Rebuilding Head

[sleepydsm]

Cylinder head is off of a 1992 6bolt Tsi AWD 5spd with 142k. I have a feeling my head is warped, so I found a place to machine the head. I talked with the guy, and I'm planning on: getting the head decked, a valve job, new guides for the exhaust side, cleaning the head, and fixing a broken stud. Is there anything else I should replace or do while it's all torn apart? Intake valve guides? Valve stem seals? Etc. Thanks!

[MustGoFaster]

Valve stem seals?
Yes, always replace them, plus they typically get removed and destroyed for/during machine work.

[Jakey]

Are you going to be using OEM valve guides or manganese-bronze guides?

[sleepydsm]

Are you going to be using OEM valve guides or manganese-bronze guides?
I don't know honestly. What is cheaper, and what is better and why?

[Onefast99gsx]

The bronze will disipate heat better I understand.

[JET]

Honestly I probably wouldn't even mess with the guides unless you think there is a reason for them to be bad (TB went or something). I would have the seats reground, decked, and tanked. Always use new valve guide seals. If the valves are nasty you can have them lapped and cleaned up too.

[Jakey]

Always use new valve guide seals.

You mean valve stem seals such as these: http://www.engintecs.com/viton.jpg? :D

[JET]

Yep, typo. I was talking about guides earlier in the post and accidentally typed guides again. They do go on the valve guides though :D

[sleepydsm]

Well actually the guy is checking all the guides, and replacing the bad ones with iron ones. I talked with him about the differences of Iron vs Bronze, and he said the Bronze does not hold up well with high heat applications, such as a turbo motor. He said the iron would be a better, cheaper, and easier to install option. And yes I'm getting new stem seals, and a bunch of other stuff.

[rick shindley]

Typically the exhaust valve guides will have to be replaced. They wear out well before the intake guides do.

You mentioned that you thought he head was warped. If it is, throw it away! Youc anget the bottom of it made flat but what about those cam journals? They will be out of alignment if the head is warped! (You would have to have the cam caps cut and the the head line honed to correct for the warpage. Too many $ spent.)

If you want more performance form that head consider mildly porting it with the valves out. Eliminate the sharp edges around the valve seats. Clean up the "valve bowl" region and make the intake port floors flat. Don't go nuts with it. Doing these few things really helps the motor breath. It makes a noticeable difference in performance!

If you wan tot test a head for warpage, remove the lifters and reinstall the cams. turn each cam with your hand. If they trun easily, the head can be planed and it will be good to go. If they bind, the head is junk.

BTW, planing a head (and block) will make the cams slightly out of time. You should have adjustable cam gears and have the cams "dialed in" if you want the last ounce-inch of torque from that motor!

Rick