Head Gasket replacement in 617.952 - PeachParts Mercedes-Benz Forum

raymason · #1 02-20-2007, 11:27 PM

My head gasket was leaking exhaust into my coolant so I am replacing it. I measured the warp in the head and it is about .09" . What is the max tolerance for warp and if I need the head ground can it be done with the valve and pre combustion chamber in? My head bolts are all over the max length by .13 to 1.22 mm and was wondering how important this really is to replace them. Any advice would be appreciated

#2 02-21-2007, 06:50 AM

Do you REALLY mean .09"?!?! That thing is a snake if it has that much warp. If you only mean .009 then it can be straightened by a COMPETENT machinist that will cut ONLY enough to make it straight. If it really is .09, look for another head. If you do resort to another head make SURE that you use the correct series and the correct prechambers for your piston type.

Yes you REALLY DO need to replace the head bolts. They are usually good for at least ONE reuse and usually two. Since the head bolts are this stretchd AND you have a warped 617 iron head, I expect that someone has been in there ahead of you and did not get it together correctly. The 617's just don't warp heads very much. You can overheat them like crazy and it won't hurt them in that way. Overheating will cause other problems, but rarely that on this particular engine.

I expect that you can find a head without too much trouble by just posting in the parts section of this forum.

Make sure that you understand the head torquing procedure before going back together with it.

Good luck,

raymason · #3 02-22-2007, 12:28 AM

LOL ya .009" . Thanks for the info I will be phoning around to see who can grind it. Still would like to know if the precombustion chambers have to come off?

Hit Man X · #4 02-22-2007, 12:36 AM

Yeah you'd want to take the entire head apart.

Replace the bolts, they're cheap as can be.

#5 02-22-2007, 06:49 AM

Sorry I missed the question, yes the prechambers must come out if the head is to be milled. As the previous poster said, it really should be completely stripped for surfacing. This shouldn't be a problem, because you will want to do a valve job with new guides while you have it off.

raymason · #6 05-18-2007, 12:49 AM

So I finally sent my head in to be surfaced and was told it had cracks. I found a used one and had it sent direct to the shop and had it done. When I got them both back I could see the head weren't exacltly the same. The glow plugs on the one I bought was the old 18mm loop style and my original one are the 12mm pencel style. The pre chambers are also different. The head was supposed to be off the same type engine 617.952 so did mercedes changes heads at some point and will this replacment head work?

rs899 · #7 05-18-2007, 06:46 AM

That head must be off a NA engine. As far as I know, all turbo engines got the pencil type glow plugs. Even the early 617.950 like I have on my W116 300SD.

It may still work, though- not sure of any other major differences. Probably the prechambers are of a different design than what you had.

Rick

vstech · #8 05-18-2007, 08:23 AM

they also hardened the valve seats on the Turbo heads.
it MAY be ok, but more informed Techs will have to chime in.
John

rs899 · #9 05-18-2007, 08:32 AM

Yeah- you would want to use your old valves and cam, for sure. The later cam is harder and possibly the valves were upgraded for the turbo.

Rick

vstech · #10 05-18-2007, 09:22 AM

OOOH, yes The exhaust valves themselves are Sodium filled to dissipate the heat of the turbo. if your head rebuilder did not swap out the valves, GO BACK and get them off the cracked head.
John

Benzcrusher · #11 05-18-2007, 09:30 AM

Turbo exhaust valves are bigger than the NA valves...

Rashakor · #12 05-18-2007, 10:10 AM

I am positively sure that the NA and Turbo head are NOT interchangeable (there have been many discussions here aout that). You need to go back and get a turbo head. The glow plugs are a dead give away. I the exhaust valves are effectively different that is another sign that they give you a cheap replacement head!

raymason · #13 05-18-2007, 11:10 AM

So I checked the part # on the head and they are both the same 617 016 0301 but the replacment is stamped 77 and my original is a 84. Did mercedes make a turbo in 77?. The valves are the same size but the top of them are different, the one from the 77 head has a big indent on the top and the 84 are almost flat. I am not sure what to do, I don't want to waste time and money putting in something that won't work.

Ray