Citroen XM Forum

The bent valve is sticking randomly as the guide must also be slightly deformed as well.
In use the valve rotates slightly each operation, so sometimes the valve stem and guide bends align, sometimes they bind, causing the valve to jam open.

By whichever means you wish, (compression test, leak down test, smoke test, remove head then invert and use liquid in the valve recesses), you need to check all the valves, as ones other than No.4 intake may have been hit. (Xud engines number from the flywheel, not the belt)

You might be lucky and only the two valves on No.4 intake need replacing.

It's worth lapping the whole set whenever the head is removed. Generally, compression loss is due to valve leakage more than piston ring wear.

I'm interested to see how long it takes you, on the floor, complete car back to complete running car.
I've done it on the floor twice with no engine crane, hand tools only and leaving the turbo/manifold still on the car.
If you aren't prepared to butcher parts, I don't think any way is significantly quicker than any other.
The best way is probably to remove the driveshaft, water cooling pipe and turbo oil return, then take the turbo off with the head. You will need the engine crane/helper for that.

Do not judge me by time taken.....I only have 1 hour "work windows" as I care for my 90 year old Mother who has dementia.....so cannot spend a full day etc....COVID prevents Day Care.

I have a good engine hoist and a well sealed garage.

I have a replacement engine arriving in a couple of weeks.

I am fully expecting this to go down the engine out job........

Depending on many factors I still may break the car for parts to recover my costs, this I am undecided on atm and quite reluctant to do considering the rust free condition of the car.

Captured the problem this morning,



I could see F-all with the endoscope I have

Hmm, random valve jamming...the Arthur Daley fix...
Remove cam cover, pry out cam follower, turn the valve so it is fully closed, replace cam cover...
It'll only be one cylinder a bit down on power...

...along with whipping out the oil filter innards to boost oil pressure, and some sawdust in the diff.

Ahhhh.....that is a thought....might as well, I have already put a pair of tights in the diff and some sawdust in the g'box

I actually fell victim to the oil pressure trick back in the early '80s. Bought a Morris 1100 for not-a-lot-of-money as temporary transport, only to get it home a short distance away, and find the oil light was reluctant to stay out when warm. Oil and filter change, to find that the spring had been removed from under the filter element, thus boosting pressure. Replacing the spring left the oil light on permanently. Not good news, and the seller had of course gone AWOL.

Ended up buying a complete Vanden Plas 1300 Auto power unit for £50, off the shelf in Brighton, and quickly fitted that. Car provided reliable transport for two more years, and then got replaced by something much more enjoyable - a Rover P6 3500S.

I'm guessing that you Guys are joking.

Assuming there is only one intake valve bent, the valve rocker trick should actually work giving an engine that has full compression on all cylinders and doesn't keep misfiring due to lost compression.

Multivalve engines were developed to allow more air into the cylinders at high Rpm.
At low Rpm it is desirable to have one valve closed. (Honda V-tec)
I suspect that in normal driving the difference would be undetectable, but really meant that Stickfinger could try this just so he has a fully functioning engine while the car is laid up and he makes a decision on what to do.

The only caveat would be to ensure the cam lobe doesn't contact the valve stem and if possible, remove the hydraulic tappet to stop it jumping out of its holder.

It would be an interesting experiment.

I WILL be doing the rocker/valve cheat.......BUT

Only to move the car outside to clean & de-grease/jet wash the engine bay/undersides prior to putting the car back in the garage.

Good tip

Engine back together minus one rocker/lifter and spring cap.....runs fine, I like 3 1/2 cylinder 2.1td's ...................I am Soooo tempted to leave it at that !

Time to get it out of the garage under its own steam and get the engine bay cleaned/de-greased