2.0 8V bottom end rebuild (by idiots)

[Citjon]

The OPR / 'ORGA' number is stencilled onto the left front A post, and is visible when you open the door. It translates to the day of manufacture and can be looked up online via several websites if needed.

When ordering parts it is obviously crucial to observe the correct OPR reference for your car. 05897 gives a date of 31 December 1992, so a few years after production started.

Hope this helps for future reference.

[eyesoreracing]

@Dieselman, way back at the beginning of this thread you gave some helpful advice I'd like to revisit.

First:

Doesn't sound like you're an idiot...

Care to rethink that one now?

Official workshop manuals are linked here http://files.cinnamoncars.com/citroen/xm/mec.html

Are you able to see this link? For us, its a server-not-found error. We used the Peter Russek manual, but it has some gaps. Its helpful enough to mention that the rod bearings changed widths over time, but we're hoping for more details that might help us decipher the situation.

So far King Bearings has a different US site where they do list this engine, but don't list any rod bearings. Only mains. Your link went to main bearings too. KM lists rod bearings, but has nothing in stock.

[Dieselman]

I still don't think you are idiots, you were caught out by the available bearings having been changed after the R6a engine. I wasn't aware of that and your experience is a valuable lesson for us.

For the manual, I thought you had the Haynes manual as well as Peter Russek...? Check your inbox.
Haynes suggests big end running clearances of 0.025-0.050mm as typical values. No specific ones given at the time of publication.
Should we take it yours are 0.038mm? It's not clear from your image.
What is happening is the oil is escaping from the edge of the bearing journal, due to it not reaching edge of the crank journal, so the oil not being dammed.

For the genuine one go to http://www.ckc.dk/cgi/catlist?modl=YA%2 ... s&xlang=da

Contact each of the manufacturers, I'm confident someone will have these, it's a pretty common engine and these won't be unique parts, they will be shared with other engines.

It would be worth checking the oil pump and relief valve are functioning properly and delivering full pressure. I know you have cold pressure, but maybe hot pressure is inadequate not only as a result of the bearing shells.

[eyesoreracing]

I think the relief valve might be the real root cause of the problem. Last night I disassembled the pump and found the relief valve piston doesn't move smoothly. First, the bore is very poorly machined.



Second, the piston has some scuff marks that suggest it may have wedged itself crooked in the bore from time to time.



This is a stout engine by design, but the casting and machining quality is the worst I've ever seen. This rough machining is terrible, but is probably only #4 on the list of factory quality horrors I've seen in this thing.

Anyway, the bearings are definitely showing some wear from this adventure, but they're not destroyed yet, so I'm going to sand off the rough edges on the bore and piston so they move more smoothly, install an oil pressure gauge, and throw it back together before shipping more parts from Europe.

I did have the forethought to measure the old and new bearing widths when I saw they were different. The gap is not the 5mm I was expecting. The old bearings were already small for the rods, and already offset to one side. The rod is made to accommodate a 25m bearing, but the original was 21.8mm and the new ones are 20.1. Bearing clearances are 0.038mm, so we seem to be in the normal tolerance range there.

[Dieselman]

That pressure relief valve does look suspect, maybe that was the original problem and maybe it's not the original one.

Check the crank journal sizes, but these appear to be the correct big end bearings, as they are 21.95mm wide. There are others with similar dimensions.
It also gives the clearance values as 0.03 to 0.08mm
https://www.kmotorshop.com/en/article-d ... ps19939000

It seems King do make some shells for this engine: P/no CR4306SI and an alternative, MB5129SM. Have a read through the technical data and cross reference tabs, it gives useful information.
https://www.king-catalog.com/Catalog/Engine/614700

Use engine code XU10J2 for searching. XU = petrol engine, 10 = 2 litre, J2 = 2 valve per cylinder.

Looking at the parts diagram suggests the oil pressure relief should be at 6 Bar. https://www.catcar.info/citroen/?lang=e ... BwbGllcj09

Like you, I suspect what is happening is the cold oil pressure activates the pressure relief valve, which then sticks slightly open and as the oil heats up the pressure then drops below operating pressure.

[eyesoreracing]

Since the bearings are still serviceable for now, I'm putting the engine back together for more in-use diagnostics. I polished the piston and rounded the edges as much as possible before reassembling the pump.



We've also learned a bit more about the circumstances that let this car run low on oil in the first place.

For one, of course, the pump may have intermittently been hanging up even before the fateful road trip from Florida to California where it ran down to 1/2qt of oil and did all the bearing damage. Some of that damage may have happened back in Spain.

Second, we found the oil level sensor wires had melted and were intermittently shorting together, which explains why the oil level readings were erratic.



Third, the oil pressure light fails off. Meaning that if the cheap plastic connector rots and falls off, the light doesn't come on! It will only come on with a good connection and no pressure. It was rotten and loose. But we also found that no oil pressure light came on when we were actively hearing rod knock, so it may also be calibrated incorrectly and will stay off even when oil pressure is too low to maintain bearing function.

Finally, the dipstick... I think it was just hard to interpret for a new owner. Since the dipstick tube does an S-bend on the way up from the pan, it gets oil smeared all over the stick. If you have oil, one side will have a clear line, while the other will have a smear. If its low on oil the first time you check it, it will just have smears and will be hard to undertand...

That said, we filled the oil after reassembly to the specified amount, confirmed the level on the level sensor, but the dipstick still read low!



I'm not sure if this was the situation originally, or if it was caused by us struggling to get the dipstick tube back in the engine while the engine was in the car (if you remove the tube, definitely put it back in before you put the engine in the car!) The tube doesn't fully seat in the block. The stopper ring that is supposed to sit against the block is sitting a little above the hole. I can feel this with my finger, but it can't be seen, as this whole situation is hidden in the engine mount/carrier bearing block on the back of the engine block.

So that brings us to the diptstick:



I'm considering just getting a universal dipstick and adjusting it to our new reality. But meanwhile, if anyone can confirm if this original dipstick is even the correct length, that would be nice to know.

I also think the dipstick may be part of our erratic idle behavior. The rubber top of the dipstick was split in two and held together with electrical tape. It clearly isn't sealing properly in the dipstick tube, so I think there is an unmetered air leak in through the dipstick tube, through the crankcase vent system and into the intake manifold. This is my biggest motivation to get a new dipstick...

[eyesoreracing]

Confirmed! It does idle better with the dipstick tube properly sealed!



We're up and running again with an oil pressure gauge temporarily installed. It'll be a day or two before I drive far enough to warm the oil and confirm if hot idle is still rattling rods.

Meanwhile, here's the only decent pic of the car so far, next to its equally eclectic garage buddy.

[Dieselman]

Well done on the pressure relief and other repairs, both cars look great and the Xm with the oil gauge is proper drag strip style.

From memory the distance from the bend at the top of the dipstick to the top of the dipstick tube is 22mm.
Overall dipstick lengths are given in the linked to post: I think yours should be 674mm from the top of the dipstick tube to the Low marker, with 20mm between Low and High.
Try adding some rubber hose round the upper part of the dipstick as a seal and attach a knob. Synthetic wine bottle corks work very well.

See dipstick length thread for detail.

viewtopic.php?f=6&t=9198&p=130668&hilit ... ck#p130668

Mecaplace are making dipstick tops. https://mecaplace.com/produit/kit-pour- ... injection/

[Dieselman]

We're still struggling to set the timing. We found the mark on the flywheel (under the intake hose, suspension hoses, and a chaotic tangle of wires), but the timing marks on the bellhousing seem to be a series of 5-degree (?) increments with no clear indication of which one is TDC.

Best I can do for now is a small illustration. TDC will be towards the front of the car, advancing markers will be further back.

[Dieselman]

As a matter of interest, did you polish the crank journals before installing new big end shells?