Reply To: Exhausted!

[BernieParticipant]

I offer two contributions to your dilemma:

1) My observations – I do not believe a leaking liner seal can possibly allow coolant to get into the combustion chamber.

The seal is between the liner and the block so any coolant getting past it will go directly into the crankcase/sump.  Even if a large leak leads to a sump full of coolant/steam I cannot envisage how it might possibly by-pass the piston (from below) to get into the bore.  On top of that, there is apparently no coolant in the oil so, again, I think the liner seals must be intact.

My next thoughts are therefore that the problem is either a cracked head or blown gasket.  In my mind a third possible solution would be a split in the liner wall, between the water jacket and the swept section of the bore, but I have never ever heard of that happening.

2) If you do need to remove and refit liners – At the time the manual was written, the standard engine was the “Perfo” and the liner gaskets were a relatively thick, spectacle shaped, wire-reinforced composite construction, each of which sealed two liners.  Their thickness meant the barrels had to be significantly shorter than the height from the seats in the block to the head surface of the block.  The design changed with the introduction of the D engine when liners were taller and the thick gaskets were replaced by a much thinner shim-like paper or polymer item.  The latter are normally single cylinder gaskets but I have also seen them cut in pairs.  As long as they are correctly fitted without rupturing or overlapping, they create a very good seal.

If you still have original Perfo liners and intend to refit them you will need to obtain the correct style gaskets and follow the procedure in the manual whereas a new set of liners will normally be supplied complete with gaskets.  In the latter case, new piston/liner sets plus the gaskets will be those for a standard (un-modified) D type block.  If you obtain an “old new-stock” piston/liner set you should first determine whether they are Perfo or D.

Phil Allison and I have recently rebuilt a pair of 6-cylinder engines – the liner assembly is the same as that of the fours. The method we used was as follows:

Having cleaned the liner seats in the block the liners were fitted without any gaskets in place and the whole of the head surface of the block/liner assembly was machined flat.

The engines were then assembled with new liner gaskets of the correct thickness to give the specified stand-off.  The book states the liners should stand 0.05/0.10mm proud of the block surface so we used 0.08mm thick gaskets (obtained from Darren Brownhill of Citroen Classics) and my rebuilt 6 engine has now done about 3000 miles without (gasket) problems.  Over the years I have assembled a number of engines in this way and have never experienced any failure of either the liner gaskets or the head gasket seal at the top.

N.B. – A key factor during assembly is to align the flats on the OD of the gaskets so there is no overlapping and then ensure the liners are firmly secured until the head is fitted so they cannot be disturbed possibly damaging the gaskets.

B……………………