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Head gasket change questions M117
Ok, i'm finally going to get around to changing my m117's head gaskets.
Couple of questions really.. What should I order? Definately: Head gasket sets, Intake boot thing, New fluids, Maybe: Head bolts? Valve stem seals? All other engine related maintinance is up to date, ie chain, guides and cam oiler plastics. My engine doesnt produce blue smoke, so i'm not sure if I should do the valve stem seals. When I had my parts car, I tried taking off the intake manifold, but the allen headed bolts refused to budge and rounded, any tips on avoiding this again? Finally, what do I do with regards to the chain before taking the head off? Ben
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Ben '85 500 SEL '85 928S2 '88 560 SEC '90 750i |
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I wouldn't spend that much time & not have a valve job & guide replacement done! ALL of the idle balance rubber hoses to the injector insulators & anything rubber & plastic should be replaced.
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MERCEDES Benz Master Guild Technician (6 TIMES) ASE Master Technician Mercedes Benz Star Technician (2 times) 44 years foreign automotive repair 27 Years M.B. Shop foreman (dealer) MB technical information Specialist (15 years) 190E 2.3 16V ITS SCCA race car (sold) 1986 190E 2.3 16V 2.5 (sold) Retired Moderator |
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What would a machine shop charge for a valve job and a head resurface?
This car is my daily beater, so I dont want to go over the top with it. It runs great apart from it using water. Do I zip tie the chain to the cam sprocket and remove the sprocket from the camshaft?
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Ben '85 500 SEL '85 928S2 '88 560 SEC '90 750i |
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Expect to pay 250-350 a head for machining. I agree, to have the heads off and Not so the guides is a false economy.
There are also 8 large seal rings on the intake plenum. Plan on doing those as well as what was mentioned above. I'd also pick up some industrial grade paint stripper..it will do a good job cleaning out the intake manifolds of all the built up carbon. I'd also block off the air injection passages while you are @ it. they have a habbit of clogging/making a mess over time so I typically block them off and remove the air pump. Jonathan
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Blue Ridge Mercedes Jonathan Hodgman http://www.blueridgemb.com/ Enthusiast Service, Restoration & Tuning. Follow Us on Facebook! Located in the Atlanta area Specializing in all pre and post merger AMG's including Hammers and DOHC M117 engines. Mercedes Repair Atlanta |
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Around this area $500-$600 for valves & guides.
Spending 20 hrs & not at least having them inspected would be a big waste of time!
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MERCEDES Benz Master Guild Technician (6 TIMES) ASE Master Technician Mercedes Benz Star Technician (2 times) 44 years foreign automotive repair 27 Years M.B. Shop foreman (dealer) MB technical information Specialist (15 years) 190E 2.3 16V ITS SCCA race car (sold) 1986 190E 2.3 16V 2.5 (sold) Retired Moderator |
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Well, i'm planning on having the heads resurfaced anyway, so i'll ask them to look at the valves and guides when I take them in.
The whole car only cost me £80 ($150 or so) and i've been using it for 2 years, so it doesn't owe me anything. One one hand, i'd just like it up an running on the cheap, but the engineer in me wants it all done right. Edit: Should have said, the car is a euro, so doesnt have air injection.
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Ben '85 500 SEL '85 928S2 '88 560 SEC '90 750i |
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How about new exhaust manifold nuts? I believe they use deformed copper nuts that don't hold so well the second time around. Do you have the offset hex bit that lets you get to the head bolts blocked by the cam? http://www.shoptoolsshoptools.com/shopexd.asp?id=2912 Sixto 93 300SD |
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Are the nuts M8? I have a box of locking copper M8's, otherwise i'd have to order them too. I dont have an allen socket thats like that, but my short (1")allen socket seemed to fit ok when I retorqued the head bolts not too long ago.
So I have to break the chain on each sprocket and wire the ends for a helper to hold onto? Is there a position on the crank where the pistons are all in such a fasion that the camshafts are free to rotate without valve to piston interferance? IIRC on my Porsche V8 its 45'.
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Ben '85 500 SEL '85 928S2 '88 560 SEC '90 750i |
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Don't break the chain, just slip it off the sprocket after you remove the tensioner.
IIRC there is no non-interference position of the cam. Sixto 93 300SD |
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117 top end o/haul
three things have been missed.there are chain rail pins that need to be pulled.requires tool or creative thinking using 6mm bolts and spacers.the aluminium block needs to have the head bolt holes drilled,tapped and heilicoiled.[with steel bolts in alu threads it's not a case of if but when the threads will break]lastly completely o/haul the intake manifold.replace anything with rubber including the large rubber below the fuel distributor plenum.watch out for the allen head bolts in the intake they will strip out very easily.best to have 6 point star socket handy that you can hammer into the bad bolts and then they will come out.
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David S Poole European Performance Dallas, TX 4696880422 "Fortune favors the prepared mind" 1987 Mercedes Benz 420SEL 1988 Mercedes Benz 300TE (With new evaporator) 2000 Mercedes Benz C280 http://www.w108.org/gallery/albums/A...1159.thumb.jpg |
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That brings me onto my next question.. What is the thread pitch of the M10 head bolts? I need to order a tap and coil inserts to suit.
I think the cause of my head gasket going was the problem of one of the head bolts stripped out of the head. I found this out when trying the old retorque head bolts trick. I'm also ordering some screw and stud extractors for the intake bolts as a last resort if the torx bit trick doesn't work.
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Ben '85 500 SEL '85 928S2 '88 560 SEC '90 750i |
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You are going to need a special jig for drilling/taping the block. The bolts don't thread in perpendicular to the face of the block. I believe the jig runs about 500$ here in the US.
I know Ashenmacher sells a kit w/ the correct drill bit/tap and MB has the correct heli coils. Jonathan
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Blue Ridge Mercedes Jonathan Hodgman http://www.blueridgemb.com/ Enthusiast Service, Restoration & Tuning. Follow Us on Facebook! Located in the Atlanta area Specializing in all pre and post merger AMG's including Hammers and DOHC M117 engines. Mercedes Repair Atlanta |
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I just called MB to get a price on the jig and special piloted tap. The jig runs at 447GBP so we're looking at about $800. The Ashenmacher jig I have sourced for $377 so about £200 plus shipping and import duty to the UK. This is still alot of money for something i'm only going to use once (well twice).
I'm going to try calling around to some so-called MB specialists locally and see if they have one they'd rent out to me... I'm not optimistic though.... the w116 and w126 is a rarely seen car here, especially with a V8 Is there any trick I can use to not use the jig?
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Ben '85 500 SEL '85 928S2 '88 560 SEC '90 750i |
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I've done the job some 15 times and I wouldn't trust it Not using the jig. If you screw up then your going to be up quite the creek.
Jonathan
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Blue Ridge Mercedes Jonathan Hodgman http://www.blueridgemb.com/ Enthusiast Service, Restoration & Tuning. Follow Us on Facebook! Located in the Atlanta area Specializing in all pre and post merger AMG's including Hammers and DOHC M117 engines. Mercedes Repair Atlanta |
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I called into the Mercedes specialists, and they have never done the job. They said that they would use the machine shop in our next town. They do most of the machine work for the local garages around here and have a good reputation. They said that the machine shop would come out to drill and helicoil the block in situ. Whats anybodys views on this?
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Ben '85 500 SEL '85 928S2 '88 560 SEC '90 750i |
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