Are you sure about those numbers? I doubt an engine would run at all with compression that low.

well one thing to take note of is when i removed the glow plugs and cranked, in an attempt to remove the marvel mystery oil i poured in, i didn't really see anything come out any of the holes. i did notice some smoke or steam coming out of cyl #4, not sure what it was. blowby?? so maybe the rings are gone and that stuff just leaked right into the oil pan.

tomorrow i'll re-check the valves.

if the head gasket is blown, is shaving the head needed? or can i just put in a new gasket?

i know there is no "easy" way to do it but is it possible to replace the rings without pulling the engine? is it just a matter of pulling the head and oil pan and popping out the pistons? if i were to go this route, could i order new rings from fastlane? i assume i'd also need to get new bearings for the crankshaft. would i need a new timing chain as well?

if it comes down to it i really wouldn't mind rebuilding the engine in this car. and i know this stuff isnt that hard to actually do, its just having the right tools, procedures, and patience. although i'd think these issues would have shown up sooner, not be caused by a glow plug reamer! worst $30 i ever spent!

__________________
1981 300SD, 270K, two tank wvo system
1985 300D, 288K, california version
1985 300DT wagon, 315k, broken odo

U get approximately 2*F increase in temperature for each PSI of pressure.

Therefore U can see that with the compression numbers U get, the temperature inside the cylinder is way below the ignition point of the fuel.

Try a shot of starting fluid and see what happens. It has a much lower ignition temperature than Diesel fuel.

P E H

I was in a hurry to do the compression test. I only tested each cylinder once. The tester i used was a cheap $20 harbor freight tool.

After cranking to try and get the marvel mystery oil out, i replaced the glow plugs but left the harness disconnected. I tightened them in by hand, and then snugged them down with a wrench. I didn't tighten them super hard; should i have done that? I then had to assemble the parts of the compression tester. There was a black piece that looks like the bottom half of a fuel injector, and then there's a little 1/4" threaded quick release fitting that screws in. I was in a hurry so i just screwed it in, i didnt use any teflon tape. I got it as tight as i could with the 1/4 drive socket wrench i was using. Then i just cranked, about 10 revolutions per cylinder.

Maybe i should have repeated the test a few times, its been well over 10 years since the last time i used a compression tester so i didnt really remember how im supposed to do it.

I took the readings with a grain of salt as its always started when I was in California, and i had just recently driven it from San Francisco to Seattle and back, and then to Denver where i'm currently staying. In all that driving i never had any starting issue. The cold starting issue just started recently, the first time we had snow here.

I got sick of being "snowed in" on cold days, so I tried to think of ways to make my car start in colder weather. Reaming the glow plugs was the first thing that i thought of. I never had an issue starting it here before on warmer days.

__________________
1981 300SD, 270K, two tank wvo system
1985 300D, 288K, california version
1985 300DT wagon, 315k, broken odo

to do list for tomorrow:

• WD-40 (how long should i spray for?)

• starting fluid w/ glow harness disconnected

• check valves

• pull start? (20 mph for a couple minutes, then slam it into the lowest gear)

__________________
1981 300SD, 270K, two tank wvo system
1985 300D, 288K, california version
1985 300DT wagon, 315k, broken odo

Good, adjusting valves is the simple/cheap answer.
Hope it works for you.
I have had the valve gap move from good to bad in five minutes running, with a set of bad nuts.




Generally it is just a bad head gasket, you should have the head serviced while it is off = valve guides, grind valves/seats, and new valve stem seals.
They can check pre-chamber depth and correct as needed.


If the rings are that bad = new cylinder liners + boring = pull the engine.

Piston Ring Set, (five sets per OM617 engine) Standard (90.90 mm) 3.0 - 2.0 - 4.0
MB# 003 030 24 24

Cylinder Liner, (five per OM617 engine)
MB# 616 011 12 10

Piston (standard.)
MB# 6170301017

Piston (0.25)
MB# 6170301117

Piston (0.50)
MB# 6170301217

Call for the curreent price on the pistons

__________________
ASE Master Mechanic
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Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
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Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

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The reason perhaps now the compression is well below starting minumins. The vegatable oil scraped off the walls over time is not good in itself around the ring lands and rings.. I noticed that another engine unused for a short period of time had a simular issue.

The byproducts of the vegatable residue seem to turn a sticky mess into a glue like substance in pretty short order. Probably just drying out with the engine not in use. Perhaps some kind of chemical action. Who knows?

The head gasket is probably okay as the problem is across too many cylinders. I would attempt to pull start the vehicle with a couple of quarts of mystery oil in the crankcase. Remove some of the normal oil if required to stop going too high on the dipstick.

If car starts and runs dump two quarts of the mystery oil in the fuel tank. Run the engine for an hour or two. Since the engine only burns a quart or little more per hour at idle let it idle for several hours.

Between the introduction of the solvent and the heat it should do a preliminary ring release if the glue will disolve. Shut the engine down and try a warm restart. If it will start shut it back down again and pull the injectors. Put more mystery oil in. The rings may have let go enough to retain some mystery oil in their vicinity now. Anyways soak the rings again if possible. Then check compression. What have you got to lose? With a lot of good coincidence you might be in fair shape.

If the general compression were that low from normal ring wear I would expect the bores to be questionable. Putting new rings on poor bores is also a very short bandage type approach.

It s almost certain this is the sequence of events. The engine could not have been running the last time at these compression levels. They have gone or appear to have gone a long way downhill since the last time the engine was used. I can think of nothing you may have done to cause this.

You have a PM..



Links for Tow or Push starting 1985 and earlier MB Diesel
Links for Tow or Push starting 1985 and earlier MB Diesel

As I recall, the injector adapter on my HF tester does not have a schrader valve and has a huge cavity that will not give you the correct readings. I'd suggest doing the compression test again via the glow plug holes. You will have to remove the injector hardlines for access. There are straight and elbow adapters for the glow plugs as I recall. Pick the combinations that are easiest for a particular hole. Pull all glow plugs for higher speed spins and charge that battery up good. Keep spinning till the gauge maxes out. Probably around 20 revs? The gauge should hold pressure after engine stops spinning. If the reading drops slowly, you have a leak somewhere but the max reading is still useful.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Talked with "Biotour" 03:09 AM 12-23-2009...

Due to weather (Denver snow), he will be staying inside for two days..

When possible he will:
* Compare starter cranking speed to his friends 300D.
* Check, and adjust valves as needed.
* Do a (glow plug) compression test.

new owner of a 240D


Have a read of the two links I posted concerning gummed rings,some very good results were obtained with water injection virtually removing the problem.

First post in the link.

The difference between sea level and a mile high could be enough to drop your compression down to the level where it fails to start. Combine that with removing carbon from the combustion chamber and the results aren't good.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I'm reluctant to add any more wild geese to chase, but couldn't a timing problem be the issue? Layback suggested as much way back on the second page. If the timing's off, the valve's won't be right for a compression check, it'll be hard to start, etc.

Reaming the plugs shouldn't have had any effect on timing, but it may be pure coincidence that something happened with the timing chain. I'd look at that before getting into replacing head gaskets, rings, etc.

Coincidentally, I just did similar maintenance with similar tools and had no ill effects. Just prior to that we had our first cold snap in Texas, and my car was hard to start. I reamed the glow plugs holes, tested 'em and found a bad plug, didn't vacuum but replaced everything, bled the lines and it started up.

However, I'm contemplating pulling or checking the prechamber since I've now seen tiny bubbles near the ring after bleeding the hardlines. A huge difference between his results and mine is the monster compression values I get with the same $20 HF cheapie gauge: on a warm engine I got 440, 420, 390, 420, 440. The 390 is the one with the tiny bubbles.

But - it was my first compression test and I dorked it up the first time. I used the glow plug holes and did not have all the fittings tight - so that's one more thing I'd suggest checking. I cranked it over a few times and saw a measly 180 psi and was disappointed, but then I realized the needle kept dropping so I figured there was a leak. So I tightened everything up, let it crank till the gauge stopped climbing (maybe 10 seconds per cylinder?) and was happy with numbers.

I'd reconsider Occam's Razor: when considering two possible causes for the same event, the simpler solution is probably the right one. I'd add a timing check to WHunter's list.

Since these things are compression ignition engines they have certain demands for creating the conditions necessary to start, at all, and when these conditions are not met, the engine won't start. In cold weather the margin for degraded performance is slim to none.

The term "compression ignition" means you need to compress the air in the cylinder enough to raise its temperature to at least the temperature that will ignite an ideal mist of Diesel fuel. So, compression is important. Ambient temperature affects the need for ideal compression - the lower the ambient temperature the more challenging it is for a cold engine to achieve the "inside the combustion chamber air temperature" needed to ignite Diesel fuel. The reasons are that the heat of compression is being sucked into the block and head - the colder the ambient temperature the more heat is absorbed. Also, the longer the compression stroke takes, the more heat is absorbed. And the more leakage past the rings and valves occurs. Even a perfectly new engine, if turned slowly enough, won't generate sufficient heat from compression (there won't be enough compression) to ignite Diesel fuel. So, poorly valves, improper timing (chain stretch) and a weak starter stack the deck against you.

The next big things, and often the most significant, are glow plugs and injector condition. Glow plugs are there specifically to raise the temperature in the prechamber to achieve ignition of the fuel. This is easier if the fuel is properly atomized. If the fuel comes out in globs or a more liquid stream than fully atomized, the likelihood of ignition is reduced. You can put a match out by dripping cold, chunky Diesel/paraffin globs on it. A steady stream of Diesel on a glow plug will just cool it off as the Diesel evaporates. Besides ensuring each glow plug has the correct voltage, reaming the bore of the glow plug hole ensures there is not a heat short to the block. Carbon is pretty good as a conductor, and if the entire glow plug is bound to the head by a carbon filler, the glow plug tip temperature will be reduced by the amount of heat being conducted directly into a cold head.

I think you are pretty certain your glow plugs are operating and your injectors work fine. That would take care of two potential areas of degradation. Low performing glow plugs don't provide the heat necessary to make up for the starting conditions, and it is not clear to me from what has been written (or read by me) that the glow plugs were in good operating condition even after you installed brand new ones. A couple of non-functioning plugs and these engines don't want to start in cold weather.

So, it would seem you have possibly introduced some flakes of carbon into the valve to seat ring interface, preventing the valve from entirely seating. Or your valves are mis-timed due to a stretched chain, or, they are just not properly adjusted, if they are the adjusting variety. I forgot what engine you have but the later ones (6 cylinder models) may not require manual adjustments as I think they have lifters. A bad lifter may also be involved.

If you suspect your starter is weak, you should consider changing it out. When you remove it your choices are to have it rebuilt locally or have a rebuilt one provided by a local parts supply, FastLane or buy a genuine new one. I caution you to be careful here. Most alternator and starter rebuilding houses don't actually rewind and re-insulate the motors. In fact, most of the work done is mechanical in nature (replacing brushes, solenoid/Bendix, bearings and commutator refinishing). Yet the most serious failures come from tired insulation. A starter is rated for intermittent duty. Meaning, they would burn up, literally, if run at that starting cycle load continuously. Since they are relatively small and have a small thermal mass they can only run at starting duty load for a short time. At lower voltage they draw more current to try to make the same output power and heat up faster. So, they are sensitive to abuse. Bad batteries and long cranking sessions means the insulation degrades, permanently. Changing brushes or refinishing the commutator strips doesn't address the problem of degraded (current leaking) insulation. Neither does a new bearing. So, I don't buy cheap rebuilds. I try to buy only Bosch rebuilds (I believe Fastlane has these as I have had good luck with their source in the past) or have a local guy who rewinds them do the job (rare option). Or I just buy a new starter. Alternators are less of a concern and have a few more electrical parts that go bad (diodes). And they are not intermittent duty rated and therefore do not get subjected to the same kinds of abuse that eats insulation life.

Even if the starter is not weak, for winter months the oil should be a good grade of synthetic. I highly recommend Mobil Delvac 1, a 5W-40 full synthetic. Others have had good results with other synthetics. But the point here is that the load the oil pump puts on the starter is not trivial in cold weather. The oil pump is a variety of positive displacement pump, which means in a given turn of the pump shaft, a given volume of oil is moved into the system from the sump. If the oil is particularly viscous because it is cold, it resists flow. And the torque demand from the starter increases. The colder the oil the more from the starter it demands, slowing the starter down. Which then allows the normal leakage of air being compressed past the rings and valves to increase, lowering the compression and the resulting heat, which is also given more time to get sucked into the cold steel block, the pistons, and aluminum or steel, head.

So, a slowly turning engine is going to make your compression test meaningless. And, if the battery was allowed to get tired, and you cranked a lot to start the unit, chances are you were not going to start it unless you schlepped it with another car or truck and forced the tranny to turn the engine over in "Drive" or "Low" at a high rate of speed.

In the end, higher cranking speed will overcome all other ills. I have push started a manual transmission equipped, 1971 220D in -10F weather in under three car lengths after it would not start with an AAA tow truck with the fattest jumper cables I ever saw. So, read your owner's manual. I believe it will tell you how to push start your car even with an automatic. Maybe not with one of these new automatics. But the old ones told you how to do it.

Good luck, and I hope this helps.

Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

i hope everyone had a good christmas! its still freezing here so i haven't done as much to the car as i would have liked. tomorrow its supposed to be a little warmer out and i'm going to pull the valve cover and check clearances. i'll also try and get the notches on the cam gear lined up and see what my timing looks like. i don't have a dial caliper so im just going to do it the "lazy" way.

today i pulled the starter and put in a remanufactured autozone one to see if there was any difference. after comparing starter speed between my and my friends 300sd his seemed to turn the engine over faster, and i thought mine may have just been burned out. it now turns over slightly faster but she still won't start.

i'm using a full synthetic 5w40 oil, and this is the om617 engine so i don't have hydraulic lifters. i traded in my month old battery for another brand new one, so i know the battery isn't the issue here. i will also order a lower radiator hose style block heater, anyone have a good source? does fastlane sell these?

heres a video of my car trying to start today after putting in the new starter:

http://www.youtube.com/watch?v=4IYgTEhx_to

__________________
1981 300SD, 270K, two tank wvo system
1985 300D, 288K, california version
1985 300DT wagon, 315k, broken odo