603.960 engine rebuilding advice - PeachParts Mercedes-Benz Forum

SnoozeKontrol · #1 03-12-2009, 05:29 PM

Hi everyone, bit of a newbie here

I have an 87 300D that overheated on the freeway and seemed to sieze. The temperature gauge was past the top of the scale, oil was running from the bottom of the engine and the engine was smoking profusely. I presumed the engine was toast so I towed the car home where it sat for 3½ years. Lately I enrolled in an engine rebuilding class at my local community college and got the engine to run so my instructor could advise me what to do. It idled ok but there was a loud knocking happening after about 1500 rpm. Considering the history my instructor advised me to take the engine apart and see what was going on. Now everything is apart and strangely it looks beautiful in there. Although there were was one small piece of flattened, twisted metal in the bottom of the oil pan, which I haven't yet been able to identify, all the crank and rod bearings look almost brand new, as do the camshaft bearings and lobes. The cylinder walls are pretty smooth and the pistons and rings look fine. The car has over 360k on it so I'm assuming the engine may have been rebuilt by a previous owner. It has a # 16 head I think - the number is 603 016 14.

So, I have hot tanked the block and now am ready to take the valves out and clean the head in the parts washer. I took the injectors out already but am wondering if I should bother with the prechambers, since I would apparently have to buy an expensive tool to remove those. My instructor knows a lot about gasoline engines but not so much about diesels so I'm just trying to get the best advice. I looked around for a 603 engine rebuild thread but didn't find one. Prior to this little excercise, the most complicated work I have done is changing my pads and rotors, so if anyone has some tricks or advice on what to look for it would be much appreciated.

Thanks

Chris

Brian Carlton · #2 03-12-2009, 05:49 PM

The first and most important thing to do is to send the head to a highly qualified shop for evaluation and pressure check. The chances that the head is not cracked after such an escapade are just about nil.

These people have the required expertise:

www.mercedesengines.net

dieseldiehard · #3 03-12-2009, 06:42 PM

Quote:

Originally Posted by SnoozeKontrol

Hi everyone, bit of a newbie here
The car has over 360k on it so I'm assuming the engine may have been rebuilt by a previous owner. It has a # 16 head I think - the number is 603 016 14.
Thanks
Chris

That is a series #14 head. The 603-016 is the part designation for a head itself, the serial is the next two digits.
see this thread: http://www.peachparts.com/shopforum/showpost.php?p=1901383&postcount=17

Look at the timing ramp on the IP also, it has to be smooth with no galling or that too will need to be replaced. I would agree that with that number of miles and the rings aren't worn thin then it was definitely rebuilt at some time.
Also agree that the head needs to be pressure checked and skim cut to assure flatness if it has no leaks. Do you need a reference to a experienced head shop? I know a good one in Southern Calif. They will also Remove and clean the pre-comb chambers for you at the same time.
DDH

mplafleur · #4 03-12-2009, 09:33 PM

Quote:

Originally Posted by SnoozeKontrol

I looked around for a 603 engine rebuild thread but didn't find one.

Try this one...

http://www.peachparts.com/shopforum/showthread.php?t=242705

SnoozeKontrol · #5 03-16-2009, 06:48 PM

Thanks to Brian C for the machine shop referral (they quoted $60), ddh for the head designation and timing ramp advice (but sorry, what's an IP? The chain guide needs to be replaced for sure), and Mike L for the rebuilding thread (very interesting). Also thanks to diesel911 for the pm.

After cleaning the head no cracks are visible, although I haven't got the prechambers out yet and I'm told that's a critical area to check. My instructor doesn't think it's necessary to get pressure testing since he has come to the conclusion that the knocking noise we heard was probably an exhaust manifold leak rather than an actual knock. Still, I don't want to omit that step as I think the money would be well spent if only for peace of mind, so I'm gonna get it done anyway.

Bio300TDTdriver · #6 03-16-2009, 08:21 PM

Quote:

Originally Posted by SnoozeKontrol

Thanks to Brian C for the machine shop referral (they quoted $60), ddh for the head designation and timing ramp advice (but sorry, what's an IP? The chain guide needs to be replaced for sure), and Mike L for the rebuilding thread (very interesting). Also thanks to diesel911 for the pm.

After cleaning the head no cracks are visible, although I haven't got the prechambers out yet and I'm told that's a critical area to check. My instructor doesn't think it's necessary to get pressure testing since he has come to the conclusion that the knocking noise we heard was probably an exhaust manifold leak rather than an actual knock. Still, I don't want to omit that step as I think the money would be well spent if only for peace of mind, so I'm gonna get it done anyway.

I'll bet your instructor doesn't know how easy it is to crack the 14 01 head on a OM603 engine. Spend the money and have it pressure checked. I'll be amazed if it's not cracked and warped.

IP = injector pump

engatwork · #7 03-16-2009, 08:31 PM

Quote:

knocking noise we heard was probably an exhaust manifold leak rather than an actual knock.

what? Has he had his hearing checked?

babymog · #8 03-16-2009, 10:16 PM

The head is critical as all have said.

There are some photos floating around this forum somewhere of a 14 head that didn't have visible cracks, until the valves were removed. Cracks above the valves and around the valve seats.

I had one #14 head that had visible lines/cracks between the pre-chamber and the valve, but passed a pressure test.

Warping is also a problem, you can only remove so much material to straighten it out, and there is a concern that overheating the head will anneal/soften the aluminum so that the bolt seats will no longer be able to maintain the correct pressure from bolt torque to keep a head-gasket sealed. The FSM specifies that the hardness of the head should be tested!!

Diesel911 · #9 03-17-2009, 02:16 AM

I am not sure of the spelling but if the head is Aluminum ask you instructor if their shop has a Dye Penatrant Tester; to test for cracks.

Oracle12345 · #10 03-17-2009, 10:26 AM

Just to save you some headaches down the road, someone who doesnt have or little experience rebuilding heads and engines shouldnt be rebuilding mercedes engines since they arent as simple as a chevy V8.

Diesel911 · #11 03-17-2009, 03:55 PM

Quote:

Originally Posted by Oracle12345

Just to save you some headaches down the road, someone who doesnt have or little experience rebuilding heads and engines shouldnt be rebuilding mercedes engines since they arent as simple as a chevy V8.

While the advice that everyone has given is good advice; remember he is doing this to learn new skills. Reguardless of the result of the rebuild he is going to learn.

dieseldiehard · #12 03-17-2009, 04:14 PM

yes. Learn he will. Oh yes, first lesson: IP is an Injection Pump.

Oracle12345 · #13 03-17-2009, 10:05 PM

Quote:

Originally Posted by Diesel911

While the advice that everyone has given is good advice; remember he is doing this to learn new skills. Reguardless of the result of the rebuild he is going to learn.

true and it will be expensive education to say the least. So I say good luck

a2t · #14 03-17-2009, 10:12 PM

Quote:

Originally Posted by dieseldiehard

yes. Learn he will. Oh yes, first lesson: IP is an Injection Pump.

reminds me of a time in mechanical engineering school in vibrations class...3/4 way thru semester, 45 min into a class of instructor talking about e^(x...), e^(y-...), the 4 whole chalk boards covered in formulas with e in it. So my hung over buddy sittin next to me raises his hand and asks "whats e ?"

there are no stupid questions...

Id get the head checked...if you really pegged the temp gage its toast.

babymog · #15 03-17-2009, 10:40 PM

Also, get the FSM (Factory Service Manual) and read the many (not connected) areas involving head work and other areas that you're servicing. There are specifications and procedures that don't exist in normal engine rebuilds and are necessary (such as the hardness test).