Ultimate OM642 build (2009 R320L CDI, 7G-Tronic)

[Ge2tis]

That conrod in the top few pics will need replacing. The bearing has been spinning inside the rod and has damaged the rod.
Given that I would be tempted to get the rods balanced (the rod weights are equalised overall and end to end) before reassembly.
I'm also not sure that crankshaft will be reusable looking at the amount of damage.

I am looking on getting all of them replaced anyway...luckily
And the crankshaft..hoping it's not damaged enough...if that's the case...a good used one is possible to source and prices are reasonable... hopefully..

 

[ajlsl600]

dirty o

I did...every single one... however I am trying to find anyone that would have a set of new ones in stock or could make one..as mine do have 180k and might not be suitable for another 180k that I plan on putting on this engine..
I found one company in Germany that has OE for around £260 per set with postage...but I have my doubts...I much rather pay a bit more and have it sourced locally...I asked a dealer and their price is £199 each...not the kind of money I want to pay for that..

dirty oil has circulated thru this engine ,maybe filter got a bit stuffed thru initial failure and relief valve opened. allowing unfiltered oil thru system. anyway the service spec for all parts will be avail somewhere, as per lk you have at least one stuffed rod .running cams have little load but i note at least one of them aint pretty, prob next to place oil first arrive at cam bearings on that head. once oil spills out from knackered bearings pressure drops everywhere else, and often top of engine sufferes you need a knowlagable crank block cyl head repairer to take a good look you want to be sure nothing re assembled without at least a reasonable idea of failure cause. does lub oil arrive from pump at centre journal or? front. its a little surprising to see one big end screwed to that extent, was it overfuelling on that cylinder ? history of smoking ?

 

[Ge2tis]

dirty o


dirty oil has circulated thru this engine ,maybe filter got a bit stuffed thru initial failure and relief valve opened. allowing unfiltered oil thru system. anyway the service spec for all parts will be avail somewhere, as per lk you have at least one stuffed rod .running cams have little load but i note at least one of them aint pretty, prob next to place oil first arrive at cam bearings on that head. once oil spills out from knackered bearings pressure drops everywhere else, and often top of engine sufferes you need a knowlagable crank block cyl head repairer to take a good look you want to be sure nothing re assembled without at least a reasonable idea of failure cause. does lub oil arrive from pump at centre journal or? front. its a little surprising to see one big end screwed to that extent, was it overfuelling on that cylinder ? history of smoking ?

I am agreeing here with you..I will have it all check by a specialist...
Not sure where the oil entry is...but it never smoked which sort of means there was no overfueling as well..or am I wrong?

 

[ajlsl600]

would say not, just trying to think on why one big end failed so badly, is piston on that cly good.does it have skirt cooling jets, you prb said ,but whats the milage. other shells damaged by rubbish comming from failed bearing methiinks ...bolts,nuts on that rod were still tight ? engine never been in bits previously?

 

[Ge2tis]

would say not, just trying to think on why one big end failed so badly, is piston on that cly good.does it have skirt cooling jets, you pnrb said ,but whats the milage. other shells damaged by rubbish comming from failed bearing methiinks ...bolts,nuts on that rod were still tight ? engine never been in bits previously?

All pistons are looking good...cooling jets, well I haven't take them out yet, but they don't look damaged in any way..mileage is 180k...other shell damage looks like foreign object damage to me too..all the bolts were tight...it does not look like it has been in pieces, but I will never know.. service history doesn't show that..however it didn't look like it's been tampered with in any way when dismantling...
Is there a way of checking the oil pump efficiency to check if it's not failed...

 

[LostKiwi]

Is there a way of checking the oil pump efficiency to check if it's not failed...

Oil pump failure will result in multiple areas of damage. Whats happened here is the bearing shell has started to spin in the conrod. This is usually down to overheating or a serious loss of oil pressure or very high internal loadings.

I did note there was evidence on one of the bores of a small amount of scoring



This would be commensurate to overheating as well. It would be interesting to see the thrust faces of that piston.

Good article about spun shells here:
http://www.enginebuildermag.com/2017/03/engine-bearing-technology-spin-spun-bearings/

 

[Ge2tis]

Oil pump failure will result in multiple areas of damage. Whats happened here is the bearing shell has started to spin in the conrod. This is usually down to overheating or a serious loss of oil pressure or very high internal loadings.

I did note there was evidence on one of the bores of a small amount of scoring

View attachment 40073

This would be commensurate to overheating as well. It would be interesting to see the thrust faces of that piston.

Good article about spun shells here:
http://www.enginebuildermag.com/2017/03/engine-bearing-technology-spin-spun-bearings/

Couple of pictures of a piston from that cylinder attached...if that's what you meant by thrust faces..

 

[ajlsl600]

Oil pump failure will result in multiple areas of damage. Whats happened here is the bearing shell has started to spin in the conrod. This is usually down to overheating or a serious loss of oil pressure or very high internal loadings.

I did note there was evidence on one of the bores of a small amount of scoring

View attachment 40073

This would be commensurate to overheating as well. It would be interesting to see the thrust faces of that piston.

Good article about spun shells here:
http://www.enginebuildermag.com/2017/03/engine-bearing-technology-spin-spun-bearings/

dont mess with oil pump new and genuine would,nt want used heart from 60 a day character if you could avoid it

 

[LostKiwi]

Thats definitely picked up a little on the bore. The pistons are iron ceramic coated and you can see the coating has been worn off in places - especially in the second photo. Is that the same cylinder with the bearing issues?

 

[ajlsl600]

All pistons are looking good...cooling jets, well I haven't take them out yet, but they don't look damaged in any way..mileage is 180k...other shell damage looks like foreign object damage to me too..all the bolts were tight...it does not look like it has been in pieces, but I will never know.. service history doesn't show that..however it didn't look like it's been tampered with in any way when dismantling...
Is there a way of checking the oil pump efficiency to check if it's not failed...

if pistons in good nic ,prob no issues with cooling jets , however if reboring remove them as process will wreck or misalign them , with unhappy results later, reason i asked about previous repair was to know if rod fastenings replaced or not as to much tightening will see them stretched, tho seems not the case from what you say. be very fussy with pre assembly inspection ,its yr last chance to spot the cause of failure dont put old oil pump back ,it gave a 180k service, dump it after yr rebuild.

 

[Ge2tis]

Thats definitely picked up a little on the bore. The pistons are iron ceramic coated and you can see the coating has been worn off in places - especially in the second photo. Is that the same cylinder with the bearing issues?

Yes, it's the same cylinder..

 

[LostKiwi]

Yes, it's the same cylinder..

Ok so that will be why its picked up then. There will be an oil jet to squirt oil on the piston which is often (don't know for sure with your engine) fed from the big end bearing. As soon as that bearing started to spin the oilway will have been covered so no oil to the bearing and no oil to the piston skirt either. If the oil squirter in NOT part of the rod then the issue was with the feed to wherever that squirter was fed from - in my guess the main bearing nearest that conrod journal. My guess is there is more damage to be found.....

 

[Ge2tis]

Ok so that will be why its picked up then. There will be an oil jet to squirt oil on the piston which is often (don't know for sure with your engine) fed from the big end bearing. As soon as that bearing started to spin the oilway will have been covered so no oil to the bearing and no oil to the piston skirt either. If the oil squirter in NOT part of the rod then the issue was with the feed to wherever that squirter was fed from - in my guess the main bearing nearest that conrod journal. My guess is there is more damage to be found.....

I hope you are wrong but it is very much possible...
So how about that piston..needs replacing or still serviceable?

 

[LostKiwi]

I hope you are wrong but it is very much possible...
So how about that piston..needs replacing or still serviceable?

I'd call it borderline... which is reason enough to change it in my book.

 

[ajlsl600]

lk. oil cooling jet runs off gallery feeding mains. or has in all cases i seen to date, a fair few. when they break off fall out or get blocked the piston gets no skirt lube, cooling and picks up . not too much evidence of this here, more like just wear of coating on skirt, normal for this milage ,i would say .

 

[LostKiwi]

lk. oil cooling jet runs off gallery feeding mains. or has in all cases i seen to date, a fair few. when they break off fall out or get blocked the piston gets no skirt lube, cooling and picks up . not too much evidence of this here, more like just wear of coating on skirt, normal for this milage ,i would say .

Ah ok. I know in older BMC engines and some Fords its a drilling off the big end hence a big end failure will manifest itself with pistons picking up as well. There is scroring on the bore that piston came from and scoring on the piston - thats the reason I would change it.

 

[ajlsl600]

that u shaped cut out in the piston is the place where that clearance is required to avoid contact with the skirt cooling lube,jet. as said given yr milage and at least on that piston ,dont think the jet a factor. keep looking. ref piston service life ,find spec ref ring gap size as in vertical max gap in ring groove .and skirt size and ovality make judgement from that spec . for me personally an overhaul i want to forget about normally involves pistons ,rings liners oil pump chains tensioners, guides all bearings and thrusts seals, gaskets . check there is now play in little ends when you slide new pin in ,any doubt change them. new valve guides and valves and seats if they cannot be refaced inside service limits there will be other items like checking out yr turbo and its opperation, but to a great extent it depends , do you want to do the job ,close bonnet and forget for 100,000 or are you happy to take a cheaper route understanding that you may wear out yr bonnet hinges ,wallet and humour .

 

[ajlsl600]

y

Ah ok. I know in older BMC engines and some Fords its a drilling off the big end hence a big end failure will manifest itself with pistons picking up as well. There is scroring on the bore that piston came from and scoring on the piston - thats the reason I would change it.

lk .cant remember seeing that .yr saying? basically there was a designed leak from the .rotating big end that sprayed oil from the big end up into the piston skirt .?yrs ago i built a old mg, that had a teaspoon like casting on the big end cap, designed to pick up a little oil as it dipped into the sump ,and flick it up the bore, quite clever and simple in its day. but not the rpm or reciprocating mass of today.

 

[LostKiwi]

y

lk .cant remember seeing that .yr saying? basically there was a designed leak from the .rotating big end that sprayed oil from the big end up into the piston skirt .?yrs ago i built a old mg, that had a teaspoon like casting on the big end cap, designed to pick up a little oil as it dipped into the sump ,and flick it up the bore, quite clever and simple in its day. but not the rpm or reciprocating mass of today.

Hers about the best image I can find showing it:

On the inner side of the bearing cap face you can just make out a drilling (left circle) and on the upper side a casting boss. The boss directs pressurised oil to the piston skirt and gudgeon pin.

Cooper S engines (without the offset caps) didn't have this as far as I can recall.

 

[EXMERCTECH]

As well as all those rods and is that scoring on the bores.
if pistons in good nic ,prob no issues with cooling jets , however if reboring remove them as process will wreck or misalign them , with unhappy results later, reason i asked about previous repair was to know if rod fastenings replaced or not as to much tightening will see them stretched, tho seems not the case from what you say. be very fussy with pre assembly inspection ,its yr last chance to spot the cause of failure dont put old oil pump back ,it gave a 180k service, dump it after yr rebuild.


I'm sure reboring isn't a option on the 642 Engines
As they are not conventional liners.
Trying to find my old Dealer Training bump to confirm.

You really need to get this engine checked by a specialist that knows these engines not just anyone.


How can it dip into the sump oil when it's on the opposite side.