2.0 8V bottom end rebuild (by idiots)

[eyesoreracing]

Hi everyone, I'm an idiot.

I, and my idiot friend will be attempting to fix the engine in his 2.0 8V, manual transmission XM. Everything about the car is perfect except for the complete lack of compression in two cylinders (and a hint of rod knock. And that bearing noise in the transmission...)

We both know which end of a wrench to swing, but we've never had a Citroen apart before and we're hoping for helpful advice on pulling the engine and tearing it down. I'm assuming we'll need to pull engine and transmission as a unit and separate them on the ground, but if you can pull just the engine, I'd love to know that now. I'd also like to know that we don't need to remove the A/C compressor, or the magic suspension pump thingy.

We won't start work for at least another week, so you have that much time to tell us all the helpful things we'll need to know. Or talk us out of it.

Merci in advance.

[Dieselman]

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

You can actually rebuild the Xu10 engine in situ, as long as you don't need the crank out of it, but seeing as the gearbox needs an input shaft bearing, just pull both units and go for it.
You can either unbolt the complete nosecone and swing the drivetrain forwards and out, or leave the nose on, disconnect the bonnet gas struts and raise it to vertical, then lift the engine. You may need to remove the grey scuttle trim to allow the bonnet to raise to vertical. There are no latches at vertical, so secure it.

The Xu10 (2.0i) is a really simple engine and very easy to work on.

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

The Haynes manual covers all you need and the Peter Russek manual is linked to here viewtopic.php?f=13&t=10603
Haynes is easier to read so look online if you don't have one.

Don't worry about the hydraulics, it will probably take longer trying to leave them in situ than it takes to reconnect them. Disconnect the regulator pipes and lift it out with the engine.
Take a picture of the hydraulic pipes connected to the regulator and FDV before disconnection, so they go back on in the correct order. Only undo the ones that go to the body.
The engine loom connector is under the Lhm tank, just behind the battery box.

After checking the reason for lost compression, valves, or rings, I would probably remove the cylinder head and check the bores. Take the manifolds off with the head.
If it needs re-boring and the crank grinding, remove the block, if not leave it in situ and install new rings, bearing shells, etc.
The oil consumption is likely to be the valve guide seals are worn out, could be more, but check before condemning.

Engine machining is cheap, having an engine builder rework a complete engine is very costly. Perform your own labour, it will be fun and you will learn a lot.

[eyesoreracing]

Wow, this is precisely the information I was hoping for. This will give us a great head start so we can avoid early mistakes and just focus on making big mistakes. Thank you!

[Dieselman]

Most of us have made much bigger mistakes than you are going to.

Regarding the crankshaft, you can polish the journals using wet and dry paper and sneak new big end and main bearing shells in with it still mounted, but if you really need it out, can push the gearbox on top of the subframe, then remove the flywheel and crank. I would aim to install a new main crank seal while you have access.

[bump_drft]

We've removed everything but can't seem to get the gear linkage to disconnect, does anyone have a trick? Is there a nut I'm missing on it?

[Dieselman]

Use a small pickle-fork, or other two pronged implement to prise the sockets off the balls.

[eyesoreracing]

We pried and pried and had no luck, so we finally drove out the roll pin holding the linkage to the transmission and left the whole mess in the car. Certainly not the easiest way to do it.

We did a lot of things the hard way, since we have no experience with french cars and kept running into unfamiliar things.

Basic question: How should the axles come out?

On the driver's side, we popped out the axle from the transmission with a prybar, but to get enough travel to pull it free, we removed the lower ball joint and swung the wheel out.

On the passenger's side, we couldn't figure out how to separate the axle from the engine/transmission, so we finally removed the inner boot and pulled the joint apart.

What should we have done?

[Dieselman]

The driveshafts are held into the differential with a hog ring.
The shaft "should" just unclip and pop out when pulled, but can be rather difficult, especially if they haven't been apart for some time. Do as you did, slip a pry bar between the inner joint and the gearbox casing and shock it out.

As you found, undoing the lower suspension ball joint gives room for the driveshaft to be withdrawn, but I have heard of a tip that raising the hub unit until the driveshaft is level and at maximum length, then turn the hub to full steering lock, might just give enough room for the stub to be withdrawn from the bearing without having to part the lower ball joint.

For the R/h driveshaft undo the intermediate bearing from the carrier, then remove the inner joint from the gearbox, as for the left side.

I think the reason you struggled was that the driveshaft was still mounted in the wheel bearing. Remove the shaft from the wheel bearing and it allows a straighter pull, with no resistance, to remove the complete shaft from the gearbox.
These driveshaft fixings are re-useable, unlike VW ones where the nut is destroyed on loosening.

The gearbox linkages not wanting to part is a good sign. Eventually they wear to the point they fall apart on their own. Keep them lubricated, with suitable grease, to avoid wear.

Don't worry about it being a European car, apart from all hardware being metric, everything is the same as any other car...even US domestic ones.

Are we going to see images of your trials and tribulations, or maybe a YT video? It's Ok for grown Men to cry on film...

[bump_drft]

Looks like the head gasket failed betw cyls 2 and 3, which makes sense since they had low compression



Bottom end looks surprisingly good!





It will need bearings I'm sure, as there was a ton of bearing material in the oil. I assume head will need resurfacing.

This car has had a rough life and to go from plodding around Marid it's whole life, to suddenly driving across the US, is kind of remarkable.

[Dieselman]

The bores appear Ok, check to see if there is a wear step at the point the piston rings don't travel over and see if there is still any cross hatching left.
Lack of compression on two adjacent cylinders is normally a blown head gasket, how long was it running like that? Are there any signs the head, or block have been eroded by hot gasses?
You might need the head skimming, clean it then check with a straight edge and feeler blades, also check the block face, which is less likely to be affected by heat due to being cast iron.
If you are feeling super economical (tight), you can flat the head by using a sheet of emery paper stuck to a flat surface, or some coarse grinding paste on a sheet of flat glass, then slide the head over it to rub it flat.
If the head is warped, it's best to press it flat again after heating, before skimming, that way there is less metal removed. Ensure the camshaft still rotates freely after pressing.
A worthwhile video.

It will be interesting to see the crank journals, you may have got away lightly and just have a bit of polishing to do. Use wet & dry paper wrapped right round to polish the journals.
It might be worth installing new piston rings while you have access, but they may be fine. Most compression loss is due to valves not sealing, so check the valve stem clearance in the guides, lap the valves into the seats with grinding paste, install new valve stem seals, which normally come as part of a complete "head set"
You need to carefully check the tappet adjustment once the valves and cams are back in place. Keep all the shims in order for now and measure with a micrometer, or accurate Vernier. It sounds tricky, but is easy in reality. you will find you can move shims around to obtain the correct clearances with only having to purchase a minimum of new shims. An engineering workshop can regrind over-size shims down to the correct thickness and often supply new shims.
Shims vary from 2.225mm to 3.55mm.

So far, it appears you have escaped major disaster and should be able to fix the engine with fairly minimal cost.
The most important thing is you are actually getting on with the job.

There appears to be only one head gasket, P/no 0209 N1
Valve grinding gasket set P/n 0197 C9
Separate valve stem seals, which do come in the valve grinding gasket set. P/n 0956 22.

For the gearbox the input bearing is P/no 2372 40, which is a standard ball race bearing, 25 X 47 - 15
Input shaft seal is P/no 2109 40, standard lip seal 23X36-6

If you need any seals for the hydraulic system they are standard Citroen 3.5mm and 4.5mm seals for Lhm, fitted to every Citroen since Ds in 1955 to 2010. 2Cv use the same seals.
If you really can't obtain any, buy some suitable hose and cut your own to length. The seals are usually re-useable a few times.