617 Engine Problem - PeachParts Mercedes-Benz Forum

1960mog · #1 08-10-2012, 09:01 PM

Hi every one

I have a 85 300D sitting at home with no engine.
So I decided to do something about it.
The question was to rebuild a engine or to buy a used one.
I bought a used one, actually a 83 parts 300SD with a running engine and 220000 miles on the clock.
After I installed that speedo in my 560SEL diesel conversion I found out that the odometer stopped working at 220000 miles.
The engine wasn't running to bad in 300SD, but I had to change a couple parts to make it a 85 300D engine.
3 injectors didn't pass the pop test, so I replaced them with better ones.
All valves were tight, but not to the point to cause compression loss in a cold engine.
After I installed the engine it actually started up, on wonder at 110+ degree outside temperature, but it had not much power and it smoked a lot.
So I removed the ALDA, that gave me more power, but didn't do any thing to the smoke.
Also the engine temperature reached the boiling point after a short test drive, in spite the fact that I installed a 75 degree thermostat.
Today I did a compression test.
280,400,340,260,320 1 to 5.
Then I did a leak down test and found that cyl. 1,3,4,5 blow out of the exhaust, and cyl. 4 and 5 out of the intake valves.
It's hard to tell the difference in blow by through the piston rings.
Well, I think I have to remove the head now and see what is going on.
At leased I have everything I need to do the job on hand.
I hope that will fix some of my problems with this engine.
And what do we learn from this???????

tbomachines · #2 08-10-2012, 10:00 PM

Quote:

Originally Posted by 1960mog

Hi every one

I have a 85 300D sitting at home with no engine.
So I decided to do something about it.
The question was to rebuild a engine or to buy a used one.
I bought a used one, actually a 83 parts 300SD with a running engine and 220000 miles on the clock.
After I installed that speedo in my 560SEL diesel conversion I found out that the odometer stopped working at 220000 miles.
The engine wasn't running to bad in 300SD, but I had to change a couple parts to make it a 85 300D engine.
3 injectors didn't pass the pop test, so I replaced them with better ones.
All valves were tight, but not to the point to cause compression loss in a cold engine.
After I installed the engine it actually started up, on wonder at 110+ degree outside temperature, but it had not much power and it smoked a lot.
So I removed the ALDA, that gave me more power, but didn't do any thing to the smoke.
Also the engine temperature reached the boiling point after a short test drive, in spite the fact that I installed a 75 degree thermostat.
Today I did a compression test.
280,400,340,260,320 1 to 5.
Then I did a leak down test and found that cyl. 1,3,4,5 blow out of the exhaust, and cyl. 4 and 5 out of the intake valves.
It's hard to tell the difference in blow by through the piston rings.
Well, I think I have to remove the head now and see what is going on.
At leased I have everything I need to do the job on hand.
I hope that will fix some of my problems with this engine.
And what do we learn from this???????

I'm not sure what you want to learn from this, but an engine at 220k is only going to be as good as its upkeep. Should have done a compression test prior to purchasing the engine, but that's too late now. It is what it is man - might be too expensive to rebuild the head as opposed to finding a new one or finding another engine with good compression. That is pretty much the ONLY thing that determines health in the engines, which is dictated by oil changes and maintenance over the years. tl;dr - what are you asking?

btw love the 'mog sig pic!

t walgamuth · #3 08-10-2012, 10:14 PM

Sounds like you need to adjust the valves. if the rings were bad it would be leaking into the crankcase the overheating needs to be addressed too. could be low on coolant, bad radiator, or bad thermostat or bad water pump. it seems premature to pull the head. pulling the head a a boat load of work.. you don't want to do that unless you are sure it is necessary.

Diesel911 · #4 08-10-2012, 11:23 PM

Quote:

Originally Posted by t walgamuth

Sounds like you need to adjust the valves. if the rings were bad it would be leaking into the crankcase the overheating needs to be addressed too. could be low on coolant, bad radiator, or bad thermostat or bad water pump. it seems premature to pull the head. pulling the head a a boat load of work.. you don't want to do that unless you are sure it is necessary.

X2 on the Valve Adjustment.

The ALDA limits the Fuel until there is Boost Pressure. Removing it would remove the Limit.

1960mog · #5 08-11-2012, 12:20 AM

Quote:

Originally Posted by t walgamuth

Sounds like you need to adjust the valves. if the rings were bad it would be leaking into the crankcase the overheating needs to be addressed too. could be low on coolant, bad radiator, or bad thermostat or bad water pump. it seems premature to pull the head. pulling the head a a boat load of work.. you don't want to do that unless you are sure it is necessary.

The valves are adjusted, and the thermostat is new.
Water pump and radiator are not, but I have a new radiator that I will install in this car.
I applied 120 pounds of air pressure to each cylinder with the rocker arms removed, and there was a pressure build up at the muffler and at the turbo inlet.
What else can that be then leaking valves, and what other way is there to fix them then to remove the head?

The car was sitting at the previous owner since 2009.
I did run the engine for about 20 minutes.

t walgamuth · #6 08-11-2012, 07:53 AM

how long were you able to run the engine before it overheated? the valves may need seating a bit more.

i'd try to run it a bit more before tearing off the head, to do that you'll need to solve your overheat problem.

Stretch · #7 08-11-2012, 11:48 AM

Quote:

Originally Posted by t walgamuth

how long were you able to run the engine before it overheated? the valves may need seating a bit more.

i'd try to run it a bit more before tearing off the head, to do that you'll need to solve your overheat problem.

I can see where Tom's coming for this. With the information given it does sound like that you've got an engine that has been sitting for a while - the valve sealing surfaces have rusted and that's causing a bit of a problem at the moment.

Please note I haven't done the maths yet - but I'll have a look at the timing of the OM617 in a bit and see if there's a position where the exhaust valves and the inlet valves you mentioned are all open at the same time.

I've just thought of this - I'm not sure if it is a good idea but how about this for a quick check? (Well it is a check quicker than head removal)

Remove rocker arms, position piston at top of bore and then remove valve springs in turn and turn the valve round and feel for any roughness. Kind of do your own lapping with the head on and without the paste. Downside to this is that the crud you remove will stay in the cylinder - whereas running it for a bit gives the better chance of it being ejected from the cylinder immediately...

...but well if you wanted to do something rather than just running it for a bit - it seems like a possible one to me!

1960mog · #8 08-11-2012, 12:12 PM

Thanks for your reply's guys.

Things are turning from bad to worse.
Took the head of this morning and found vertical scratches in cylinder # 4.
Piston or rings started to seize in that cylinder.
All cylinders are on or exceeded there 0.2 MM wear limit.
I guess it's rebuild time.
Hope that at least 4 of the pistons are reusable.
Then I can get away with one used piston, new cylinder sleeves and piston rings, bearings, gaskets, timing chain and valve guides.

Zacharias · #9 08-10-2012, 10:16 PM

How long did it sit before you got it?

How long have you run it for?

Stretch · #10 08-12-2012, 02:15 AM

That's a good picture of cylinder damage - I found it very hard to take decent pictures of damage inside cylinders...

...sorry to see the damage though. Are you going to re-sleeve it?

1960mog · #11 08-13-2012, 12:32 PM

Quote:

Originally Posted by Army

That's a good picture of cylinder damage - I found it very hard to take decent pictures of damage inside cylinders...

...sorry to see the damage though. Are you going to re-sleeve it?

I will re sleeve all 5 cylinders.
The piston from this cylinder is still re useable.
The crank looks good and the head is already done.
This will be some kind of a quick rebuild.