[T3] Heads are toast, rebuild time

[Jim Adney]

On 29 Jan 2014 at 21:56, Jacob Adam Schroeder wrote:

> Jim had suggested that running too rich may be causing my clearance
> issues.  That would be fantastic (if I can remedy the clearance issue
> without doing a rebuild or pulling the heads).  My heads have BR and VW
> stamped in them, so I imagine they are VW Brazilian heads and I'm hoping
> they would not give out after < 10k miles.

My thinking was backwards when I made that suggestion. Rich running 
resulting in carbon buildup on the valve seats would make the 
clearances increase, not decrease. Sorry.

I still don't understand what might cause this, but maybe the BR 
heads are just defective. This seems odd, since I get the impression 
that you've had this engine for some time and this problem just 
started. Perhaps the person you loaned the car to did something to 
cause this (or am I confusing your situation with someone else's.)

I believe you said that you don't have the thermostat installed. In 
that case, especially in cold weather, your engine would never really 
get fully warmed up and the FI would always be in startup (rich) 
mode. That would explain the poor gas mileage. Normally, I would 
expect gas mileage in the 22-24 mi/gal region, so I don't think 
you're far off.

Running without the thermostat and flaps is always a bad idea, 
especially in cold weather. It's especially bad with the FI, which 
responds to engine temp. Carbs are different: If they have chokes 
they warm up independently of the engine, or they simply don't have 
chokes.

Perhaps there's something about rich running that would make the 
valve seats wear quickly. I've not heard of this, so I'm skeptical 
about the possibility. One thing you should probably check would be 
your charging system. With the engine running at medium rpm after a 
warmup drive, the battery voltage should be 14.1 - 14.4 V. If it's 
below 13.5 V you should replace the voltage regulator with a Bosch 
30-019. Low system voltage will make the system run rich.

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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