Oh, it's a one in two chance since the crank only registers TDC when #1 and #6 are at TDC.

Sixto
87 300D

This engine is finally going back together! THe head is on and torqued. The timing chain is on, as well as the water pump, power steering pump, crank pulley. and the list is getting longer every day!

The marks are lined up according to the manual for timing and the RIV!

I must say that it feels good to see my project moving forward after all the heartbreak of finding that the head was junk and all the other little parts that needed to be located.

Does anybody have any tips on the break in for a overhauled engine?

Once again thank you all for sharing your knowledge and experiences.



Eddie E.
300 SDL 325k and looking for more!

Hello all, I have run this engine for its first 500 mi since overhaul and it sounds better and better. Injection pump started to leak fuel from the delivery valves so I changed the seals, then started to leak oil. I located a used replacement with less miles and installed it. the car runs much better, I also reset the timing. Now I have a sound that is like a sewing machine at the front of the engine. Have read in the forum about timing belt tensioners, pulley, and spring and suspect that is the cause. The only parts that I did not replace during the overhaul....go figure.

Well I plan on replacing it and hope the noise goes away. Will let you know how it goes.

I bought a parts motor without a head on it(where I got the replacement IP) I am going to build up a short block and need two used pistons. Number three and four appear to have small chips out of them.

What would cause this? they look smooth around the edges. not like there had been contact between a valve and the piston which would make severe damage to the top of the piston.

Anybody have any good used pistons for sale?

Eddie e.
87 300SDL
316k + AND CHALKING UP MORE!

Call Phil -- He can get you a great deal on new Mahle pistons. Tell him Bill from NC sent you.

__________________
1998 E300 +310,000K
1996 E300 +460,000K

The prechamber can disintegrate and drop bits on the piston. Within the last couple of weeks, someone posted pictures of the result of such an occurrence in a 617.

Sixto
87 300D

Hello all,

I have put almost 3K on the odometer.

500 miles, First failure was the alternator pulley, there fore I lost the accessory drive belt. Immediate shut down saved the motor from overheat. I would recommend to all to change out alternator pully if you have 200K on yours. Its cheap and easy fix that will give you peace of mind.

Next failure, head gasket between #1 cylinder and timing chain housing. I think I might get lucky here because there was no oil in the coolant or vice versa. No pressure build up in the cooling system either. I think this thing was slowly failing because it gradualy started smoking over a weeks time and then whammo! I could not see the cars behind me in traffic for all the smoke. Again immediately pulled over and shut down. No overheat experienced. The car has sit for 3 days now. I plan to loosen and retorque the head to see if any of the bolts may have worked loose or stretched.

Any other suggestions?

The fun never ends!....................................


FLYWULF

You should at least check that the head bolts are within stretch limit before retorquing.

Don't forget the bolts into the timing chain cover and ones by the power steering pump bracket.

There are bolts covered by the cam towers so the cam has to come off. There is a sequence to loosening and tightening the cam towers so you don't snap the cam.

I'm 99% sure you will see no improvement in the oil front from retorquing the head bolts.

Sixto
87 300D

If you have any other suggestions, I would love to hear them. Do you think I lost a oil ring? Lost a head gasket? Lost another head? Lost the block? cracked a cylinder? Maybe I Lost my mind throwing this much money at this car?

The engine runs fine when it is cold and the turbo does not run. Starts smoking when warmed up.

FlyWulf

Hello again all,

I have the valve cover off and can see the head gasket around the front of the motor is not altered. The torque on the bolts is good.

The crankcase is getting pressurized and blowing oil vapor through the crankcase vent and into the intake. The vent at the back of the valve cover is also blowing vapor.

Sixto, what do you think? What part of the head cracking would cause this?

Maybe the patron saint of diesel will go easy on me (this time around!) and it will turn out to be only a set of rings or a valve guide seal.

............................................................ .........

FlyWulf

This is a picture of DaveM/gsxr's 602 head gasket failure -

http://www.w124performance.com/images/OM602_head/gasket_failure1.jpg

How did you verify an intact head gasket with only the valve cover off? Did you run the engine and not observe compression leaking into the timing chain area? This is a common failure. Typically accompanied by a breach in the seal around the oil feel line to the head which causes an oil leak in the #1 exhaust runner.

If you don't see oil in the coolant and there isn't pressure in the upper radiator hose after the car sits for 12 hours, I wouldn't worry about head cracks. It is a #17 or later head, right?

Sixto
87 300D

Oh, it's a fresh gasket. Hmm... not sure what else it could be. Time for a compression and leak down test.

Sixto
87 300D

The head is a reconditioned #22. Installed a year ago with a new head gasket.

What I did is just look at the gasket and mating surface between the head and the block to see if the gasket had pushed out. Also looked down the air pipe towards the turbocompressor. Saw very little oil, just a little soot from the EGR.

I read one thread that suggested a turbo oil seal failure could cause this.
Seems plausible but unlikely because in the past I looked through the oil cap port on the valve cover and never saw the mist inside the crankcase the way I do now.

Thanks sixto, I think your right. I am gonna do a compression test and leakdown test next.

Keeping my fingers crossed.

FlyWulf

Hello again,

Got 3K miles out of the last rebuild, take 2

Completed the compression and leak down check. Great compression on cyl's 1thru 5, 6 a little low and it leaked down rapidly. Put oil in the #6 cyl and the compressioin came right up.

Motor out of car and completely dissassembled. Sent the block out to be sleeved this time. The machinist matched the cyl bore to each piston. Says it is the way to go.

Also found broken springs under compression and oil scraper rings. New rings on order.

Also found valve contact on the #1 and #3 pistons. Looks like the valve embeded itself into the piston approximately .5 mil. How would this happen? Timing problem? Incorrect valves installed at those two locations maybe. Block deck lowered during a previous rebuild? The pistons never rose above the block deck as I remember. Are there any shims used in the valve assembly? I need to figure this one out before putting this head back on.

Has anyone seen the valve contact happen before on the OM603?

Cheers,

FlyWulf

The pistons do rise above the deck by something like 0.75mm IIRC. That's the basis of measuring rod bending in 3.5s. There's the thickness of the gasket and reliefs in the piston to prevent valve contact.

Contact might have occurred if the cam wasn't held at TDC as it was torqued onto the head.

Sixto
87 300D

I also forgot to mention that I put a stethoscope to the motor at each cylinder and at cyl's 1 and 3 the was a definite knock. The valve pushed into the piston enough to flow metal up around the edge of the valve. These two pistons are junk because of it. I am not sure if the replacement head I bought is from a 3.0 or a 3.5. The machine shop used the best parts from both heads to make one. It makes me wonder if the valves and springs...etc are fully interchangeable.

Thanks for your info I will make sure not to let it move.

Cheers,

FlyWulf.