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Garage => Mechanicals => Topic started by: 3l33ter on 13 June 2014, 08:13 AM

Title: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 13 June 2014, 08:13 AM
I got my 6.9 almost a year ago, but I haven't had a chance to touch it since then. It's been in my driveway while I've been finishing other projects.

It needs head gaskets so I'm planning to do that next week. I already have the new gaskets from MB. My plan is to take the heads to my machinist to be checked, and any necessary work done. Some relevant info: It has 160k miles, ran well when parked, except for the slight mixing of coolant and oil, and it needs a smog check as soon as it's running again.

Is there anything special to watch out for when doing this job? Do I need to buy any special tools? Any while-I'm-in-there things to do?

Thanks in advance!

Hopefully when it's running I can make a proper introduction thread.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: oversize on 13 June 2014, 04:11 PM
Consider all the other gaskets you'll need as well. Lots of the rubber hoses and connectors will be brittle and will probably break on removal.
Check the timing chain for stretch and the cam sprockets and rails for wear.
It's quite common for some of the inlet manifold bolts to break as they enter the cooling system and corrode. Valve guides and stem steals will probably need to be reconditioned or replaced.  You may need the headbolt tool so you can torque the bolts down around the cam towers. Personally I'd pull the engine to do this job but in situ you may find you have to remove the brake booster to get clearance for removal...
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: oversize on 13 June 2014, 04:17 PM
Oh and you'll need cam oiler connectors and exhaust manifold nuts. Consider resealing the water pump and replacing the front crankshaft seal
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 18 June 2014, 01:48 PM
Thanks for the info!

What's the head bolt tool? A special socket?

What's a cam oiler connector?

I think I'd rather remove the brake booster than pull the engine, I'll go that route first.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: CraigS on 18 June 2014, 06:48 PM
It's a pig of a job - especially on a right hand drive. To get the booster out, it is easier to remove the instrument cluster to get at the top nut. The other 3 are OK. You should also change the steering coupling while the exhaust manifolds are off. Get a VRS kit for the engine. This however will not include the injector seals. The special tool for the head bolts is a hook tool that goes around the cam and is all but impossible to do without. As mentioned, there is a strong possibility of breaking some of the studs that hold the intake manifold on - front left and 2 front right. Change the engine mounts at the same time and check the small dampers. Change the timing chain and make sure the chain adjustor is working properly. Replace the rubber boot that attaches the throttle body to the intake manifold and replace the two special clamps.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 20 June 2014, 12:23 PM
Is this the tool you're talking about?

http://www.pelicanparts.com/catalog/shopcart/TOOL/POR_TOOL_MERCED_pg14.htm

I think I can make one of those. Gotta go buy a sacrificial allen wrench and some bar stock. :)

I'll wait until I'm in there, so I can measure dimensions and clearances.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: CraigS on 21 June 2014, 02:47 PM
That's the one.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: rob280sel on 22 June 2014, 04:35 PM
While the heads are off take them to a head re-conditioner to check warp/porosity/hardness/cracks and how the valves,guides and seats are going.
Because why did the head gasket go in the first place?
No use putting the heads back on and find you have to do it all again.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 17 November 2014, 05:34 PM
OK, it's been a while, but I finally got around to putting some more time into the 6.9. I got a valve cover off and I see why I'd need the curved allen tool for the head bolts.

But, what if I just take the camshaft off first? I need to take that off anyway, so actually I don't see the need for the special tool at all...
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: marku on 18 November 2014, 10:08 AM
You can do it without the special tool and there really is no point in making one or at least how I tried to make it. Welded an allen key which when used actually twisted it in to a spiral. Use a key in a socket tap it firmly in first and then fit the bar extension it just works. You can take the cam off first but you will need to torque them all down when re-fitted. Machined the heads, reseated valves (MB say take the same of the seats as the head) and replaced guides and seals. Be wary of exhaust manifold studs they break really easily. Head kits come with all gaskets but not water pump. Doing the 450 in place was hard enough so don't envy you with the 6.9. Good luck.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: TJ 450 on 19 November 2014, 07:06 AM
The special tool is for the M117... I don't think anything is required for the M100. Cam oiler fittings are not present on this engine either... it's rock solid with no plastic fittings.

You can't buy a new water pump, or at least it's $$$$, so a recon is really the only feasible option... they're listed on eBay. Count on breaking a few bolts, as they invariably do.

Tim
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: koan on 20 November 2014, 02:44 AM
This is a big job that will take some time to do properly.

If you get the valves and guides done which is worth doing given the amount of work involved to do head gaskets you are going to need a spring compressor and go/no-go gauge to readjust the valve "clearances".

Have a look through koan gallery (http://gallery.w116.org/v/garage/koan/), in "Tools" you'll see my DIY bent allen key done with heat, and my DIY spring compressor design. Also under "Engine work" there's a few pictures taken during the job.

Also in my gallery in "Misc" on the second page is "M100_head_bolt_caution" which is about the spacer on front head bolt of LHS head.

One problem I encountered was getting the inlet manifold off, the EGR pipe gets stuck under the cylinder head overhang, it's a pain.

I seem to remember having to undo engine mounts and jack the engine up to get exhaust manifolds off.

As I said it's a big job and there's lots of other things that may be worth replacing along the way, timing chain, chain guides, tensioner rail, previously mentioned crank seal... it goes on and on...

Good luck.

Ken
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 24 November 2014, 05:06 PM
Did you have to take off the brake booster to get the driver side head off?

I was doing great not breaking any bolts until the front left bolt on the upper intake. That sucker is seized badly. I drilled the head off, and I can't pull the intake off. Next, I will drill a pilot hole into the bolt shank and try a bolt extractor.

I still need to pull the exhaust manifolds, entire intake, cams/chain, and then the heads go to my machinist.

I was quoted about $500 for all the valve guides from my local dealer. Does that sound right? Also, I bought the head gaskets from them for $150 each after begging for a discount, but that's just the head gaskets alone.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: koan on 24 November 2014, 10:45 PM
Did you have to take off the brake booster to get the driver side head off?

On RHD you do.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: CraigS on 25 November 2014, 02:15 PM


I was doing great not breaking any bolts until the front left bolt on the upper intake. That sucker is seized badly. I drilled the head off, and I can't pull the intake off. Next, I will drill a pilot hole into the bolt shank and try a bolt extractor.



Unless you have the bolts off both sides, you will never get it off. They are angled at about 45 degrees to each other so you are pulling against the tension on the opposite side. If you can get one of the two out, you have a chance. It is very easy to damage either the intake or the head if you get it wrong. Might be better to get someone to drill out the broken studs before trying to remove the intake.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 27 November 2014, 01:03 AM
There is only 1 bolt remaining for the upper intake. I can get the intake to wiggle, but it won't come up off of the headless bolt.

Hopefully this weekend I'll get a chance to go back to it and extract that demon bolt.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 08 December 2014, 01:26 AM
I tried a bolt extractor, and the tip just broke off. Yikes, that had me seriously worried. But I managed to pry the intake up off of the bolt with lots of wiggling and some penetrating oil. The corrosion around that bolt was so bad, it was holding the intake firmly.

Then I spent 2 sessions of about 3 hours trying to figure out how the hell to lift the intake out. It just didn't want to come off. Finally I realized that the EGR pipe was getting hooked under a protrusion of the driver side head. I had to unbolt a small clamp which anchors the EGR pipe to the rear of the intake manifold, which helped very little, but enough for me to tug the pipe around the obstacle. Then I removed the driver side valve cover, to give the EGR pipe more room. And after a whole lot of wrestling, the intake finally came off.

I still have to deal with the broken bolt. With the intake off, I cut off about a centimeter of the bolt so that the screw extractor remnant is no longer there. I think I'll try welding on a nut next.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: marku on 09 December 2014, 10:29 AM
Welding a nut or another bolt to it if it is too near usually works as the heat frees it up. I broke off an extractor in a stud that had sheared off in the head. Took it to a friendly workshop who said that the broken extractor couldn't be welded but they knew someone who had a spark eroder. This took out the tip of the extractor allowing a bolt to be welded to the stub which they did even though it was inside the head.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 12 December 2014, 05:14 PM
I want to take off the brake booster now. I can't find the relevant information in the workshop manual PDFs. I have the haynes and chilton books for the w116 at home, but if anyone has any tips, I'm all ears! :)

I'm also going to paint it while it's out. I've heard a w126 booster can be used - is it an upgrade? Should I get one?
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: TJ 450 on 13 December 2014, 09:15 PM
Four nuts on the inside, and the one bolt where the brake pedal attaches. You can leave the master cylinder attached, and it is a very tight fit in there... a bit of brute force is needed to jam it up past the strut tower.

There is also supposed to be a seal where it attaches to the firewall.

Tim
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 02 January 2015, 02:49 AM
The driver side head can be removed without removing the brake booster, and without jacking the engine to tip it over. The only bolt which poses a problem is the rear top corner one, or #18 in the WSM (the larger one holding the rearmost cam bearing tower).

All you need to do is use a short 10mm allen socket to unscrew the bolt, pull it out a couple of inches, and use tape or something to hold it from falling back in (I used a small magnet). Then undo the cam oil tube, and remove the camshaft including all bearing towers except for the rear one which can't come off. Now simply remove the head with the rear cam bearing tower and single bolt.

*Don't forget to put that rear bearing tower and long bolt back in BEFORE mounting the head!

Honestly, the SLS was more of a problem for me. The brake booster was basically a non-issue.

Now, I have to get these heads ready for the machinist, and strip down all the parts that are to be cleaned in the solvent tank.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 02 January 2015, 02:53 AM
I also want to note that the special tool for the head bolts is necessary after all. The job can't be done without it (well, maybe disassembly). I'm going to make one myself - I'm good at fabbing and I usually make my own special tools.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: oversize on 03 January 2015, 03:19 AM
I still think it's easier to pull the whole engine....
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 07 January 2015, 03:07 AM
Well, now that the heads are off, looking back, it wasn't that bad of a job. Even with the nightmare of figuring out the EGR pipe, I'm glad I didn't take the whole engine out.

I got the broken bolt out by welding on a nut. I also had 1 broken exhaust stud which came out easily with an extractor.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 07 January 2015, 10:51 PM
I don't know where to get a parts catalog for Mercedes. I had to make a trip to the dealer, but the parts guy was super helpful. I got a list of all the parts we thought I'd need for this job. I wanted to list them here in case it ever helps anyone.

100 016 28 20 - head gasket
100 016 29 20   - head gasket
000 997 05 98   - chain link
000 997 79 94   - roller chain
100 052 01 16   - slide rail
100 052 02 16   - slide rail
115 052 07 16   - slide rail
116 050 27 16   - sliding rail
100 050 01 15   - tension lever
100 050 05 11   - chain tightener
115 050 00 67   - valve stem seal kit (kit of 8 )
100 050 49 24   - valve guide intake
100 050 56 24   - valve guide exhaust
100 016 12 21   - valve cover gasket
100 016 11 21   - valve cover gasket
100 140 04 65   - intake manifold connector (upper to lower)
100 141 16 80   - manifold gasket
100 141 17 80   - manifold gasket
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 13 January 2015, 07:03 PM
My machinist says one of my exhaust valves is cracked. Yikes!

So I'll make a stop at the dealer tomorrow to see if they can even get one for me, and how much it would cost. But if anyone has any leads I'd appreciate it.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: oversize on 14 January 2015, 05:14 AM
Better to find that out now and have it fixed than the alternatives!
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: TJ 450 on 14 January 2015, 10:05 AM
Your best bet is to contact the Classic Center for the parts if you must go genuine.

Tim
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: ptashek on 14 January 2015, 12:01 PM
I don't know where to get a parts catalog for Mercedes.

If you're willing to pay a, relatively small, yearly subscription: http://service-parts.mercedes-benz.com/ (it's a legit Mercedes service)
In Europe it's 20EUR/year + tax. Well worth it if you're planning to buy a good deal of parts.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 10 March 2015, 12:02 AM
OK, I can't believe 2 months have gone by, but now I have some time to resume this project. I bought a genuine NOS valve, and 16 aftermarket valve guides from SI Valves. The heads are at a shop getting welded, then they'll go back to my machinist to get worked on.

In the mean time, I'd better clean the block surface. I also need to order the parts for the chain job. Wallet, brace yourself!
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: daantjie on 07 December 2015, 07:12 PM
Any update on this endeavour..?  I am eyeing this job myself, but the long breaks in posting here makes me worried, he-he-he ;D
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 07 March 2019, 01:18 AM
I can't believe it's been 3+ years, but I'm finally working on this car again. In October 2015 my father passed away and since then my life has just been a hectic storm of work, family, and more work. The 6.9 just sat and sat, and although the cost of storing it is not low, it was indoors and in the back of my storage unit, so "out of sight / out of mind" as they say.

I have a friend whom I met at the indy shop where I worked in my university days. He's a Mercedes nut and he recently moved to my area, and being the glorious, generous dude that he is, he decided to help me get the 6.9 job rolling again. Over the last 3 weekends we got the car uncovered from all of the boxes and random crap it had accumulated, and got it lifted up. We cleaned the engine block, replaced the one timing chain tensioner I hadn't done yet, and started cleaning the piston tops. Then I painted the cylinder heads, which have been sitting in bags since they came back from the machine shop. I painted them with POR-15 engine enamel in silver.

Today we hit a big milestone. I'll post about it when I have more energy, but it's been a long day. I'm really excited to be working on this car again and can't wait to actually drive it again!
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: rumb on 07 March 2019, 07:35 AM
1st step is find both head gaskets, I believe one is NLA now. I can loan you my valve lash checking tool.

Are you doing with engine in car or out?   I think out is easier in long run. You may encounter broken bolts that require  good access to work on as well as access to entire front of engine. On my spare engine I broke several intake manifold bolts.

beware of mission creep! If engine out, detail engine bay, replate all yellow zinc parts?
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 09 March 2019, 12:29 AM
Engine in.

I have already acquired head gaskets, about 4 years ago, and was told by the parts counter guy that they were the last ones (or maybe I'm remembering incorrectly and only one of them was the last one). Lucky me... I better not bugger it up. On a side note, I was strongly considering having Cometic make me some MLS gaskets (which would mean they'd have the patterns to make more for people).

I did have 1 or 2 broken intake manifold studs, but they've already been removed via welding on a nut. I need to remember to put all of the exhaust manifold studs that backed out back into place BEFORE bolting on the heads.

On Wednesday we got all of the cleaning done to the block surfaces. We removed the dowel pins by tapping the inside with an SAE 3/8 tap (perfect size) and using a bolt, nut, and washers as a press. We removed the SLS drive gear, and we safely tucked the timing chain into the block so it wouldn't fall down all the way. We did all of this to unobstruct the head gasket surfaces of the head. The old gasket material was so incredibly stubborn to remove, but eventually we got it clean. Right now it is coated with oil (to stop rust).

Next time we will use a granite surfacing block with wet-or-dry emery paper to make the block totally flat. I think I will blueprint the block first.
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 22 May 2019, 09:18 PM
We have been making slow and steady progress on any evenings that we had free time. Tonight we actually got the heads mounted!

More details on that later... but for now, we've hit a snag. On the driver side head, the head bolt furthest forward and furthest towards the outside just won't thread in all the way. We checked and there are only 3 lengths of bolt - longest are for the cam towers, medium are for the intake side, and the short are for the exhaust side. This one hole just doesn't seem deep enough. We probed the hole with a screwdriver and it is physically deeper than the bolt's length, but maybe the threads don't go in far enough. I'm at a loss.

Is there a bracket or something that goes on under this bolt?

EDIT:
Looking through my old photos, it kinda looks like a thick spacer goes underneath this bolt. Can anyone confirm this? I think I saw a spacer in my box of hardware from this engine...
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 23 May 2019, 12:23 AM
I answered my own question, thanks to my friend who happens to have the bloody workshop manual!  ;D
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: daantjie on 23 May 2019, 08:07 AM
Nice work!  If all else fails RTFM ;D
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: TJ 450 on 23 May 2019, 08:23 AM
Yep, that spacer was missing on my car, so I made my own by grinding down an old socket. It’s still on the car now as I was unable to obtain one.

Tim
Title: Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
Post by: 3l33ter on 25 May 2019, 01:43 AM
I found the spacer! :D

I've been busy but when I get a chance I'll update with pics and the current state of the project. I'm SOOO stoked with the progress.