Author Topic: Doing 6.9 head gaskets soon, please offer advice/tips/etc  (Read 6819 times)

daantjie

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Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
« Reply #30 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
Daniel
1977 450 SEL 6.9 - Astralsilber

3l33ter

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Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
« Reply #31 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!
'75 280S
'77 6.9
'82 300TD

rumb

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Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
« Reply #32 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?
'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550

3l33ter

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Re: Doing 6.9 head gaskets soon, please offer advice/tips/etc
« Reply #33 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.
'75 280S
'77 6.9
'82 300TD