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.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

X2 on the Valve Adjustment.

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

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84 300D, 82 Volvo 244Gl Diesel

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.

__________________

76 240 D. Bought in 1998 for $25.
85 300D. Got it for free with a bad engine. ( Sold )
60 Unimog 404. What was left of it, was given to me. Now powerd by 617A.
88 560 SEL. Bought without engine and trans. Now powerd by 617A.
67 250 SE. Cuope. For resto or sale.
64 220SE. For resto.

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.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

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!

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

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.

__________________

76 240 D. Bought in 1998 for $25.
85 300D. Got it for free with a bad engine. ( Sold )
60 Unimog 404. What was left of it, was given to me. Now powerd by 617A.
88 560 SEL. Bought without engine and trans. Now powerd by 617A.
67 250 SE. Cuope. For resto or sale.
64 220SE. For resto.

Well that piston might not be dead - check it out first. There's still hope!

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Yes, # 4 cylinder was still running when I checked the cylinders by opening the injector lines.
May be it's just the rings.

__________________

76 240 D. Bought in 1998 for $25.
85 300D. Got it for free with a bad engine. ( Sold )
60 Unimog 404. What was left of it, was given to me. Now powerd by 617A.
88 560 SEL. Bought without engine and trans. Now powerd by 617A.
67 250 SE. Cuope. For resto or sale.
64 220SE. For resto.

Now I have a question.

I have 2 electrical connections in my 85 300D that don't have a hock up on the 300SD engine.

The first one looks like it connects to a temp sensor.
It is in the harness that connects to the micro switch on top of the valve cover.



The second one comes out of the glow plug harness.
It exits the harness with the wire for the first glow plug and also looks like it connects to a temp sensor.
I am sure one of them connects to a sensor in the front most plug in the head, bud where dose the other one go?

Thanks
Tom

__________________

76 240 D. Bought in 1998 for $25.
85 300D. Got it for free with a bad engine. ( Sold )
60 Unimog 404. What was left of it, was given to me. Now powerd by 617A.
88 560 SEL. Bought without engine and trans. Now powerd by 617A.
67 250 SE. Cuope. For resto or sale.
64 220SE. For resto.