77 450 SEL blown head gaskets

[zooklm]

I have removed both of the heads (both blown) due to slow coolant leak that was not addressed properly. My question to the forum is regarding getting the heads checked out. Any one have good experinces with machine shops in the Cocoa/Melbourne area of Florida?

Are the aluminum heads prone to warping and should I get them planed? I also discovered the problems of using non MB coolant as some corrosion has occured on the head where the coolant from the block dead ends against a flat region of the head.

Thanks,
Lee

Originally Posted by zooklm

I also discovered the problems of using non MB coolant as some corrosion has occured on the head where the coolant from the block dead ends against a flat region of the head.

Thanks,
Lee

the corrosion isn't particularly related to non mb coolant, just not flushing the coolant as recommended. however i do highly recommend that you use mercedes coolant.

[kbflorida]

[QUOTE=zooklm My question to the forum is regarding getting the heads checked out."

Check out the Metric Motors web site. They've done MB heads & engines for something like 20 years, and their head services is pretty reasonable.
Do a Google under Metric Motors + Mercedes
They are West Coast, I think, but you really want someone who knows MBs.
I spoke to them last week and it sounds like they're set up to do these jobs right away, and get the heads right back. Like 10 days total or so.

[300SDog]

Most common mistake is shaving/planing alloy heads beyond spec.... bumping compression beyond tolerances - thus ultimately destroying rods, wrist pins, and bottom end.

And machinist planing machines are set to tolerances at inches... This really sucks because the machine itself caint be set low enough to respect MB specs.

About the worst thing i've ever seen was machinist walking away from cyl head planing to have a cigarette while the head got shaved to smitherines.

Pulling the heads yerself is excellent. Now you can shop the heads, along with valve guides and seals, to find machinist for putting the package together.

Machinists tend to be solitary lot, like hermits who burry themselves in their work. Many machinists hate dealing with human beings entirely. But gotta beg, beg, beg em to understand you do NOT want metal removed from the heads!!

Hell, ask em to run a straight edge across the heads to determine if they need planing when you bring it in. Then implore them NOT to shave or chop em.

Humility and respect pays off when dealing with hermit machinists, yet they will respect you for pulling the heads yourself.

Search the MB Rapair Shop Forum here for recommended craftsmen in Florida.

[Tomguy]

DIRECTLY from the MB Lit on cylinder heads:

"Face cylinder head parting surface only in the event of porous or damaged spots. A slightly warped parting surface will adapt itself again when cylinder head is tightened."

Unless the heads are visibly, extremely warped, don't worry about it. As long as you follow the tightening pattern when reattatching the heads, you'll be fine. If they ARE warped, get new (different, used and not warped) ones.

[zooklm]

Thanks for the info. I need to find a precision machined straight edge to check the flatness. I think that I still need to take the heads to someone to get a good cleaning and check the valve guides. The valves look pretty good (not sure about the seats) so they might be able to get by with a relaping.
Lee

[300SDog]

Just one word on valves..... SODIUM-FILLED

Ye caint reseat sodium filled self-rotating valves, but verrry gentle lapping probably wont hurt. Gorrilla tactics of removing metal will cause em to scorch in less than 50k miles. Use the "sodium filled" buzzword when you speak with machinist.

Tomguy, what says you on checking valve guides? Gotta be some precision method for determining excessive play, but i dont know what it is - aside from the obvious wiggle test.