Firing on three cylinders

[mojobaby]

Hi Derek, have a look at my thread "Tool for cylinder head bolt removal" from a few weeks ago.
Most importantly, you have to clamp down the liners as soon as the head is off. The head also should be knocked off sideways.
You'll probably have to get a cylinder head gasket before you start, and a torque wrench for when you reassemble.

 

[André4Renaults]

The appropriate sockets can be bought from motor accessory shops:
Notice the really "slim fit" of the outer diameter. This one's a 14mm but other sizes are available. As already said, undo the head bolts & then GENTLY tap the head laterally (side to side) to remove it from the block. Once it's off clamp the cylinder liners in place by putting the head bolts back into the head & using big washers to overlap the liners that can be held in place by the head nuts & bolts. Hope all this helps!

 

[mojobaby]

This is how I clamped the liners down. Without the cylinder head, the bolts are too long, so I cut some metal tubing to the appropriate length

 

[DEREK SLINGSBY]

Thank you all for the advice, now all I need is some time to get out there and investigate more.

 

[DEREK SLINGSBY]

It seems as if cylinders 1 & 2 are doing very little work & that all the graft is being left to 3 & 4! If the valves are only slightly damaged the car would probably run reasonably well at speed and only suffer when under load (cf poor running at about 40 MPH in top.) The emissions will be all over the place, too!

A compression test's a must here!

I know it's a long time but I've just done a compression test, 4 185psi, 3 185, 2 170 and 1 165, do you think I need to take the head off and check the valves or look else where for the cause?

 

[André4Renaults]

I seems my analysis was correct! Cylinders 3 & 4 ARE, indeed doing all the work! When I was a mechanic in a V.W. dealership we were told that when there was a difference of more than 10% in the compression readings then more investigation was called for.... You've a difference of more than that in the case of cylinder no. 4.

First option is to squirt a little fresh engine oil into numbers 3 & 4 cylinders & then do the compression test again on those cylinders. If the readings rise up to the level of cylinders 1 & 2 then it's likely that the piston rings are worn or damaged. But as you have lower readings on 2 cylinders that are next to each other my instincts would suggest the head gasket between cylinders 1 & 2 is damaged, allowing a loss of power between them.

Central France? My wife & I have just returned from Batz-Su-Mer, Le Croissic & St. Nazare after a 3 week holiday. 1,500 miles covered faultlessly in a lovely French car..... no, it was a Citroën Xantia!