We have an 85 300TD, fresh oem sleeves, fresh rings and cleaned pistons. Cylinder bore measures 90.920mm - 90.925mm and are round. The engine has aprox 400 miles, but the rings simply wouldn't seat, crank case pressure/blow was excessive. So we opened her up and found this

Engine has not been overheated and has not yet seen anymore than 5 psi of boost.
The rings end gaps were with in spec.
Fuel pump timing is at 20 deg (As per Dieselmeken's specs, running his M pump)

What can cause this?? All 5 cylinders have the same wear in the same spot.

Thank you, can't wait to get this girl movin!!

Liners not bored perpendicular to the crankshaft throws? Just a guess as I am not positive.

Could the piston pin restraint clip be missing ?

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Interesting..... Never thought of that, nor do I know what the result would be. I will do some reading!

Do you mean the wrist pin retainers? If so, yes they are all installed, and installed properly.

Please keep the input coming. We are about to rip her apart and rebuild her (Again) and do not want a repeat of this failure!

GY:

Perhaps you could put up another picture or two taken from a bit farther back, so that the orientation of the pattern to the axis of the engine can be seen, as well as the pattern on the piston tops.

The dissatisfaction is tangible
While we are overcoming this set back, knowing a DieselMaken M pump and GT3076 are waiting on a healthy engine make all of us

On the way, taking them now

The FSM calls them ' piston pin lock' but the FSM is not written by a native American English speaker.

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Yes they are installed and installed properly. I had known them as a wrist pin clip.

Are you finished making and posting pictures ?
Do you have the work order showing what was done to the block ?
Was it line bored ?

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I have pictures of the entire build, far too much to post post. What do you want to see?

The sleeves were replaced, bored and honed. there was no line boring, in my experience this is reserved for when there is a need to alter the bearing size for the main caps or a new crank. This was a solid engine that was proactively rebuilt based on mileage and performance goals. If line boring would be beneficial please help me understand why.

What kind of machine was used to bore the liners ?
totally from the top ?
Or referenced to a shaft placed into the crank journals ?
The bores were made to the specs based on the measurement of the pistons which were going into that specific bore ?

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I have a feeling something math related is off here.



Did you personally measure the '90.920mm - 90.925mm' on each cylinder? I am leaning toward the shiny part of the cylinder wall (if that is the issue I am seeing) as excess piston to wall clearance. Or maybe piston rock.

What is the piston diameter of each? As I recall there were a few manufacturers of pistons and each set of six will all measure a bit different, even with the same make.

Were the rings square in the bores when you checked end gap? If so, how did you achieve this?

What is the spec on the clearance of each of ring relative to its bore? Each bore is different in diameter so each ring set will have different gaps.

Rings installed on the piston correctly per the positioning of the end gaps?

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

I do not know their process. They are a 30 year old diesel only machine shop with a solid reputation. If there is an issue with this, how would it be measured and what should I specifically ask when I speak to them? I will do some research into what you asked as I do not completely understand.