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New forum member attempts 6.9 resurrection

Started by 1960mog, 11 June 2013, 08:28 PM

zedster

1979 450 SEL "Spinne Blaue"

oversize

Welcome to W116 ownership!!!!  Very few will be completely rust free and it's a good thing you found it now before it becomes any worse!  I'd strip the rest of the interior to check for any more (particularly the sunroof frame and firewall).  Fix it all and you'll have a sound car for many years into the future.  The key is to keep them out of the elements....  However it seems a little unusual since your car apparently came from a dry climate.

BTW I'd add some squirts of oil into each cylinder, then turn her over by hand.  Then crank her over with no plugs to build up oil pressure before trying to start it for the first time.  If you aren't already several steps ahead I'd pull the rockers covers and check the timing chain stretch.  Then you can refill with new oil, using about 5L poured over the cam lobes, journals and the chain/sprockets.  I wouldn't use much more as it may not all return to the tank and you don't wanna crank with 12L all in the sump.
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

1960mog

I believe that rainwater entered through the cracks in the window seals and was retained by the foam insulation of the floor over the last 14 years.
The sun roof frame has a lot of rust and I also found some rust on the fire wall, when I changed the hood release cable.

The car has option code 494, it should be a California model and the climate in Utah, where I found it, is even dryer.

I already put oil in the cylinders and I will change the timing chain. This car has 128000 miles on the clock and I don't think the chain was ever changed.
The condition of the chain rails concerns me more.
Did Mercedes already use the hard plastic rails in 1978?
Or do I still have the aluminum rails.
78 6.9 #4084
79 6.9 #6669

oversize

Lots of people blame the windscreen seals and I'm sure it's part of the problem but more likely it's the sunroof, plenum and firewall that are the main cause of the water leaks.

I'm not sure about the rails.

Do you have more pics??
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

1960mog

You probably right about the sun roof.

What is the plenum?
The air inlet below the wind shield?

Here some more pics of the rust after I removed more of the interior and vacuumed it out.











Only after sand blasting will I be able to tell how much of the sheet metal can be reused.


On the bright side.
I cleaned and pained the oil tank.











78 6.9 #4084
79 6.9 #6669

1960mog

It did rain today and I was able to confirm that the window seals are leaking.

A pic that shows the condition of the window seal.





Water drops are hanging on the inside from the window seal.





I can't tell that the seal is the only source of this puddle.





The same happens to the rear.







So far I didn't find any wet spot around the sun roof.

78 6.9 #4084
79 6.9 #6669

adamb

OMG, I've never seen rubber in such an awful state. For all the advantages of dry climates, the damage done to paint and perishable components is astounding. Comparatively, rubber lasts a long time in damp climates like the UK and so does the paint as long as you keep the car clean.

1960mog

Quote from: adamb on 12 July 2013, 03:53 AM
OMG, I've never seen rubber in such an awful state. For all the advantages of dry climates, the damage done to paint and perishable components is astounding. Comparatively, rubber lasts a long time in damp climates like the UK and so does the paint as long as you keep the car clean.

That is the tradeoff for rust free sheet metal.

It is unfortunate that my car has so much rust.
It's not uncommon to find Mercedes of this age, or older, here in the American south west that are rust free.
This is what makes cars from this region so tempting for European buyers.

About once a year I send a 114/115 model to a friend in Germany.
All he asks for is a rust free and accident free body.
Technical condition and the condition of the paint, chrome and interior does not matter.
It's cheaper for him to pay for shipping, duty and tariffs, then to do the rust repair on a German body.
Even if he is very good in his craft, he still ends up with a 'repaired' body, instead of a original, untouched one.
78 6.9 #4084
79 6.9 #6669

1960mog

Looks like there was once a swimming pool in the spare tire well.
The drain hole is still open, maybe it was blocked by the spare tire.







The left side of the trunk looks good, only the right has a rust hole and some bondo on the out side.







My engine already has the hard plastic chain rails, but they are not broken yet.
I am surprised by the good condition of the cams and how clean the engine is inside.









78 6.9 #4084
79 6.9 #6669

oversize

Nice job on the tank!  Yes your engine is very clean inside, which is encouraging.  I wonder if all replacement chain guides are now plastic?

Interesting that your US floors are quite a bit different to ours, obviously to incorporate the exhaust cats.  But what are the raised ridges in the middle of the front floors??

Personally I'd rather no rust than pristine rubbers, but it can all be fixed if you're determined enough
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

1960mog

Quote from: oversize on 12 July 2013, 07:15 PM
Nice job on the tank!  Yes your engine is very clean inside, which is encouraging.  I wonder if all replacement chain guides are now plastic?

Interesting that your US floors are quite a bit different to ours, obviously to incorporate the exhaust cats.  But what are the raised ridges in the middle of the front floors??

Personally I'd rather no rust than pristine rubbers, but it can all be fixed if you're determined enough

I hope that this type of floor is not unique to the 6.9 and that I can get replacement parts.
I am not a friend either of rust either, but I have to buy what I can get, for the money I can spend.

Here is a pic of the rubber seal inside the WUR, or what is left of it.



Here it is with three millimeter O ring cord as a replacement seal.
I hope this will cure the vacuum leak on this unit.

78 6.9 #4084
79 6.9 #6669

TJ 450

That's looking great!

The plastic chain guides in the M100 engine are not known to break. This only applies to M116/7 engines. However, I think it is a good idea to change them if you are replacing the chain. The new ones are also plastic, and the timing chain tensioner rail lining wears too.

The camshaft oiler tubes are also firmly mounted on these, and the only issue one is likely to find there is blockage due to sludge.

Considering your engine is so clean, I don't think you have much to worry about there.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

oversize

I'd track down a good sheet metal fabricator, after checking the cost of new repair panels and compare the prices
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

oversize

Nice job on the WUR!  I'd put a dab of sealant at the ends of the new seal to make sure there's no leaks
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

1960mog

Hi
I didn't do much the last week or two on the car, but I was able to determine that my WUR is beyond a repair kit.
After installing the make shift O ring seal, I hooked it up again to my injection testing set up and got the same PSI readings.
40 PSI after starting the fuel pump, then creeping up to 60 PSI.
The pressure shouldn't move at all as long as the heater or vacuum is not hooked up to the unit.
I stole the WUR of a 380, installed it on my system and at once all the pressures fell in line.
54 PSI max with the heater energized, that is exactly where it should be.
The control pressure decreases with the application of negative pressure, as it should do.
Then I put the WUR in the freezer for about one hour, and installed it as fast as possible.
10 PSI was the reading just after installation, slowly going up as the WUR took on ambient temperature.
7.5 PSI is the lowest possible control pressure a WUR can generate.
I would like to use this unit on the 6.9, but the 380 want's it's WUR back and the vacuum hook up's are different on this more modern units.
78 6.9 #4084
79 6.9 #6669