how to tell if heads or bottom end is worn?
07-05-2006, 10:39 AM
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380 SEL 1982
how to tell if heads or bottom end is worn?
Bad new$...oil $moke from the exhau$t. How can I tell if it is the heads or the bottom end? Also, Why would this happen at only 70K (verified, it was my grandparents car)? I inherited this car and the only think I can think of is long term storage (2-4 months sometimes) and the resulting dry-ish starts. Oil was changed one to two times a year at the MB dealer and the car was only driven about 500 miles a year for the last 14 years. I put on 7K in the last year. I converted to double row chains about 9 months ago.
07-05-2006, 09:19 PM
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380 SEL 1982
are changing the valve stem seals a big job?
I have searched and read several posts about diy' ers changing valve stem seals. Does this mean that head rebuilding/replacement isn't necessary to renew these seals?
I also used about 2.5 quarts of oil in the last 1400-1800 miles.
I also hear a tapping sound from one of the valves, I don't know the cylinder but it is the passenger side (United States) closest to the firewall. I use a stethoscope and hear it loud and clear from the valve cover and exhaust outlet.
I have also experienced some sluggish off the line performance, like from 0-10 MPH. From 10 to 110MPH she is strong, solid, and smooth.
Plugs, wires, cap, rotor, ignition module, coil are all new, as are new injectors and the double row timing chain.
I will get to do a compression test shortly- stay tuned. Any early thoughts though given what I described? Partsbin has the valve stem seal kits for 14.27 and two are required for the car.....
I also used about 2.5 quarts of oil in the last 1400-1800 miles.
I also hear a tapping sound from one of the valves, I don't know the cylinder but it is the passenger side (United States) closest to the firewall. I use a stethoscope and hear it loud and clear from the valve cover and exhaust outlet.
I have also experienced some sluggish off the line performance, like from 0-10 MPH. From 10 to 110MPH she is strong, solid, and smooth.
Plugs, wires, cap, rotor, ignition module, coil are all new, as are new injectors and the double row timing chain.
I will get to do a compression test shortly- stay tuned. Any early thoughts though given what I described? Partsbin has the valve stem seal kits for 14.27 and two are required for the car.....
07-07-2006, 10:33 PM
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1987 300SDL aka the "Money Pit"
I am not that familer with the M116. I have only yanked one apart, never really worked on them much. Valve stem seals usualy are not to big of a job. On my 603, you need to remove the valve springs of course, but other then that its pretty straight forward removal and replacement.
A FSM would be a good thing to get before attempting internal engine work. These are not Chevy's, also one nees a good torque wrench.
A FSM would be a good thing to get before attempting internal engine work. These are not Chevy's, also one nees a good torque wrench.
09-01-2006, 12:05 PM
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Originally Posted by bcmbcmbcm
Bad new$...oil $moke from the exhau$t. How can I tell if it is the heads or the bottom end? Also, Why would this happen at only 70K (verified, it was my grandparents car)? I inherited this car and the only think I can think of is long term storage (2-4 months sometimes) and the resulting dry-ish starts. Oil was changed one to two times a year at the MB dealer and the car was only driven about 500 miles a year for the last 14 years. I put on 7K in the last year. I converted to double row chains about 9 months ago.
What colour is the smoke coming from the exhaust? Black, white or blue? I'll possibly be able to tell you in which part of your engine lies the problem.
09-09-2006, 07:06 PM
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380 SEL 1982
I don't remember the color
i don't remember the color, but a professional mechanic held a rag to the pipe and smelled it and so did i -smelled like oil.
09-10-2006, 02:20 AM
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280SE W116, 500SEL W126
Yes, possibly stem seals
On a low milage car you would not expect mechanical wear assuming it's been cared for) but, one that has been sitting for a long time can be susceptible to the rubber seals starting to perish, which also happens with wear
While the car is sitting for even a small period oil seeps past the seals, down the valve stems and into the combustion chamber where it's burnt-off
Often this leads to smokey start ups or when accelerating after sitting idle at lights etc
You could pull the spark plugs to see if any of them are fouled from oil getting to them, or lug the engine by driving down a slope in the lowest gear to see if it has excessive smoke, which could indicate worn rings
Normally if the heads are off the entire valve train should be renewed, valves, seats, stems, springs and the seals, even the cam oilers can be (should be) done, as well as having the heads resurfaced
Then again, I'm no expert
On a low milage car you would not expect mechanical wear assuming it's been cared for) but, one that has been sitting for a long time can be susceptible to the rubber seals starting to perish, which also happens with wear
While the car is sitting for even a small period oil seeps past the seals, down the valve stems and into the combustion chamber where it's burnt-off
Often this leads to smokey start ups or when accelerating after sitting idle at lights etc
You could pull the spark plugs to see if any of them are fouled from oil getting to them, or lug the engine by driving down a slope in the lowest gear to see if it has excessive smoke, which could indicate worn rings
Normally if the heads are off the entire valve train should be renewed, valves, seats, stems, springs and the seals, even the cam oilers can be (should be) done, as well as having the heads resurfaced
Then again, I'm no expert
Last edited by nomad; 09-10-2006 at 02:53 AM.
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09-11-2006, 08:51 AM
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things with and without wheels
If you get a chance to perform a compression check , then do it in 2 parts .
1st do it dry then do the test again with little oil in each cylinder.
If readings go up after squitring oil in there then it's the rings,
make sure you spin the engine equal amount of times for each cylinder.
1st do it dry then do the test again with little oil in each cylinder.
If readings go up after squitring oil in there then it's the rings,
make sure you spin the engine equal amount of times for each cylinder.
09-19-2006, 03:51 AM
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380 SEL 1982
thats what he said
If you get a chance to perform a compression check , then do it in 2 parts .
1st do it dry then do the test again with little oil in each cylinder.
If readings go up after squitring oil in there then it's the rings,
make sure you spin the engine equal amount of times for each cylinder.
1st do it dry then do the test again with little oil in each cylinder.
If readings go up after squitring oil in there then it's the rings,
make sure you spin the engine equal amount of times for each cylinder.
I can say with 100% certainty that this engine led a very gentle life. Oil changes might have gone as long as a year but mileage wasn't more than 1000 miles a year. During my use I did drive the car with a little gusto but I have been using Amsoil Euro 5W40 and have not put more than 2500 miles on any oil change I did. The $$ dual chain conversion should buy me some good karma in this department!
09-19-2006, 04:42 PM
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BMW E30. I've turned to the dark side.
[QUOTE=Hattaresguy;1661831]Probably valve stem seals.
A compression and leak down test would tell you whats up with the bottom end.[/QUOTE
I agree that it is pretty rare that a lower end would be the problem, when it is though, i've never had one show up on a compression test. IF the bottom end is the issue, it usually is the oil control ring that is gummed up. but compression rings are not as bad and therefore the compression test may not show it to be an issue. try high detergent motor oil and some good high-rpm driving, maybe leave it in 3rd, only as a last resort though, most likely its the valve stem seals. you'll need to measure and reset the lifter height on the noisey one. a good shop should have the special tools for that.
HTH
A compression and leak down test would tell you whats up with the bottom end.[/QUOTE
I agree that it is pretty rare that a lower end would be the problem, when it is though, i've never had one show up on a compression test. IF the bottom end is the issue, it usually is the oil control ring that is gummed up. but compression rings are not as bad and therefore the compression test may not show it to be an issue. try high detergent motor oil and some good high-rpm driving, maybe leave it in 3rd, only as a last resort though, most likely its the valve stem seals. you'll need to measure and reset the lifter height on the noisey one. a good shop should have the special tools for that.
HTH
