Aluminum head experts - opinions please - PeachParts Mercedes-Benz Forum

ah-kay · #1 05-17-2013, 01:25 PM

What can cause the cylinders in the same head to be pitted? This is an aluminum OM603 #14 head. Some cylinders are pitted and some are not. Pictures show 2 good and 2 bad.

Any ideas? What can one do to avoid it?

pimpernell · #2 05-17-2013, 01:56 PM

no expert by any means.............

Edelbrock Performer 5.0 (6037) Heads Pitting Damage

engatwork · #3 05-17-2013, 02:31 PM

I have successfully used MB diesel heads that had a little pitting like that without any issues.

I am of the opinion that it is caused where coolant becomes "stagnant" in areas where it is trapped by the head/block/gasket.

duxthe1 · #4 05-17-2013, 02:46 PM

I believe the OP is referring to the pitting is inside the combustion chamber. It's from water/coolant making its way past the head gasket. You may likely see the same effect at the top of the cylinder bores on the affected cyls.

engatwork · #5 05-17-2013, 02:53 PM

Thanks, I did not look at the pic close enough.

Diesel911 · #6 05-17-2013, 03:02 PM

Since the Head Gasket is not supposed to leak Coolant into the Cylinder the only way to avoid that is to do what is needed to keep the Engine from overheating.

If the Head Gasket leak is due to some design flaw/engineering mistake there is nothing you can do.

In your patricular case the Pits are pretty deep on some near where the Head Gasket Seals. My thought is for that reason alone it should be resurfaced.
You did not say if the Head was checked with a staright edge for warpage. If it has warpage that is another reason to resurface it.

Or you could just use it the way it is and hope for the best.

ah-kay · #7 05-17-2013, 03:15 PM

Quote:

Originally Posted by duxthe1

I believe the OP is referring to the pitting is inside the combustion chamber. It's from water/coolant making its way past the head gasket. You may likely see the same effect at the top of the cylinder bores on the affected cyls.

You are right. I am wondering why the pitting is INSIDE the combustion chamber. I always have a slow coolant leak on this engine. The pitting is quite bad round the top rim area where the head mates to the cylinder. Anyway to patch it easily on a budget?

Air&Road · #8 05-17-2013, 03:30 PM

Make sure that it is pressure tested before installation. Lack of coolant maintenance can lead to thin spots between combustion chamber and water jacket.

Diesel911 · #9 05-17-2013, 04:41 PM

Quote:

Originally Posted by ah-kay

You are right. I am wondering why the pitting is INSIDE the combustion chamber. I always have a slow coolant leak on this engine. The pitting is quite bad round the top rim area where the head mates to the cylinder. Anyway to patch it easily on a budget?

Several years ago Hunter posted a pic of a pic of a 616 or 617 that had a similar Coolant leakage into the Cylinders and the damage was worse and included the top of the Piston.

For sure you need to find out if it is warped too much. If that is the case there is a good chance of it not sealing with the New Head Gasket. After you find that out You will decide what to do.

I can't tell if any of those pits go into the sealing area on the Head Gasket or not. If not as I said you could re-use that Head as is and hope for the best. (My best guess is you can get away with reusing it if not warped.)
If on down the road it fails agin you will just have to fix it the right way or find another Cylinder Head.

ah-kay · #10 05-17-2013, 05:32 PM

Thanks for the answers. The engine was running at 75mph on the freeway when the oil pump chain snapped. A number of rod bearings were spun due to lack of oil. I am in the process of slowly fixing it. The pitting in general is acceptable but there is one place which is too close for comfort to the cylinder rim. I am doing some research as to how to fix it. Any ideas is welcome.

I probably would just put it back together and hope for the best.

Diesel911 · #11 05-17-2013, 08:34 PM

I don't know of any sort of "Filler" you could use to fill in the pits in that area except the below.

There is this stuff called smething like Allumaloy that Harbor Freight sells for repairing Aluminum. It is not specifically a Harbor Freight Product so other places sell it.

If you go to the Harbor Freight site the melting point is in the Ad or in the pdf Instructions. I t meltes at aout think it was around 700 degrees F.

I bought some for a specific job but never used it so I cannot comment on how well it works.

The closest thing I have done to that was I had a Iron head on My van that had some spots were the Coolant had eaten over the top of the Gasket (V6).

I have a Lapping Plate and put various grits of abrasive paper under it and kept at ever so often over the course of 2 Months. I did that to both Heads. I also have a precision staright edge to chech stuff.

One of them still had 2 areas that I though might leak.
So I used some low temp Silver Solder to fill in the low spot. But, it was a micro spot compared to what you have.

so the Allumiloy stuff is not really made for this sort of repair but it depends on how much you like experiment with stuff and adventurous you are.

Another thing I did once is the Head Gasket that came with a Gasket Kit for an inline Gasoline Engine was merely a piece of stamped Steel with ridges in the area it was supposed to seal on. I could not believe that it was going to seal off the Water Passages so I bought a can of Copper Kote Spray and sprayed the entire Head Gasket with 3 layers of that stuff letting it dry between sprayings and used it. It worked.

I have never done that on a Diesel Engine so I can't comment if it would work or not.

gozapper · #12 05-19-2013, 04:28 PM

You might consider taking it to a shop that specializes in head repair and see what they recommend.

I don't mean a machine shop. There are some shops that do block and head repair.

Tom

vstech · #13 05-20-2013, 09:14 AM

it will never seal, and if it's a #14 forget it, no way to resurface... start shopping the yards for a better one.