Cam towers
 

I'm looking into sourcing a head for a 603 but have noticed many have the cam and towers removed for whatever reason. I seem to recall when installing new or used cam towers additional machining is required before fitting bearings. I'm looking for experience and advise as my only experience has been working with already installed and working heads never had this need before.

There are no cam towers on a 603. The lower bearing is part of the head, the upper bearing is a cap. There are no replaceable bearings. Any head you're looking at should have the upper bearing cap, they're machined together with the head. If they're lacking the cap, move on to one that does.

I thought you were getting rid of that engine?

That engine is ghost my friend. I would use it for spare parts though.

Yes I was referring to cam caps. Just the head is toast and I have a week plus to make up my mind. It appears way easier to find a head for the 603 than the 602.

I'm pretty sure that engine is decent. I'd put the money into a used head and put in your car. 603 is a more powerful engine and these days in traffic with soccer mom SUVs that put out 250hp, I'd rather have every bit of power I can get

used heads are going for a premium if you add in machine time and the uncertainty of a used head being warped it's cheaper to go with a new head for the 603. New 602 heads are na and few used on the market.

I REALLY would like to find a good used turbo 602 head for sale...

I don't agree with this conclusion, but then I've got a nice #20 head I'd sell for $800. :)

The head I'm selling comes with camshaft and the matching bearing caps, it would need injectors (the latter inclined aka oblique injection type (NA 35 X), about $650 for rebuilts but one can get a used set for about $120 if patient and search around, and then get new nozzles and have Greazzer rebuild them for another $250 or so have a great set of injectors for about $400), and if I were installing I'd also replace the hydraulic lifters (INA are about $10 each I think for 12x so $120) but the old lifters are included with my used head. I think a local shop would pressure test and check for flat for around $200 or $300, and then the remaining cost would be shipping. This is assuming the valve guides are OK, probably have the shop check that and then install new seals, so another $50 or so for those parts.

My understanding is that the new 603 head is about $2k or $2500, and it is "bare" so you've got to provide and install injectors, pre-chambers, lifters, camshaft. One can re-use them from their old head, and pay a shop to install the pre-chambers. There will be some downtime for the car in this case.

Let's say one has time for shop work or DIY, and will go the most frugal route.

My used head:
$800 for the #20 head
$350 for shop work (pressure test, check for flat, check valve guides, new seals estimated cost of $50 included in the $350, assuming valve guides are good)
Re-use old lifters
Re-use either camshaft (mine or original on your car)
Re-use old glow plugs (I've got them for this head, inclined are different from vertical injection)
$120 Purchase used set of injectors
$200 set of new Monark or Bosio nozzles (This was $150 last time I bought a set about two years ago)
$120 for Greazzer to clean, test, and balance the set of injectors
$100 for shipping the head
------
$1700 total (I've rounded up from $1690).

New #22 head from MB:
$2000 for the "bare" head
Re-use old lifters
Re-use old camshaft
Re-use old pre-chambers, borrow tool(s) for free and install them yourself
Re-use old injectors, no testing or service by Greazzer
Re-use old glow plugs
------
$2000 total (is a new head really $2k, or are they more now? Assumption here...)

[not included in the above, cost will be required for either route so it is a wash: head gasket set, new head bolt set if used head bolts are too stretched]

Both choices have risk. Used head may fail test at machine shop, while installing used pre-chambers in new head may end up with bad seals and re-do or even worse a cracked pre-chamber. Used head may fail (crack) after installation, no warranty, but the new head would have a warranty. Old lifters may not perform well and you have some lifter knock. Old #7 camshaft on early OM603 has different profile than #11 camshaft on later OM603 with 3.5 liters so less power? Worn lobes on old camshaft. Old injectors may need to be cleaned / tested / balanced. Old glow plugs may be bad or fail shortly after installation. Not all folks are capable of DIY so paying a independent shop to do this gets expensive fast, and they may not be willing to install a used head they didn't provide.

Replacing a head is a LOT of work in my opinion, so it really becomes a personal choice about cost vs. risk vs. time.

More frugal options are available! Pick-n-pull yards charge about $200 for a head, if you can find one. I pressure tested the head currently installed on my 124.193 myself, totally redneck fashion, by rigging a way to pressurize the exhaust manifold and heating a barrel cut in half and filled with water with the head / manifold inside and watching for leaks passing air from exhaust manifold side to cooling passages.

Max thats a comprehensive and impressive summary. New bare no.22 heads seem to be all over the map anywhere from $1100 the source I will not disclose for a while since only 2 are remaining in stock all the way up to $3650. Even fully dressed heads are less prechambers and injectors.

We have 12 machine shops 11 have never touched a mercedes head and half of those don't know what pre chamber is but all are willing to skim it. The one shop family operated for 30 years recalls doing a 60x head that ended up in litigation. He would pressure test, skim it .007 in, insert new guides, grind the valves and seats provided I remove and deal with the pre chambers all for $850. Hopefully that explains a bit of my reluctance going the used head route.

I did find several used heads $450 no caps (no. 20) or pre chambers, $600 with caps and prechambers (no.20) and $1100 complete with prechambers injectors and injection lines (no. 17). All would require machining and shipping. So I would be looking at $2100 minimum. The same shop who is selling the new bare head also has a head loaded less prechambers for $1800 landed at my door.

It been giving me kinda a headache thinking about it all. As far as injectors go I'm good to pop and balance whatever and think I have new nozzels somewhere. I do like the idea of the updated cam.

I know that pain. I bought one used #17 head, but then had trouble getting the NA 35 X injectors for it. While looking, I found a #20 for sale "cheap" for $200 with injectors, turned out they were the older style (NA 36 X) as someone had converted to the older pre-chambers. Took that one to local machine shop for pressure test (good) and then flat check (good) and then had them install new valve guides and seals. Installed, had low compression and rough running, found that two lifter bores were trashed. Also had indications of cracked head - pressurized upper radiator hose. Don't know if I did that or shop didn't clean out the oil passages, so I pulled that off and turned it in for scrap, red-neck-pressure-tested the #17 head, installed that and found some injectors, had some difficulty getting everything sorted but now she's purring just fine.

Shop local to me did the pressure testing on the first head.