am I making sense? If not please let me know.
Thanks
David

It would help if we had a year, model, and engine that you were referring to? :confused:

1987 300D. Someone said they would sell me a head but I wanted to know just a round figure on how much it would cost. It has the L6 aluminum head. Do the valves on these engines last long? Would I have to replace any valves? I don't know the mileage yet but wouldn't I replace the valve springs too? I don't know a lot about these kind of things. I just have my uncle or dad help me with this kind of stuff.
Thanks
David

Valve springs normally last the life of the car or engine - 500-750kmi. The valves can last that long too, but check them while the head is apart. They're expensive so you don't replace them unless it's necessary.

A new head comes bare with no valves, springs, lifters - only the guides and seats. At the dealer it iwll be over $2000 for a new head. Best price online is about $1600 that I know of. Most salvage yards want $800-$1200 for a used one. The yard in NY has one for $500 per my other post. Make sure it's not cracked, as shown in my other photos... that's how most of them fail in the first place!


Good luck,

When the cracks in my original 603 head advanced to where the car was undriveable, I reused all the loose hardware except for two exhaust valves. I replaced the lash adjusters because I couldn't identify the noise one/s. Ended up with a noisy one in the new set so I'm back to square one.

Did you verify the history of the head? It's kind of strange that someone would have a head to sell when it's usually the head that's the first to go on these engines. Let me know when you're tired of me saying that :)

Sixto
91 300SE
87 300SDL
83 300SD

Sixto,

You have 12 new lifters and one is still noisy? Really? Wow - what oil are you using? My new 12 are silent! (mmmmmm.) Even my other car, with unknown age but assumed stock with 246kmi, are quiet with Delvac-1. The test involves yanking the valve cover with the engine hot and pressing on each lifter as the cam hits base circle (no pressure from cam on lifter). It should be rock solid. If they "squish" down, the lifter is bleeding down and needs replacement. Of my old set, 5 failed, and 7 were OK. I changed them all since i was putting on a new head and didn't want to re-do work in the future!

I didn't think to check until the head was apart :(

I ran Delo 400 for a 1000 miles to seat everything and sop up whatever contaminants got into the sump during the 4 months the car sat decapitated. It's been on Mobil1 15W-50 for the last 2000 miles.

Sixto
91 300SE
87 300SDL
83 300SD

Well shoot. Wait until your next M-1 oil change. If still no improvement, yank the cover off & do the test. The cam stays intact, it's not too hard to do. If they're all solid, then you get to suffer with the noise (design flaw - you're not the first one to have this happen.) :(

So what would it cost to have a machine shop grind it down. Can they do the grinding without the valves intact? I mean the valve seats? Could I do the valve guides myself? Or would it take special tools other than spring compressors, etc.?\
Thanks
David

The surface only gets milled if it's out of spec - not common. If it needs that, the prechamber protrusion must be measured & if they needs adjustment, it will cost ~$100 for the special shims. Valve seats only need grinding if they're damaged. Otherwise they can be lapped, I think, no big deal. Guides don't get replaced unless they're out of spec. Most of the stuff you're asking about is not standard "rebuild" on the 603 head, it's all specialty stuff that gets replaced as necessary due to the high cost. You want to buy a GOOD used head, from a salvage yard with a WARRANTY, so you can return it if it needs any of the things you're asking about!

Don't even think about doing any of this yourself without the factory OM603 engine manual (on the CD-ROM sets or the paper version). All the information on procedures is in there.

Want,

You probably don't want to hear this but with the little you seem to know about rebuilding heads, you should have all the work done by a competent shop familiar with MB aluminum heads.

You probably don't have the tools necessary to do the work yourself either.

P E H

I'm with PEH. If you want to do any portion of that head re-build yourself, put your energy into finding a shop that understands the product and will do a quality job for you. Chances are, if you were able to do some small part of it yourself, your efforts may only hinder the guy in the shop. Besides, if he's good he will need the valves and springs in place in order to properly access other things like guides & valve stems. You should expect to pay $125 or more for labor + the price of any guides, valves, or ... If the engine was overheated, the head may be warped and/or cracked. If you have the bottom surface of a warped head machined, the camshaft might bind because the top will still be warped. Either of these might justify buying a used head. Most used units are warranted to be crack/warp free, and therefore should then be taken to the shop to be re-build or at least checked out.

That reminds me. Even the head R&R procedure on this engine is not a DIY for just anyone. It requries several special tools which must be purchased (~$200), and some very specific procedures (which are all described in the FACTORY service manual). You don't just unbolt the head and bolt a new one on. This ain't a Chevy small block...!
:eek:

When I replaced the head of the SDL, I didn't use any tool that I didn't get at Sears or Home Depot. I got the head down to casting, valves, springs and prechambers and took it and the new head to the machine shop.

From what I hear, pulling prechambers is not for mortals. No way I'd attempt that even with prechamber tools.

Sixto
91 300SE
87 300SDL
83 300SD

The tools I referred to include both prechamber tools, the IP lock tool, 12pt internal drive for the head bolts, and the tools to R&R the fan clutch. The rail pin puller is handy too. Also needed are a torque wrench (or two) and a generous assortment of hand tools. Some of these can be worked around but it WILL take you twice as long for those particular jobs w/o the proper tools! And yes, pulling the prechambers ain't fun. Guess it made me immortal though - cool! :cool: :cool: