NG headwork - carbon deposits

[Swann, Benjamin R. (BSWANN)]

Thanks Javad,

Since the valves are out now and I'm already 1 step from putting in new
seals, I'd prefer not to take this to a machine shop.  How would they remove
the carbon from the valves.  Is there some kind of solvent.  I don't mind
using an abrasive, just I don't want to do more harm than good.

I wish I had a metal lathe, but perhaps I can put these in the drill press
and carefully clean them by spinning.  I was just going to hand lap the
valves in place.

Basically, I'm trying to do this all myself.  If I wanted to I'd just go buy
a performance motor, or even a new car.

This project started over a year ago and I will just keep moing ahead at the
snails pace 'til I'm finished.  Well right now I'm trying to be a fast
snail.

	Thanks again.

Ben
'85 4000csquattro - project GTQ moving forward again.


-----Original Message-----
From: JShadzi at aol.com [mailto:JShadzi at aol.com]
Sent: Friday, July 06, 2001 10:47 AM
To: BSWANN at arinc.com; quattro at audifans.com
Subject: Re: NG headwork - carbon deposits


Ben, you are right, the valves don't really need to be unshrouded.  As far
as 
the carbon deposits, it wouldn't be a bad idea to take your head to a shop, 
for about $150 they can clean up all the valves, lap the seats, and put in 
new valve guides and seals.  This would be a really good idea, especially if

the head has over 100k miles.  Personally, I would want those deposits off 
the valves.

As far a porting, one of the best tricks I know of, esp. on the NA cars (the

turbo cars need all the valve seat surface they can get) is to have 1.5mm 
machined out of the ID of the valve seat, which can effectively be like 
putting in 1.5mm bigger valves.  I always go inside the bowl areas and
smooth 
them out, and the nub that supports the valve guide can be brought down on 
the sides to make it more elongated when looking from the top.  The "short 
side radius" (where the valve port turns 90 degrees or so) can always use 
work in smoothing, often there are sharp edges here from machining of the 
head originally.  

The exh. port turns exactly 90 degrees to go to the manifold, I always spend

a lot of time on the SSR here and often it can be a sharp 90 degree bend 
here!  Then, overall smoothing of the ports, I like to finish everything off

with 200 grit, you don't want any of the area AFTER the injector to be shiny

smooth, a little tumble will help atomize the fuel.  Port matching the IM to

the head is probably the biggest gain to be had, and of course, the IM can 
always be polished and opened up more, at least get the 1/8" of grease that
I 
always find in there!

HTH, let me know if you have Q's about specific areas.

Javad
www.80tq.com


In a message dated 7/6/2001 6:29:04 AM Pacific Daylight Time, 
BSWANN at arinc.com writes:

<< Any tips on porting or polishing for this specific head would be
 appreciated.  I understand from previous posts, that the valve  seats don't
 need to be unshrouded.  I'm not looking to remove much material, only to
 clean up some casting imperfections, mostly on the manifold side.
  >>