[T3] Trouble home from Bugorama

[Jim Adney]

On 4 Nov 2015 at 7:03, Jacob Adam Schroeder wrote:

> I had zero compression in cylinder 2 because the exhaust valve broke.  If
> you are interested in seeing the carnage, here it is:

> https://picasaweb.google.com/lh/photo/pXLI0Qm-N97Lyzj7FkY5qNMTjNZETYmyPJy0liipFm0?feat=directlink

It's not broken, it's "burned." It started to leak at some point, and 
the hot exhaust gas slowly eroded away the metal of the valve. That 
said, this is the worst burned exhaust valve I've ever seen. It's 
usually just a small notch. Once you get a notch, there's no longer 
enough compression to get hot exhaust, so the erosion stops. At least 
that's how I always envisioned it.

Here's what I think you should do:

Remove both heads and take them to a shop you trust to do good VW 
work. You can send the heads to RIIMCO if you don't have any local 
options. Ask them to replace any valve guides that are worn past spec 
and replace ALL 4 exhaust valves. Touch up the margins of the intake 
valves and do all 8 seats (3 angle!!! Look at the manual for 
details.) Check all the valve springs for proper tension and replace 
any that don't meet spec. Be careful about replacement valve springs, 
because the last ones I tried to buy didn't even come up to the min. 
spec. Good spring force is necessary to make sure the valve is 
pressed solidly against the seat; this allows the seat to cool the 
valve margin, which is especially important for exhaust valves.

Once this is done, you can put everything back together, or you can 
consider doing one more thing: Remove the #2 P/C and check the bore 
for excess wear. The concern here would be that if #2 was not firing 
for a long time, while gas was still coming in, the cylinder wall and 
the rings might have gotten extremely worn.

Are these the OG 85.5 mm P/Cs? If so, someone may have a used 
replacement that would be better than yours.
 
-- 
*******************************
Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
*******************************