Rebuild or Replace Cylinder Head Options

[6G96GT]

So my head is getting to that point where something is needing to be done. I am thinking about rebuilding it and then porting and polishing the combustion chamber and possibly milling the head for some light compression gains. Here's the question...What's more expensive, having the head rebuilt at a shop or buying a rebuilt head on ebay or somewhere else and then having a shop simply switch the heads? Thanks

[hurley97]

The majority of the work involved in getting the head off is disconnecting everything around it.

Some tips if you decide to do it yourself:

- Before taking the cams out put a bolt in the threaded hole. I believe it's the intake cam (I know it is on the 7A, I can't remember if the 5S was the same) There's a spring loaded scissor gear that is a pain to get back where it should be if it unloads. One of the bolts from the timing cover should fit perfectly.
Notice the gears on the bottom cam that aren't lined up...


- The correct way to take the cam caps off is to take off the one on the end first, then go to the opposite end and work your way to the middle. The order for taking them off doesn't matter as much as putting them back on.

- If you take out the shims and buckets to do the valve seals, make sure to label the shims and keep them with their own buckets. They need to go back in the same place they were in otherwise your valve clearances will be all wrong.


- When unbolting the head start on the ends and opposite corners and work your way in. When re-bolting it back in do the opposite. First torque them to 36 ft/lbs, make a mark on all the bolts so you know the current orientation, then turn them all another 90 degrees again in order.
Removing:
3 5 10 8 2
1 7 9 6 4

Installing:
8 6 1 3 9
10 4 2 5 7

- Oil all the threaded ends on the bolts, they torque more true to spec when you do.

- Make sure you line the cams up properly or the car won't start, or start and run really bad depending on how far off they are.


That's all I can think of right now.