Nach den vorausgehenden Beschreibungen kann es gut sein, daß ein Problem bei der Produktion der Kopfdichtungen bestand.
Aber vielleicht sollte mit auch berücksichtigen, daß die Zylinderkopfschrauben sich tatsächlich, auch wenn man es nicht glauben mag, selbst lösen können, so daß sie nach einer Weile nur noch handfest angezogen sind statt mit dem ursprünglich angewendeten Drehmoment und aus diesem Grund eine Dichtung nicht mehr dichten kann. Die Ursache findet sich beschrieben im nachstehend wiedergegeben Artikel aus den T1-Topics Ausgabe 33. Insbesondere, wenn beim Lösen der Schrauben "großzügig" in der Art der Demontage der Köpfe vorgangen wird, kann das Problem der sich selbst lösenden Kopfschrauben hinterher auftreten. Ein TurboR ist vielleicht noch zu jung für eine Erklärung gemäß dem Artikel, aber ein Cloud wie bei Patrick nicht.
Das ist nicht mein Fachgebiet, deshalb stelle ich den Artikel mal unkommentiert Eurer Lektüre anheim.
Gruß - Udo
CRUMBLING ENGINES
I recently purchased a copy of a paper presented to the British Institute of Mechanical Engineers titles ‘The Design History of a V8 engine. Its author was of course A J Phillips, an engineer fairly well known to enthusiasts. The paper is particularly topical since more and more of these engines are starting to disintegrate. I will reprint the document elsewhere. One of the casualties on the recent Melbourne crusade apparently blew a head gasket in his Shadow. This is generally rare in my experience but then the examining specialist noted that the nuts on the head studs were literally finger tight. These studs are carefully fitted into the very bowels of the engine block and effectively not only hold the head down but hold the whole unit together. It seems that the main casting had lost integrity and the studs had simply pulled themselves out of the block. See arrows below.
I mention this to alert owners to consider any form of prophylaxis that can be taken to halt or at least slow the deterioration of the aluminium castings that are the very body of the engine. Presently I am trying to get the heads off a very early Shadow and so far have had no success. Unlike the old cast iron blocks one would not dare using pullers on these heads for fear of permanent damage so to date the treatment (on advice) has been to rattle the studs with copious quantities of WD40 in the hope that the corrosive grip will let go of the head casting. 479 Corrosion of aluminium engine components is not new to enthusiasts. For over 80 years Rolls-Royce have used aluminium heads on their engines and there are well developed avenues for manufacturing replacement units ex-factory. These are very expensive but reasonable care given the uniqueness of the early cars and the fact that they are holding their value. But a new replacement block for a Shadow is reportedly in excess of $30,000. Add that to the expenses of dismantling, overhaul, reassembly and refitting, the total bill would have to exceed the value of the car by far! At the moment the solution for people such as our Melbourne casualty is to find a used engine that hopefully is recoverable and fit that. Also in Melbourne some very interesting work is being done in fitting an American cast iron vee eight, new. Hydraulics are provided by a belt driven pump and the finished installation is admirable and a fraction of the cost of a genuine replacement. One of these installations was at the Centenary Concours and I had great delight in asking people who should have known, what they thought of the engine. None believe it or not, picked the installation. This of course was a cursory inspection since the tappet covers had not been modified but the finished product runs very well, is just as quiet and best of all the car is still on the road and not being disembowelled in some wreckers yard.
Corrosion of aluminium engine components is not new to enthusiasts. For over 80 years Rolls-Royce have used aluminium heads on their engines and there are well developed avenues for manufacturing replacement units ex-factory. These are very expensive but reasonable care given the uniqueness of the early cars and the fact that they are holding their value. But a new replacement block for a Shadow is reportedly in excess of $30,000. Add that to the expenses of dismantling, overhaul, reassembly and refitting, the total bill would have to exceed the value of the car by far! At the moment the solution for people such as our Melbourne casualty is to find a used engine that hopefully is recoverable and fit that. Also in Melbourne some very interesting work is being done in fitting an American cast iron vee eight, new. Hydraulics are provided by a belt driven pump and the finished installation is admirable and a fraction of the cost of a genuine replacement. One of these installations was at the Centenary Concours and I had great delight in asking people who should have known, what they thought of the engine. None believe it or not, picked the installation. This of course was a cursory inspection since the tappet covers had not been modified but the finished product runs very well, is just as quiet and best of all the car is still on the road and not being disembowelled in some wreckers yard.