Re: [T3] No. 2 Exhaust Valve Problem

[Jim Adney <jadney@vwtype3.org>]

On 31 Aug 2002, at 16:07, John Jaranson wrote:

> OK, I am looking for some advice from the experts out there.  As I mentioned
> the other day, the exhaust valve on Number 2 cylinder was tightening up.  I
> pulled the head today and the #2 exhaust valve is clearly more recessed in
> its seat than #1.  It is not real obvious in the pictured

Are you sure that something has changed? It is quite common for seats to 
get ground to slightly different depths. I would take the valves out and find out 
exactly what has changed; that way you could see whether a valve has 
stretched or a seat is sinking. 

It is clear that the #2 head has been running colder. Any idea why?

> What are my options?  Can I get a new seat and install it?  Should I just
> get a new head?  How long can I run on this head the way it is?  (The valve
> tightened up in 800 miles or so)  What can I expect as a failure mode, if I
> don't do anything right now?  Am I likely to do damage to parts beyond the
> head when it fails?

A new seat tends to get pretty expensive. I may have a good used VW head. 
If the head of the valve breaks off it can ruin the whole engine....

> I also included a shot of the #2 Piston top.

I can't really see anything here.

> It also looks like I may have been getting a little blow-by between the
> cylinder and the head.

I don't care for the high/low pattern that you see in the ends of both cylinders 
as well as in the sealing surface of the head. I lap the cylinders on a flat 
surface to make sure they're flat, and I flycut the heads just enough to clean 
up and flatten the sealing surface. I'd like to know which of your parts has 
that odd wavy warp to it.

-
*******************************
Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
*******************************

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