Head Gasket Replacement
Home | About Me | My Minis | News | Technical | Photo Gallery
Home > Top Level > Technical > Engine > Head Gasket Replacement
Head Gasket Replacement
Pages: 1
Having had one head gasket blow between the #2 and #3 bores was bad enough, then it's replacement decided it wanted to leave the block by sneaking out from the side of #4. Somehow during it's escape attempt, it also managed to short out something and blow a fuse!
Changing a head gasket is fairly invloved, but doesn't take too long, and after changing a few it can be done in less than 2 hours, as long as there are no complications.
The standard exhaust has a distinct advantage in this case, allowing you to just undo the clamp that secures it to the manifold and swing the complete manifold clear. If the car is fitted with a non standard exhaust, such as a Maniflow, these this needs to be removed so that the manifold can be manouvered out of the way of the head. As is the same for the inlet manifold.
Other bits that need to be remove are; heater hoses, top radiator hose, ultimate engine steady, top radiator bracket, bypass hose and rocker cover. You also need to drain the water in the engine so it's lower than the top of the block. With all of this junk out of the way we can now get down to work. You may want to loosen the rocker adjusters, this is sometime necessary to avoid bending the push rods when every thing goes back on.
You can now start loosening the head nuts one by one starting from the outside in, one flat at a time until they're all loose, then remove them completely. You may find that some of the studs come out with the nuts, just take them out and remove the nuts later.
With all the head nuts removed you should now be able to lift the head free.
And here's what I'm confronted with. Looks like there may not have been enough pressure on that part of the gasket, allowing the combustion gases to push it out of the block. Note that you can also see the drilling for the 10th stud in this photo, but the head i'm using is drilled for 11 studs, I don't think that this was a contributing factor as the head gasket has a hole here anyway.
Now it's just a case of cleaning away the remnents of the old gasket, cleaning the block and head mating surfaces of any gunk and if your brave de-coking the piston crowns with a blunt object. Assembly is the reverse of disasaembly remembering to torque the head down correctly and after running the engine gently, allow it to cool and re-torque the head nuts.