XUD9 Valve Stem Replacement

[xsaras4ever]

Hello to all.

Having fried the head in our van - we are now doing a swap.

The head we have acquired was without valves - so we are swapping the valves from our original head.

When getting to do the stem seals we noticed that one of the actual stems is broken.

7 of the 8 poke above the head-casting, allowing a place for you to pop on the new seal.

1 is flush - no possibility of putting on a seal.

How to remove the old stem ???

Do you tap it out from the top to bottom ------ or from the bottom to the top ???

Thanks in Advance

[CitroJim]

You'll need a hydraulic press and a carefully machined mandrel for that... Push out from the bottom I'd advise as the broken edge at the top may scratch the guide bore...

Press the new one in from the top after freezing it overnight to make it as small as possible...

[xantia_v6]

Don't know for that particular engine, but for some alloy heads, you must heat the head to something like 150 degrees to differentially expand the aluminium, otherwise the removal/insertion will permanently damage the head.

[CitroJim]

Don't know for that particular engine, but for some alloy heads, you must heat the head to something like 150 degrees to differentially expand the aluminium, otherwise the removal/insertion will permanently damage the head.

Now that would be an excellent idea Mike Do also still freeze the new guide to make the expansion/shrinkage of both most effective...

Also lubricate the new guide with light machine oil before pressing in and make sure both guide and bore are spotlessly clean and that the press operation starts off perfectly square...

[xsaras4ever]

Thanks for the excellent advice and posts.

Unfortunately - living out here in the sticks in France makes it look like a complete second-hand head at 50euros is an easier and faster option. Damn.

[xsaras4ever]

A quick update.

Broken stem is now out.

Good stem is also removed from fried head and is resting in freezer.

Done at home with a collection of homemade tools and some head-scratching.

Hoping to fit replacement guide in the morning and continue with the job.

We had fried the head because the van dumped all of its water late one night and gave no warning lights. We only discovered it had happenned when we pulled up outside our house and shut the engine down. We were enveloped in a cloud of steam.

The following morning we spotted a trail of anti-freeze - leaving our village and continuous for about 2km.
Strangely the van never even emmited a smell.

No compression when we tried to start it.

A bottom radiator hose had been chaffing and a previous owner cable-tied some polystyrene pipe cladding around rather that tying the hose out of harms way.

Of course it chafed through the cladding and continued to wear away at the hose.

[CitroJim]

A quick update.

Broken stem is now out.

Good stem is also removed from fried head and is resting in freezer.

Done at home with a collection of homemade tools and some head-scratching.

Excellent! Good work sir

How hard was it to remove the broken stem?

[xsaras4ever]

Got a seat bolt from a Xsara.
Its thread is correct to go inside the stem and it has a round head with the indent for a torx.

Run the head of the bolt on the grinder to reduce it just smaller than the bore in the head for the stem.

Put the bolt into the stem.

Find a socket the same size as the cam bucket and pop it into the head (put the socket upside-down)
Now put another tight-fitting socket (right way up) into the larger socket.

You now have a sort of guide nicely fitting inside the head.

Put a long torx into the 2 sockets.

We have a homemade press. Basically a square frame with a plate at the bottom and a plate at the top.

We put the head on it, put a bottle-jack onto the torx (with a spacer to spread the load).

Hey presto - we pressed out the stem.

Hope this explanation makes sense.

[CitroJim]

Yes, what an excellent explanation and way to do it! That is utterly brilliant! I offer you my heartiest congratulations on a job very well done

Xsara seat bolts are going to be in great demand from XUD9 engine reconditioners now

[xsaras4ever]

Thanks Jim.

Bet its all downhill from here though - and not in a good way - knowing our recent luck with cars

[xsaras4ever]

Couldn't wait.

Replacement stem is now fitted.

The stem is slightly domed on the piston end which allows it to be started.

It has a step on the top of it - this allows the oil seal to sit down properly.

We placed an 11mm (1/4inch drive) socket onto this step. Then we fitted a short 1/4inch extension and gave a few gentle taps to start the stem into place.

We got a high tensile threaded bar and put 2 nuts on one end. Then we fitted an electrical heat-shrink on the bar (to an equal length of the stem)

Remove the entension but leave the socket in place.
Pop the threaded bar down from the top into the socket.

Steel strap with a hole in it on the threaded bar at the piston end to block it against the head.

Next fit 2 well greased washers and a nut.

Tighten the nut and it pulls the stem into place.

The heat-shrink stops the bar from scoring the stem.

Note: we only touched the stem while wearing vinyl gloves to not warm it too much after its holiday in the freezer.

Both of the methods are probably "how not to do it"

[xsaras4ever]

Well as usual - our luck comes to bite us in the rear.

Ground the valves in and fitted new stem seals and then fitted the valves.

Fitted the cam buckets.

Fitted the camshaft.

Camshaft tight as hell - wouldn't turn.

Off with camshaft - out with the valves.

Fitted the camshaft to the bare head - tight.

Dug out the original broken camshaft (3 pieces) that was on this replacement head. It was at the bottom of our scrap-pile.

The centres of both camsfahts are the same dimensions but for the bearings at either end, the camshafts are different.

The difference is 0.2 mm

Thats on the diameter - so it is 0.1mm on the radius.

We have the correct bearing caps so we could possibly lightly sand the head to find that 0.1mm

We know that all of this is accurately machined but a gently rub with fine paper wouldn't hurt too much.

[CitroJim]

Ahh yes, the cam journals and caps are line bored as a set and the caps cannot be swapped around... Cams can usually be swapped if the caps are known to be a perfect set that go with the head...

One work-around is to 'scrape' the journals, as is done with white-metal bearings in the old traditional way, until you have the correct clearances as measured with a bit of plastigauge...

The cam journals should be far too hard to make any impression upon except by precision grinding...

You may find it is only one journal causing a problem...

[electronmirror]

When I started to read this thread I couldn't for the life of me visualise what was being referred to as 'the valve stem'

The penny dropped with the realisation that what was actually meant was 'the valve guide' in the head, the stem is an integral part of the valve.

The only reason I mention this is because many of the forum members outside UK don't have English as their first language and they might be scratching heads in puzzlement

Well done on the job so far, my brother lives in a rural part of France and similarly has to improvise on many things automotive. Good luck with fettling the camshaft journals and caps.

[xsaras4ever]

Thanks for the posting Electronmirror- you are right of course about the terminology - sorry.

Things have moved on a bit with the van - firstly in a good way then in a disasterous way.

We put 600 grit sandpaper around a suitable sized long socket on an entension bar and sanded the journals in a horizontal way , checking the cam after each 300 strokes of sanding.

After 1500 sandings of each journal (4500 in total) we had a nicely fitting cam.

Fitted the head back on - new timing belt etc.

Started it up, quite easily.

It worried us because it burbled through the expansion bottle a bit but we prayed it was just airlocked in the coolant system - no bleed valve in this set-up.

Torqued the head down when warm - all good and the coolant system settled down.

Started it up 2 days later - great. 20 seconds later it dumped oil in a puddle on the ground.

Nipped the rocker cover bolts up a bit - we had fitted a new rocker-cover gasket.

2 days later - same thing - but by the time we noticed, the oil had stopped so we let it run for 30 minutes - no problems. Took it out for a half hour drive - great.

Took the rocker cover off and sealed it with joint compound. let it set for a day.

Started it this morning - no leak.

Looked under it - nothing.

Noticed the engine note changing - then it went mad.

Maximum revs - we shut the key off - nothing. Threw the key into the garden in frustration-fear.

Forced it into reverse and tried to pop the clutch and stall it - no luck.

Van revving at maximum - clouds of smoke everywhere - village obliterated in smoke - neighbours out of their houses chattering..................

Put our hand under the bonnet and pinched a diesel pipe to stop the flow. Engine eventually stopped.

Cripes - if we had been driving it ----------------it doesn't bear thinking about.

We think that on startup that pressure was building up and forcing the oil up and out. When we sealed it, that oil got into the cylinders and ignited with the diesel - hence the engine was over-fuelled and hence the revving and mega smoke.

Aint touching it - only to rip that engine out and send it to the scrap.

Will fit a good old ZX 1.9d engine with suitable flywheel and sump modifications.

It was just too good to be true...............