Rebuilding Head

sleepydsm · 08-08-2005

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 · 08-08-2005

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

Jakey · 08-08-2005

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

sleepydsm · 08-09-2005

Quote:

Originally Posted by Jakey

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 · 08-09-2005

The bronze will disipate heat better I understand.

**JET** · 08-09-2005

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 · 08-09-2005

Quote:

Originally Posted by JET

Always use new valve guide seals.

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

**JET** · 08-09-2005

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

sleepydsm · 08-09-2005

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.

08-18-2005

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

**JET** · 08-18-2005

Quote:

Originally Posted by rick shindley

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!

Rick

I strongly disagree with the last 2. Don't reduce the floors on the intake side. The intake side on a 1g head flows so freely that all you have to do is clean up the casting flaws and do a little port matching. The bowls are also very good from the factory. Most people mess those up when they are trying to do good. The big place to gain HP is on the exhaust side of the head. The runners can be opened up a lot and the dividers thinned down.