OM617 Cracked Head....ouch - PeachParts Mercedes-Benz Forum

acb70 · #1 02-22-2016, 09:35 AM

1984 300D Turbodiesel USA Spec-In the middle of the head gasket, cleaning and checking and find this. Ouch! I want to fix it because engine is in alright shape and I really like this car, but I need a replacement head!!

Please let me know if you have one you would like to sell I need to get this car on the road!

Located near Wichita KS

Mike D · #2 02-22-2016, 09:42 AM

Common problem and well documented on this site (Thanks to Will Hunter/Roy!). Lots of used heads out there. Figure on $200-$300 plus any machine work which needs to be done.

Clemson88 · #3 02-22-2016, 10:54 AM

Mercedes OM 617 Cylinder Head | eBay

acb70 · #4 02-22-2016, 11:40 AM

Quote:

Originally Posted by Clemson88

Mercedes OM 617 Cylinder Head | eBay

Ah thanks for the link, pretty far away but I will look into it-

sixto · #5 02-25-2016, 01:03 AM

617 heads are so common and so robust that you might as well replace it but can't it be welded since it's iron?

Sixto
83 300SD

leathermang · #6 02-25-2016, 01:10 AM

Depending on how far to the coolant passage.... it might could be cold patched with overlapping studs.
Lock-N-Stitch Repair for engines, compressors and other cast iron equipment by Reynolds French

ridgerunner · #7 02-25-2016, 09:40 AM

If interested, I have a 83 300d, OM617 turbo engine, that po had dpun a rod bearing, but the head should be good. It's still installed, but I'll be removing it. It's on my hit list; but could be moved up, if there was interest in it.

acb70 · #8 02-25-2016, 11:04 AM

Quote:

Originally Posted by ridgerunner

If interested, I have a 83 300d, OM617 turbo engine, that po had dpun a rod bearing, but the head should be good. It's still installed, but I'll be removing it. It's on my hit list; but could be moved up, if there was interest in it.

Yes I am interested, where are you located?

acb70 · #9 02-25-2016, 11:06 AM

Quote:

Originally Posted by leathermang

Depending on how far to the coolant passage.... it might could be cold patched with overlapping studs.
Lock-N-Stitch Repair for engines, compressors and other cast iron equipment by Reynolds French

Yes I have seen this done before, but for the same price (or less) I could get a good used head that will not be prone to further cracks. The problem with the head I have now is that there are at least 2 other cracks around the prechambers. Darn!

leathermang · #10 02-25-2016, 11:54 AM

Clearly better to find a good head...
I only put that kind of backup info in case someone has a great machine shop they trust.. or a good head is not available.... at a reasonable cost.... a good head in Australia might be impractical ... lol

ridgerunner · #11 02-25-2016, 01:08 PM

Upstate SC.

BillGrissom · #12 02-25-2016, 11:37 PM

Quote:

Originally Posted by sixto

... can't it be welded since it's iron?

Cast iron is different than steel. It is more porous, which leaves embedded contaminants making welding difficult. It also cracks easy from the thermal stress of welding. You have to heat the whole casting to ~600 F, weld, then cool slowly. Not assured to work, and normally only done on very rare parts. For a few short cracks, shops drill the ends to stop the crack and use the "plugging" methods mentioned.

My question is if this crack was benign. If it wasn't losing coolant, getting oil in the coolant, or losing compression, it probably wasn't a problem and might have been thus for >100K miles. Many cast iron heads have cracks that only become a "problem" when people view them.

acb70 · #13 02-26-2016, 09:00 AM

Quote:

Originally Posted by BillGrissom

Cast iron is different than steel. It is more porous, which leaves embedded contaminants making welding difficult. It also cracks easy from the thermal stress of welding. You have to heat the whole casting to ~600 F, weld, then cool slowly. Not assured to work, and normally only done on very rare parts. For a few short cracks, shops drill the ends to stop the crack and use the "plugging" methods mentioned.

My question is if this crack was benign. If it wasn't losing coolant, getting oil in the coolant, or losing compression, it probably wasn't a problem and might have been thus for >100K miles. Many cast iron heads have cracks that only become a "problem" when people view them.

This crack was not benign, the car was overheating at highway speeds, and drinking coolant. A crack that extends to the outside of the combustion chamber will cause problems. The weird thing was this car was only doing that on warm days and after a long drive, just driving to the store was fine, except for it was loosing coolant and the coolant kept turning brown.

vstech · #14 02-26-2016, 10:10 AM

Quote:

Originally Posted by sixto

617 heads are so common and so robust that you might as well replace it but can't it be welded since it's iron?

Sixto
83 300SD

as mentioned, cast iron is ridiculous to weld... brass brazing works well, as you don't have to heat the iron as hot, but pinning the ends of the crack are needed.

back in the 80's I ran some drag engines with multithousand dollar heads and had them welded frequently when they burned from a bad run... amazing to watch. they build a kiln around the head, bring the entire head up to cherry red temp, perform the weld, and then he slowly reduces the heat over the course of a 24 hour day... yeah... it's pricey. and it's SLOW...

leathermang · #15 02-26-2016, 01:22 PM

Vstech, Usually one needs a huge precision jig to clamp to that head during the entire process to keep the surface flat during all that heating and welding and cooling... but for a race engine where you are not having to count on it to drive home those kinds of processes are great.... can save thousands of dollars if done correctly.