about to reinstall 603 head, tips?
 

ok, so i got the head back from the machine shop. it was refaced i think to the absolute limit. all the pits where water might seep in to the cylinders were filled, valves and guides are all new.

i removed the head myself for the first time, so this will also be my first reinstallation. anything i should be wary of? do i put sealant on the headgasket or is it not necessary?

i cleaned the top of the pistons. i noticed that when i removed the head some of the carbon deposits and some crud fell into the cylinders, i vacuumed all that can be vacuumed but looking in with a flashlight i see some made it between the piston and the walls, will those be burned during combustion?

tips and tricks needed. :)

Do you have a manual to guide you? The reason I ask is that you mention sealant for the head gasket. Cam tower tightening sequence is very important!

If you need to replace the thermostat, do it before you reinstall the head.

Sixto
95 S420
87 300SDL

carbon
 

the small amount of carbon left should blow out. i believe that sealand on the head gasket is a matter of opinion. some say yes some no. i believe my machinist does. he uses a spray on type and when i did my own i used the same stuff. i believe it was prestone brand. if nobody else has a suggestion here i will call him and ask what brand for sure.

all i have is a haynes manual, it helped a lot during the disassembly. i am aware of the cam tightening sequence, upon disassembly i realized its importance. :sun_smile

no mention was made about putting sealant so i assume its not needed. what kind of prep work do i have to do? should i lightly coat the mating surfaces with oil or do i dry them out completely?

and do i oil the cylinders? the engine has been sitting for nearly a month so all the oil is in the pan.

before i fire it up (when i get there), is there a way to prime the oil pump or something? do i rotate the engine manualy (before installing the injectors) to get the oil to circulate?

Haynes manuals are they explicit about tightening sequence? Look at the Reinz web site for info on the 603 headbolt tightening procedure I believe its there, it works. I remember someone commenting on a MB manual that mis-described the cam removal procedure. You can crack the camshaft if you get off on removing and replacing the cam tie downs.

You're going to crank it over quite a lot to purge the air in the fuel lines, too bad they didn't put a manual primer pump in these engines :( and during that time the oil will pump up good. I would squirt oil in the cylinders anyhow.
I have a preference for Reinz gaskets, I'd throw out an OE or Elring gasket and use Reinz if I were in your shoes. No sealant either.
Are you replacing the lifters?

Dang! I thought I had a taker for that Elring gasket in the garage :)

Sixto
95 S420
87 300SDL

One thing I thought of after installing the head was to put a half cup of 0W-40 (flows like coffee when cold) in each cylinder and see how long it takes to drain. Would this give some indication of ring condition?

In retrospect you should have lubed and wrapped the parts you took off the engine. I lay parts in plastic wrap, slather with oil or WD-40 and cover with more plastic wrap. For most people this probably isn't necessary but I manage to stretch jobs like a 20 hour head R&R over 4 months :/

When the block sat with the head off I poured oil into each cylinder and every few days wet the cylinder walls. I sucked out the oil with a TopSider before installing the head.

Sixto
95 S420
87 300SDL

i'm using a victor reinz head gasket, at the time i didn't know what to get... it was the only one they had available, whew!

initially i wrapped the cam, it was the machine shop that let it get exposed. the haynes does indeed have the cam removal/tightening sequence as well as the head sequences.

if i do the oil leakdown thing what amount and how long should they drain ideally?

what about the prep prior to gasket installation? do i apply a coating of oil or do they go in dry?

And no, i didn't replace the lifters, should i? i'm a little over budget right now, if i HAVE to then i will. I understand that i have to prime the lifters, is it as simple as submerging them in oil and pressing on them till they get packed with oil?

lube
 

i would use white assembly lube on the cam during assembly. not essential but insurance.

locry, the head gasket goes on dry. To prep it, just make sure the two surfaces are very clean and bone dry.

Thanks
David

so bone dry it is... thanks pardner!

Victor Reinz may be an original equipment manufactuer, but I'd used the real Mercedes Gasket on the head. It has been updated around seven times to address sealing problems. The latest edition has got it right. Just to give you something to scratch your head about, did your machine shop shim the prechambers to match the head shaving as directed in the factory manual? Also you' want to double check and probably adjust cam timing and pump timing as removing material from the head retards both.

Lifters generally keep the oil in them after you ran it last, but now is a prime time to check each one. A weak lifter will have little resistance when pushing the center contact inward. A good one will be hard to push in.

I didn't use any lubes, or sealant when replacing my head gasket on my 603. The last stage of torquing the head bolts will make loud creaking sounds, as you might hear if you were over tightening, don't worry about that!

But you might want to measure the head bolts before you re-install them. The 603 uses stretch-to-yield bolts and they must be replaced if they have reached a maximum length.

There's a Haynes manual covering the OM603? First time I have heard of that. What manual is it exactly?

thanks for all the tips guys!i'll have to double check if they did indeed shim the pre chambers, how do i check this on my own without removing the prechamber(which i can't)? i can just measure the protrusion, anybody have specs for this?

the haynes manual that i have is for a mercedes w124, it includes all the engine variations. it vdoes have all the numerical specs listed, though i'll have to check if it has the prechamber protrusion number.

about the lifters: they are very easy to depress, all of 'em are, i guess they've been drained of oil, they can be primed manualy right?
IF ever, is it bad to run bad lifters? does it do physical damage or just the performance?

btw, while i was doing initial prep on the block i noticed that while cleaning the pistons that i could move them a bit side-to-side(back-to-front blockwise) is this normal?
and when i vacuumed the block surface, a bit of oil was seeping up between the cylinder sleeves and the block(not the piston/sleeve), i could see a very slight gap(oil) batween the sleeve and the block when i look hard enough, this normal?

Bump...

Yes, there will be a tiny bit of play in piston-to-cylinder movement, as it is the rings that make all the contact normally.

If you submerge the lifters in a pail of oil, and depress the lifter with a push stick, or whatever, you can pump up oil into them. If you have dry lifters installed before starting the engine, it would run very rough until each lifter filled with oil, a few seconds, but I don't think you would harm anything doing such!

The protrusion should be 7.6-8.1 mm.

If greater than this value, you must use spacer rings. They make three thickness, .3mm, .6mm, and 1.0 mm.

I have just been through the head replacement :sad: . The fact that the head was machined means your timing may be off some when you re-install everything :worried: . Pay close attention to cam timing and subseuqently the injection pump. I recommend rotating everything at least twice (in the forward direction only) and checking the timing each rotation. you should check the injection pump timing at this point also. (through governor inspection plug 15 deg btdc, there are posts that outline it better) the car will start and run with the timing off at the cam and pump but rough and loud with lost of smoke :shocked: . it is very important also to torque the cam in the proper sequence ( and the cam sprocket :mad: , long, expensive story) If you need any other hints, you can pm and/or call me.

i checked the protrusion and its at 8mm. still safe.

i'm relieved to know about the piston movement being normal, i thought that maybe i also needed a bottom end rebuild. $$$

the timing WILL be off after a head shave? i'll do a search on how to check timing then,... can i do this before i fire up the engine?

thanks again guys i REALLY appreciate all the help as this is my first attempt with heads. :)

15* ATDC

It's a timing reference, not a timing spec.

Sixto
95 S420
87 300SDL

ok, so 15* ATDC at the crank? i should see the mark on the inspection hole at the pump?

oops :shame:

had a small block on the brain with BTDC

Correct. Through the hole where you would screw in the "inj. pump lock tool" (may come in handy for setting the pump timing, check with GSXR's posts on inj pump timing) you should see a grove or "V" cut in the edge of the governor flywheel. If doing this visually you will need a light and mirror, and maybe some air to blow any oil off the indicator for easier location.