New 1980 500SE Help Needed N00B!!!
 

Evening all,
I have an 81 300SD and have been on this site for quite a while now but on the diesel discussion. Just recently I bought a 1980 500SE. It is definitely a euro as it has the safety triangle in it, headlight height adjustment, and the cruise control stalk is in German. Of course a 500SE was never available in the US either.

Now of course I have some questions. The main one I have is with the motor. Whats happening is that the motor smokes. Pretty bad when its revved. It is white. I took the plugs out tonight and definitely plan on replacing those, the wires, rotor, and cap. Since I have owned the OM617 for the past year or two I lack the knowledge of what a good spark plug looks like. Here they are.....
http://i196.photobucket.com/albums/a...n/P9200058.jpg
http://i196.photobucket.com/albums/a...n/P9200057.jpg
http://i196.photobucket.com/albums/a...n/P9200056.jpg
http://i196.photobucket.com/albums/a...n/P9200055.jpg
http://i196.photobucket.com/albums/a...n/P9200053.jpg
http://i196.photobucket.com/albums/a...n/P9200051.jpg
http://i196.photobucket.com/albums/a...n/P9200047.jpg


I definitely have some more questions but I have the FSM for the 5.0 coming in the mail. Thanks in advance.

Drew

The plugs don't look old enough to replace - check the gap.
Check your plug wires - When it is dark, mist(spray bottle/plant mister) the wires, and look for arcs.
If your oil isn't coffee colored, and your coolant doesn't have black spot floating in it, I would lean towards needing new valve seals.

BTW...are those non-resistor plugs? Who made the wires? (see sticky about non-resistor plugs)

Larry,
Would you happen to know the gap off hand for the M117? The plug wires are Bosch and seem to be original. the oil definitely needs changed and is a light brown color. I couldn't get a good look at the coolant as the level is low but I will check tomorrow. The plugs are probably original. They say Bosch Super W9DC Made in Germany. The car only has 79,000 miles on it, but it has sat for the better part of the last 5-6 years.

.036 or 9mm (.040 wouldn't hurt)

Spark plugs don't look bad to me. According to a book I have the two most common sources of white smoke are transmission fluid and antifreeze. For the transmission pull the vacuum hose off the vacuum modulator and check for transmission fluid in the hose - if so replace the vacuum modulator. Antifreeze source is most likely blown head gasket, cracked head or cracked block. Do a compression test or better yet leak down test. Antifreeze smoke has a distinct sweet odor, transmission fluid just smells smoky.

I just did a quick bench test and all of them were tight. I couldn't even fit the feeler gauge in between the electrode. I will regap and re install tomorrow. Should this help a little?

Clean them up a little - get that black crud off of there. The crunchy stuff is carbon - might do some good to get some nice premium fuel, and drive it like you mean it.
Hard to say if you will notice the difference - you may, you may not...you may notice it at speed... you might only notice it at the pump.

The two middle plugs on the right look best. The ones with dark colored carbon havent been firing all that cleanly and the one that is oily looks like possible trouble, but if you wires are bad this could be causing it. I would run it in the dark and look for sparks along the wires.

A compression test would be informative too.

Tom W

1 and 5 are a bit rich (maybe indicating misfires or bad wires), 3 is a bit oily looking (maybe indicating a valve stem seal), but honestly they aren't bad. You do NEED premium in a euro 500 though and it looks like that hasn't been happening in your engine. Run it till it's almost empty, put in a bottle of fuel injector cleaner and 5 gallons of 93 octane, and go on the highway. Gun it at 70 and keep it floored, it should downshift. Keep the pedal gunned until it shifts into the next gear, and don't be afraid of overrevving an M117 in that fashion, it's something you really should (maybe I should say "Need") to do to keep it clean! Keep doing this until your exhaust doesn't spew out black smoke like crazy.

FYI, it might not stop spewing out black smoke ever doing this. Your exhaust system might be coated with years of crud.

white smoke
 

white smoke can be caused by transmission fluid belng sucked up lnto the intake manifold through the line to the transmission modulator .

Well I cleaned the plugs and did a compression test this afternoon. I am pleased with both results. The clean plugs got rid of the stumble and hesitation in the motor which I figured they would. The compression results I think were very good too.

170 160
165 150 <-- Drivers side
170 150
170 140
|
Fan V

Is the driver's side front cylinder anything to worry about?
It runs real good now except for the 2k idle speed and the fact that I seem to fog for mosquitoes every time I start her up.

If you sit at a traffic light for a minute, and then start to go, do you get a puff/cloud of smoke?

It is very wierd. I worked on it all day today and it still smoked. Then I put the air cleaner asembly (sp?) back on and the smoke went away. I took her for a ride tonight and good lord does she have power. I will check for the smoke at a stop light tomorrow during the day. Tomorrow I will probably tackle brakes and trans. Any advice on hard downshifts and long up shift times?

I also filled up with some 93 octane and it likes it much better.

If it has the mechanical link between throttle and transmission, it needs to be spot on or it will cause problems.

Blue smoke = oil
White smoke, dissipating within a few feet = water (coolant)
White smoke, fogging the neighborhood = transmission or brake fluid.

Michael

check for correct plugs those are for 300 SE
I;m thinking the 500 should have wd8..hotter...?