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|Hall of Shame||Gasket changed||Stretch bolt 2|
The K Series head gasket failure and stretch bolts at the MGF / TF
An update on the bolts!
The bolts will leave
a healthy margin on cylinders 1/2 as the deep part of the sump is below
the danger areas.
The bolts are approx 412 long with 72mm thread,the block is 282mm height and the oil rail is 25mm thick. The critical bolt is the front one between 3/4 cylinders because if the bolt is fitted to the block the measurement before it hits the sump is around the 99mm mark, from block to u/s of bolt head.
So if you have a head skimmed and it is say 99.5mm when bolted in position there is a strong danger of this bolt bottoming on the sump and not stretching as it was designed. There is approx 72mm thread on the bolts into a 25mm plate so removing the 4/5mm will not affect the depth of thread in the plate as the bolts protrude 8-9mm below the plate into the sump area. I doubt there is a danger of the bolt running out of thread as the block and head measure approx 382 and the unthreaded section measures about 340 this would mean the bolt would have to stretch some 42mm!!!
The ideal solution
is to have bolts that measure 405mm long IMO. I hope this is clear enough
but to summarise the bolt between cyl 3/4 on the front of the engine needs
to have a safe margin of say 97mm protruding above the block face when
screwed in finger tight.IMO.
Type: TORX MALE (F)
10 OFF M9x1.25x412
of shame MGFs Cylinder Head Gasket Failure
mg enthusiasts hgf_june_- september.htm written 1999 to the MG Enthusiasts BBS
changed !! (08/2001)
More stuff written
to the MG
Land Rover introduced a new design Head Gasket and Oil Rail to improve the engine and decrease head gasket failures.