Hi NZ_datto,
Yes there is a sequence for tensioning down cylinder heads. There is also a sequence for undoing cylinder heads as well (although this is nearly always over looked by back yard mechanics)
You basically want to do as follows.
1. remove all the necessary stuff so that you are basically standing in front of the car and looking at the cylinder head ready to start cracking the bolts off.
2. Loosen all off the bolts off one at a time (with a breaker bar and preferably a single hex socket) in the following order:
-------rear of motor--------------
4 3
8 7
10 9
6 5
2 1
You see the pattern(basically working from the outside in).
Retension in the reverse order to the one shown above.(working from the inside out)
Note that the bolt marked with a T on the head must be refitted in its original location(9)
When tensioning the head down tighten it down in three stages but always follow the sequence above(working from the inside out)
Stage one : 15 lb ft (foot pounds)
Stage two : 30 lb ft
Final Stage : 40 lb ft
Other points to remember
1. Always make sure before reassembly that cylinder head surface and block surface are very, ver, very clean and free from any nicks or burrs etc.Recommend getting a light head plane.
2. Always check block and head for straightness(with a Straight edge and feeler guages)
3. Always clean out cylinder head thouroughly if it has come back from machine shop(always assume that they havent cleaned it out even if it has been)making sure there is no remains of machining leftovers etc. Where possible blow out all ports with compressed air.
4. Blow out oil from head stud threads in block before reassembly.
5. give threads of head studs a light coat of oil.
Finally I personally recommend using Hylomar Gasket spray on both the engine block and top of head gasket before reassembly. Just for piece of mind its a small price to pay.
Good luck.
Transfer
