2
$\begingroup$

The engine has 12 cylinders and its power is 104000 HP.

Every cylinder has 8 studs M85 which are very slack. I can move them with my hand ( when the nuts are of course not tightened)

Also the gasket between the 1 meter diameter liner and the cover is very soft. I can fold it with my hands

The nuts which are tightened with 2200 bar hydraulic pressure have no washers underneath

If one stud is not tightened not any problem or even two provided that they are not side by side.

Why not any washers, why very soft gasket, why slack studs, why static indeterminancy at the covers

$\endgroup$
5
  • 1
    $\begingroup$ Would temperature rise cause metals to expand? Do all metals expand at the same rate? $\endgroup$
    – Solar Mike
    Jul 19 at 12:50
  • $\begingroup$ Could you provide more information about the engine? Also the sentence "If one stud is not tightened not any problem or even two provided that they are not side by side." is non-sensical, (a bit like "Ap'tin polierxomai kai stin korfikanella") could you rewrite it? $\endgroup$
    – NMech
    Jul 19 at 13:42
  • $\begingroup$ NMech I mean if one or two nuts are missing the cylinder is not leaking from the gasket $\endgroup$ Jul 19 at 20:36
  • $\begingroup$ Are the stud holes also used for lube oil return? These blocks are hard enough to cast without needing another 100 passages for lube oil. Washers provide a consistent surface for improved torque vs tension consistency. If you are using a torque + turn system, you don't need them. The covers will be decently machined where they fay with the nuts. $\endgroup$
    – Phil Sweet
    Jul 20 at 2:38
  • 1
    $\begingroup$ The nuts which are tightened with 2200 bar hydraulic pressure ????? $\endgroup$
    – Phil Sweet
    Jul 20 at 2:39
2
$\begingroup$

The cylinder is cast iron which is relatively soft, so a softer material is used for the head gasket. The soft gasket deforms to seal against the head. Because of the very large size there are more likely machining imperfections that the soft gasket accommodates and seals. Whatever the reason , washers are unusual on engine head bolts. For very large flanges that use a nut on each end of the stud, the stud is not tight because each nut is tight developing clamping force. This cylinder design seem similar.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.